POLISHING CONCRETE

A Durability + DesignCollection

Polishing ConcreteA Durability + Design Collection

Copyright 2013 byTechnology Publishing Company2100 Wharton Street, Suite 310

Pittsburgh, PA 15203

All Rights Reserved

This eBook may not be copied or redistributed without the written permission of the publisher.

Introduction

Contents

ii

1iv.

79

162329

A Real Grind: Concrete Polishing “101” Offers Multiple Rewardsby Gary Henry, Durability + Design

Concrete Flooring: Polished or Coated?by Gina R. Johnson, Durability + Design

Crunching the Numbers on Polished Concrete, Other Flooring Typesby Walter Scarborough, HALL Building Information Group, LLC

Artistry and Chemistry: Color Theory and Practice with Polished Concreteby Howard Jancy, Jancy & Associates

Keeping the Shine:Basic Training in Maintenance of Polished Concrete Floorsby Howard Jancy, Jancy & Associates

34 Defining the Undefinableby Brad Burns, Concrete Polishing Association of America

Getting Up to Speed on Concrete Polishingby Mark Vogel, W.R. Meadows

SPONSORED BY:

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iv

IntroductionThis eBook consists of articles from Durability + Design(D+D), durabilityanddesign.com, the Journal of ArchitecturalCoatings (JAC), and Painting and Wallcovering Contractor(PWC) on the subject of polished concrete coatings. More articles on this topic may be found online at durabilityanddesign.com.

Cover image courtesy of BradBurns, CPAA. See the full

article on page 33.(Right) Photo courtesy ofH&C Decorative Concrete

Products

1

Getting Up To Speed onConcrete Polishing

Editor’s Note: This article appeared inJAC in December 2008.

By Mark Vogel,W.R. Meadows

Enhanced performanceand appearance attributes have contributed to the increased use of polished concrete in avariety of public andinstitutional settings.This article reviews theconcrete polishingprocess, includinggrinding, surfacepreparation, densifier application and polishing.

T he range of flooring options available intoday’s marketplace is vast, with each of these alternatives offering unique appearance and

performance characteristics. As a result, owners and design professionals must evaluate many factors to determine the best flooring option for a structure’s givenneeds and environment.

Grinding, densification systems get sustainability points for buffed-upfloor performance and appearance attributes

2

One flooring system or option currently gain-ing in popularity is polished concrete. Al-though polished concrete is relatively new inNorth America (approximately 15 years), thesystem offers many advantages.Concrete is a durable material, and thus

meets an important sustainable-design crite-rion. In addition, the polishing process en-hances concrete’s natural appeal. Theseattributes have contributed to the increased useof polished concrete in public and institutionalbuildings such as schools, hospitals, retailstores, restaurants and other settings. In this discussion, we will seek to provide a

review of the polished-concrete process, whichinvolves a sequence of steps that begins withinitial grinding and preparation of the floor.Application of densifying agents and polishingwith machines employing diamond-grit discsproduce a surface that is durable, attractive,and highly reflective. A major factor in the in-tegrity and performance of polished concrete isthe use of high-quality liquid hardener anddensifier materials.

Polished concrete: An overviewPolished concrete, because it does not involvea coating, is a breathable system—one that al-

lows transmission of water vapor and thus isnot subject to failure due to moisture migrationfrom below. When properly installed and maintained,

polished concrete can last the life of the struc-ture, avoiding the time and labor of installingsubsequent flooring systems.Polished concrete can be used in almost any

interior area. In exterior settings, however, acidrain has a tendency to prematurely etch the sur-face and cause early deterioration of the shine.Polished concrete can be treated with integralconcrete colors, color dyes, and edge-tintingproducts to produce an attractive floor surface. Maintenance is relatively simple and eco-

nomical, and involves cleaning the surface withan agent formulated for this purpose. A con-centrated cleaning solution with a neutral pH isadded to the cleaning water in an auto scrub-ber. The auto scrubber applies the cleaning so-lution, buffs, and vacuums any remainingsolution and dirt particles, leaving no residueand a clean surface. Maintenance of polishedconcrete is quite low in cost, averaging 5 to 7cents per square foot per year. No specialwaxes or strippers are required.

Dry or wet processWith dry polished concrete, vacuums are usedto extract dust; with wet polished concrete,wet slurry is used to remove concrete parti-cles. The wet-grinding process requires spe-cial disposal methods. With dry polished concrete, pre-separators

and vacuum systems are used to control air-borne dust and contaminants. The dry powderor cement particles can be safely disposed ofand can even be recycled. Incorporating alow- or zero-VOC (volatile organic compound)hardener/ densifier completes a “green,” en-vironmentally friendly flooring system. A densifier works by chemically converting

weak calcium hydroxide [Ca(OH)2] and cal-cium carbonate (CaCo3) compounds in the

Polished concrete can be usedin almost any interior area, andcan be treated with integralconcrete colors, color dyes, andedge-tinting products to produce an attractive floor surface. Photos courtesy ofW.R. Meadows Inc.

3

Attaining the desired level ofshine in polished-concrete

installations depends on thenumber of passes of the

diamond disc grinder, as eachstep increasingly flattens the

floor and enhances light reflectivity.

concrete to form calcium silicate hydrate(CSH). CSH is insoluble in water and is highlyresistant to water, acids, and other chemicals.The formation of the CSH is proportionate toincreased concrete hardness and density dueto the replacement of soluble lime [CA(OH)2]with CSH. Once the concrete pores are filledwith CSH, migration of moisture from the sur-face to the substrate will be inhibited, as theprocess produces a hard, dense, and sealedsurface in which abrasion resistance is in-creased by approximately 50%.Concrete densifiers are typically based on

lithium silicate, sodium silicate, and potassiumsilicate.

The process stepsA true grinding and polishing system requiresa process consisting of five to 10 steps, de-pending on the desired shine of the floor andits original condition. Assessing the conditionof the concrete requires on-site analysis, gen-eral knowledge of concrete and mix design,and diagnosis of hardness, porosity, and ag-gregate types. Grinding and polishing techniques are di-

vided into two categories: Those employingmetal-bonded diamonds (16 to 150 grit) thatare used in the initial grinding or preparationphase, and resin-bonded diamond segments(100 to 3000 grit) that are used in the subse-quent polishing phases. Metal-bonded dia-monds are more aggressive in their effect onthe concrete substrate than resin-bonded dia-mond segments. The initial grinding step removes high spots,

imperfections, and contaminants such as cureand seal materials, mastics, or chemicals. Thisgrinding phase may require one to threestages, but it will consume 60-65% of the totaltime required to complete thedensification/polishing process. Grinding andprep work are critical, however, in achievingthe ultimate result in the final floor finish. Resin-bonded diamonds are used following

application of the hardener/densifier to polishand remove the scratch pattern created by theinitial grinding process. The three primary degrees of shine are cat-

egorized based on the diamond grit of thefinal polishing step: 800, 1500, or 3000—which translate to semigloss, gloss, and high-

4

gloss finishes. The cost increases incrementallyby 10–15% when upgrading from a semiglossto a gloss range, and another 8–12% whenupgrading from a gloss to high-gloss range,based on the total value of the project. The ma-jority of the cost is related to the preliminarypreparation stages, as labor intensity is great-est in the grinding stages.A mock-up at the job site is always the best

way to identify the capabilities of the desig-nated slab and its affinity to the polishingprocess. In addition, the mock-up can help de-termine the polishing level needed to suit thebuilding and achieve satisfaction of the cus-tomer and its occupants. A final, optional step involves application of

a type of topical or penetrating agent to im-mediately seal the surface until the densifiercan fully develop to its potential. Because thedensifier must fill all the voids in the concretethrough a chemical reaction, sealing does nothappen immediately and is highly dependenton the porosity of the concrete.

Densifying and hardeningOnce the metal-bonded diamond phase andprep is complete, the densification process be-gins. This key step plays a central part inachieving longevity of the shine and a highlevel of performance of the finished floor. Den-sification results in a water-, stain-, and chem-ical-resistant surface.After the initial grinding stage “opens” the

concrete to facilitate the chemical reaction ofthe densifier and concrete, a sprayer orsqueegee is used to apply the liquid densifierat a rate of 16 to 19 square meters per liter(175 to 200 square feet per gallon). The den-sifier is allowed to soak in for 10 minutes, andis then scrubbed into the surface for 15 to 20minutes (or until gel formation) with a broomor, preferably, an auto scrubber for optimumpenetration. This is followed by a light mistingof water, and then a re-scrubbing and flushing

of the remaining material from the surface, de-pending on heat and airflow conditions. Spe-cific manufacturer directions should bereferenced, as some application methods vary.It is critical to not allow the densifier to dry

on the surface, as this may leave a whiteresidue or haze. Large quantities or concen-trations of densifier left on the surface are dif-ficult to remove and may actually stain theconcrete a dark color. Water is used to help re-move any remaining densifier.The recommended temperature and humid-

ity ranges for densifier application vary frommanufacturer to manufacturer; product guide-lines should be referenced. The installer canextend the application time by adding moredensifier in the first 15 to 20 minutes, as theconcrete can readily absorb the additional ma-terial. Water can be added after 20 minutes,as this will thin the densifier material as it gelsto help facilitate deeper penetration and sim-plify the job of removing excess product. The environmental profile of the densifier

product also plays a primary role in the“green” credentials of the specific concrete-polishing process. This profile is determined byVOC content, the nature of the waste materialgenerated, and disposal parameters. The entire densification process takes ap-

proximately 30 to 45 minutes. The surface isthen allowed to dry for 24 hours before theresin-bond diamond segments are used to pol-ish to the desired level. The process produces ahard, dense, and sealed surface.

Adding colorIf coloring of the concrete is part of the pic-ture, numerous options are available, includ-ing integral coloring of the concrete, staining,and dyeing.With integral coloring, an admixture is in-

corporated in the concrete mix to produce uni-form color throughout the slab. With a dye orstain, the concrete surface is colored before

5

applying the densifier, allowing unlimited colorcombinations and edge-tint options. Dyes orstains are typically applied after polishing atthe 400-grit level. A second coat may beadded later in the process or at the end to in-crease the effect or intensity of the color. Careshould be taken to wash the surface of dyedor stained sections with water, followed bycomplete drying before the next polishingphase begins.

Levels of shineAttaining the desired level of shine depends onthe number of passes of the diamond discgrinder, as each step increasingly flattens thefloor and enhances light reflectivity. Polishingsystems that require minimal process steps—less than five—do not constitute a true grindingand polishing system, which involves a five- toten-step process, including the hardening anddensification application. These less-complete (and lower-cost) types of

systems are commonly referred to as topical, astheir penetration of the surface is limited, leadingto early wear and loss of gloss and reflectivity.

The safety issue: Polishing and slipContrary to a common perception, the degreeof polish or shine is not directly related to slipresistance. A 400-grit finish can and usually isless slip-resistant than a 1500- or 3000-gritfinal finish. It helps to think of it in this way: when a floor

is wet and a person walks on it, the peaks andvalleys in the landscape of the surface create atendency for the person to “hydroplane.” On acompletely flat surface such as that producedby 1500 or 3000 grit, the water is pressed outfrom under the shoe, putting the sole directly incontact with the concrete surface—actuallymaking the shoe stick to the surface. A true grinding and polishing system with

the highest levels of shine (using 3000-gritpolishing) and gloss (gloss meter readings in

the range of 45 to 65) exceeds OSHA (Oc-cupational Safety and Health Administration)and Americans with Disabilities Act (ADA)standards for coefficient of friction and slipresistance, which are the two most widely ac-cepted standards for these safety criteria. Theprocess creates an attractive environmentwith increased light reflectivity, a desirablecharacteristic in today’s safety-consciousmarketplace.Standard coefficient of friction (COF) num-

bers for an 800-grit or semigloss polished-con-crete surface will range from .79 to .84, a1500-grit or gloss finish will yield a COF of.84 to .87, and a 3000-grit or high-gloss fin-ish will yield a COF of .87 to .89. These num-bers all exceed the OSHA standard of .50 andthe ADA standard of .60 on flat surfaces. Theflatter the floor, the higher the standard of co-efficient of friction.

Polished concrete: An effective solution on several countsWith the vast amount of flooring options avail-able today, architects, specifiers, and ownersare well advised to consider all available op-tions to meet the needs of a structure and itsoccupants. Issues such as durability, safety, ini-tial and ongoing maintenance costs, replace-ment needs, the service environment, and theenvironmental profile of the system should beweighed in determining the ideal flooring sys-tem for the given setting. Polished concrete canprovide an answer to many of these needs byenhancing a common building component—concrete—that meets the definition of a sus-tainable building material in many ways.In evaluating any flooring option, it is impor-

tant that best practices and detailed specifica-tions are employed. Effective choices regardingflooring systems can deliver safe, environmen-tally friendly solutions that are cost effective andcontribute to the highly coveted goal of sus-tainability in design and construction. D+D

6

They may be making a extended pit stop

for cosmetic alterations, but the sleek

racing cars at JKS Motorsports in the

heart of North Carolina’s NASCAR coun-

try almost appear to float on the shim-

mering polished-concrete floor at the

company’s new facility in Welcome, NC.

JKS Motorsports, which creates logos

and other artistry that decorates stock-

car racing vehicles, placed a bet on pol-

ished concrete as a practical, but

eye-appealing, surface for the com-

pany’s new facility. The process trans-

formed 34,000 square feet of plain gray

concrete into a glistening, reflective sur-

face courtesy of the INDUROSHINE sys-

tem developed by W.R. Meadows Inc.

The facility was a design/build project

by Samet Corp., Greensboro, NC. The

concrete contractor was Triad Construc-

tion Services, High Point, NC. The con-

crete polishing contractor was Blair

Duron, Raleigh, NC.

Casey Chandler, W.R. Meadows’

sales representative in the Carolinas

and Virginia, gives high marks to Triad

for installation of a high-quality, hard-

troweled, water-cured, 3,500-psi con-

crete mix design, providing a sound

basis on which to work some polished-

concrete magic.

Chandler says he was able to make a

case for the polishing process, based on

attributes that include light reflectivity,

durability, slip resistance (impression of

slickness to the contrary), and resistance

to abrasion, oil, and chemicals. A key

selling point was the relative permanence

of the densified and polished concrete.

The polishing process is without a doubt

labor intensive, but should not have to be

repeated if successfully executed.

“With polished concrete, it’s essentially

a one-shot deal,” Chandler says. “You

are changing the composition of the con-

crete, and it’s a permanent solution.”

The project began with initial grinding

to prepare the surface for application of

the liquid sodium silicate densifier, with

45-, 80-, and 150-grit discs used. W.R.

Meadows’ Liqui-Hard densifier was spray

applied, then left in place for a dwell time

of 45 minutes to an hour. Any excess

densifier remaining on the surface was

then removed with water and shop vac-

uum. The next day, the polishing was

completed with increasingly finer dia-

mond grits of 110, 400, and 1,500 sizes.

In some projects, the polishing stage

can progress all the way to a 3,000-grit

stage, but the hard-troweled concrete in

this case didn’t require the finer-grit pol-

ishing, Chandler says.

Chandler concedes that the tech-

niques are “something like an art. You

have to evaluate the conditions and op-

erate sophisticated machinery.”

A final step was applying W.R. Mead-

ows’ Bellatrix, a propriety topical treat-

ment that enhances reflectivity and re-

sistance to staining from oil, grease, and

other petroleum-based substances.

The owner opted to retain the inherent

gray color of the concrete rather than in-

troduce color by means of integral color-

ing of the concrete or field application of

stains or dyes. A 10-inch-wide strip of

solid-color epoxy coating was applied,

however, to floor edges along walls that

were not given the polishing treatment. A

separate edge treatment of this type is

often recommended due to the logistical

limitations of the grinding and polishing

equipment. The burgundy-colored coat-

ing provides contrast—an accent to the

natural color of the concrete surface.

The resulting mirror-like, polished sur-

face stands in marked contrast to the

slate gray of a conventional concrete

floor. For JKS Motorsports, it has the

look of a winning entry.

Gentlemen, start your polishing-ma-

chine engines!

—Joe Maty, J. Maty Communications

Polishing revs up the performance of concrete floor at racecar art shop

7

By Gary Henry,Durability + Design

Editor’s Note: This article was publishedonline in May 2011.

A R E A L G R I N D :Concrete Polishing “101” Offers Multiple Rewards

Participants in the Concrete Polishing Association of America’s Craftsman

Accreditation Course begin grinding the mezzanine-level floor at “Rocketown,” a

non-profit youth facility in Nashville, Tenn.

Photo courtesy Concrete Polishing Association of America

J ust a few blocks from the Country Music

Hall of Fame, Nashville’s non-profit “Rock-

etown” offers young people a drug- and al-

cohol-free venue that includes a concert hall, indoor

skateboard park, and some really old concrete floors.

The facility got “pro bono” help with the floors

March 2011, as two Craftsman-level accreditation

courses taught by the Concrete Polishing Associa-

tion of America (CPAA) swept through, in conjunc-

tion with the Concrete Décor Show.

CPAA instructors Brad Burns, First American

Floor Co., Grapevine, Texas; Roy Bowman and

George Gooch, Concrete Visions Inc., Tulsa, Okla.;

and Derek Mackenzie, Floor Lab, Toronto, Calif.,

taught the back-to-back two-day courses. Reps from

CPAA member companies supported the training

with donated equipment and supplies, including

PROSOCO’s Joe Reardon and 25 gallons of the

company’s Consolideck® LS® (Lithium-Silicate)

Hardener/Densifier.

Along with Rocketown’s aged concrete floors, two

classes of concrete professionals—mostly flatwork

and polishing contractors, Brad said—were the

beneficiaries of the training. Aside from hours of

hands-on training on real-world floors, participants

got classroom training in “The Polishing Process,”

“The Science of Polished Concrete,” “Estimating Pol-

ished Concrete,” and more.

8

Rescuing ‘Abused’ Coffee-Bar Floor The Monday-Tuesday class took on the abused and

deteriorating 2,500-square-foot concrete floor in

Rocketown’s first-floor coffee bar.

Pre-repair work to the floor included treatment

with the lithium-silicate hardener densifier, follow-

ing grinding with 80-grit metals. Husqvarna

GM300 grout went down to further improve the

surface for polishing after grinding with 150-grit

metals. The two treatments did the trick, and the for-

merly soft surface ended with a hard, shiny 1500

resin finish.

The Wednesday-Thursday class faced its own chal-

lenge, Brad said. Participants had to lift some heavy-

duty machines—the STI Prepmaster 2417 and the

HTC 650HDX—with a Skytrack crane to the second-

floor mezzanine overlooking the skateboard area.

Mezzanine Floor Less Daunting The 1,000 square feet of mezzanine concrete was in

much better shape than the coffee bar, Brad said.

Other than location and a thin gray surface coating

that ground off easily, the floor presented no obstacles.

Along with the class participants, Brad said, the

crew at Rocketown and the Concrete Decor Show

were great to work with and helped tremendously.

“Everyone put in long hours and worked ex-

tremely hard to advance the education, benefits and

aesthetics of polished concrete,” Brad said.

The CPAA courses were part of a “decorative

concrete makeover” for the Rocketown youth cen-

ter, carried out in conjunction with the Concrete

Décor Show. The project was the subject of a Dura-

bility + Design story, Opening-Act Preview: Con-

crete Décor Makeover to Transform‘Rocketown.’

For more information about the Concrete Polish-

ing Association’s schedule of classes and registra-

tion procedure, visit the Education page on the

group’s website.

Gary Henry (ghenry@durabilityanddesign.com)

is Durability + Design's managing editor. D+D

(top) George Gooch, left, and Derek Mackenzie spray and spread Consolideck® LS® on aconcrete floor in Rocketown. Photo courtesy of Joe Reardon (above) The Coffee Bar floor at Rocketown gleams after treatment with a lithium-sili-cate hardener/densifier, grouting system and polishing to a 1500-resin finish.Photo courtesy Concrete Polishing Association of America

9

Editor’s Note: This article appeared D+D inNovember 2013.

By Gina R. Johnson,Durability + Design

C O N C R E T E F L O O R I N G : Polished or Coated?Experts go head to head, describing where each treatment shines

T wo formidable flooring options, each with itsown applications and strengths. But whichone, polished or coated concrete, is best for

your particular situation, and what can you expect interms of maintenance, durability and aesthetic options?

10

We invited two long-time practitioners to dis-cuss the differences, along with innovationsand challenges of the trade. Jim Cuviello has been in the concrete polish-

ing industry since 2002. He owns CuvielloConcrete in Stevensville, Md., and is a found-ing member of the Concrete Polishing Associ-ation of America (CPAA). Phil Scisciani founded Specialty Coatings &

Consulting Inc., in Pittsburgh, in 1990. Along with KTA-Tator’s Kevin J. Brown (see

“Polished Need Not Mean Slippery,” page26), they participated in a Durability + Designpanel discussion in January. (View it at dura-bilityanddesign.com/videos.) We picked upthe conversation this fall.

D+D: How do you help an architect, specifieror building owner understand the options?CUVIELLO: We do a lot of AIA presentations,so we start setting the expectations right thereto let them know of what they can expect pol-ished concrete will and will not do. Particularlyif it’s an existing facility, if there’s damage tothe floor, we always tell them a patch is apatch, don’t expect anything different. If there’sexisting tile or glue on the floor, we let themknow that when that stuff is removed and thesurface is polished, any imperfections under-neath or any lines created by tile patterns aregoing to stay there. If it’s a new pour, we let them know that con-

crete has imperfections, that they should ex-pect that the surface when finished is going tobe consistently inconsistent. And again, ifthey’re looking for something perfect, theyshould go buy something that’s manufacturedin a factory with tight quality controls.SCISCIANI: Jim, how much problem do you

run into explaining to people about polishedconcrete? You know, how everyone wants tosee [exposed] aggregate look vs. the cementto cream.CUVIELLO: We let everybody know that

(top) Polished concrete is ideal in retail areas, school corridors, car dealerships, offices, warehouses and certain areas of grocery stores.Photo courtesy of Cuviello Concrete.(middle) In settings where liquids, oils or acidic materials are common, likeat this service bay at a Pennsylvania Honda dealership, experts recommend a coated concrete floor. Photo courtesy of garagecoatings.com.(above) This large commercial laundromat in New York was an ideal candidate for a coated concrete floor. It uses an epoxy coating with decorative flake broadcast into it under a polyurea topcoat. Photo courtesy of garagecoatings.com.

11

there’s three degrees of cut. There’s workingwith the cement paste, which is the concretecream. We can remove the concrete cream andexpose the fine aggregate, the sand aggregate,or we can go further down into it and exposethe coarse aggregate in addition to the sandaggregate in between the coarse aggregate. But when we talk about setting expectations,

flatness numbers are so important. Because ifwe have a low floor flatness, let’s say it’s a 20or 25, the machines, as they travel across thesurface, unless we set the heads up to be ex-tremely flexible, they will end up with incon-sistent degrees of cut. The low spots may becream, the high spots may actually be coarseaggregate; you may have the sand aggregatein between. If it’s on existing concrete, the challenge is if

somebody was walking on the concrete andthey pushed the aggregate down, when wegrind, we may not be able to reach the ag-gregate where it was pushed down. So theseare things that we have to let them know arepossible.What often is painful for them to hear is

they’re paying for the process, not the out-come. We’ll perform the process in the bestpossible manner to deliver the best possible re-sults, but you know, these are things that arebeyond our control and can come up. Now, ifit’s a new concrete pour, we can head a lot ofthat stuff off and make sure that the finishersfinish the concrete in a way that doesn’t createthese problems. [We can] even seed additionalaggregate into the surface to make sure thatit’s consistent. SCISCIANI: As far as [setting client expec-

tations with coatings], I think you have to cometo the architects or building owners and deter-mine what their expectations are for a finishedfloor. And a lot of times it’s, do you recommenda thin-filmed system, a high-build system, ag-gregate or colored-flake system or a quarter-inch resurfacing system. If it’s old concrete, it’s

evaluating what’s the best solution. If it’s newerconcrete, then you go with a thinner system.So it’s really [about] the conditions of the con-crete and what they’re using it for. CUVIELLO: You know, our primary [focus]

for the next year is schools. And I couldn’timagine a school with epoxy throughout all ofthe corridors and all of the classrooms. I mean,I know that there are aesthetically pleasingepoxy systems. I don’t personally see that as agood fit, whereas I think polished concrete is amore decorative application, and that’s a bet-ter fit for like a school system in corridors andin some classrooms. Obviously in laboratories,they might want to go epoxy. SCISCIANI: I agree with you 100 percent

that polished concrete in school hallways andclassrooms are a good fit. But I think when youget into locker rooms, restrooms and kitchenfloors, a decorative polymer floor coating is agood alternative. Old school is to install vinyltile, ceramic or quarry tile in these areas. Dec-orative colored-flake system, which can evencreate a terrazzo appearance, is a good al-ternative. So I think that’s a prime example ofwhere polished concrete and polymer systemswill go hand in hand pretty well.CUVIELLO: I agree. Anytime we see any-

body specifying polished concrete in a lockerroom or restroom or kitchen or food setting, Ialways recommend a seamless epoxy systemthat wraps up on the wall, [for] ease of main-tenance. You know, polished concrete in thebathroom is a nightmare.

D+D: What are some common installationissues?SCISCIANI: On the coating end, if it’s a thin-ner film thickness that we’re putting down, itwill mirror the surface. So if you have concretethat has some pitting and stuff like that, it’sgoing to mirror it. If you go with a coloredflake, one-eighth inch or up, a lot of times itwill mask those issues.

(top) Cuviello notes that it’simportant to set client expec-tations about flatness. A lowfloor flatness can result inuneven degrees of cut, asshown here.(middle and above) As thisNew York project demon-strates, polishing can’t hidecracks, patches and differentconcrete pours. Photos courtesy of CuvielloConcrete.

12

If you’ve got a real damaged floor, thenthat’s when you get into resurfacing. The prob-lem we see with resurfacing is that you’ll gettrowel marks. So, when [setting] customer ex-pectations, a lot of times we’ll say, with theresurfacing material, you’re going to see sometrowel marks; it just happens. If you want asmoother looking floor, then that’s when yougo to a build-up type system.

CUVIELLO: What is getting popular in the pol-ished concrete industry is three-eighths-inch ce-mentitious self-leveling toppings. These toppingsare applied over existing concrete and then pol-ished. We’ve used them successfully, but basicallyit’s going to double the cost of the project. SCISCIANI: What do you do, come in and

blast [the surface] and then put on a three-eighths-inch overlay?CUVIELLO: We come in and basically shot-

blast it. Then we put epoxy down and then ba-sically broadcast sand in it to rejection. Wecome back the next day, clean off the sand re-ally well and then basically put a three-eighths-inch self-leveling material on top. Then wepolish that.We just did an Old Navy where we were

contracted to polish it. Once we got abouthalfway through the process, these footprintscame out of nowhere, the shadowing of all ofthese footprints. Old Navy said “no way,” andmade the contractor basically overlay it, andwe polished it. SCISCIANI: Why do they do an epoxy

coat? CUVIELLO: For vapor barrier, and then also,

when you see the sand, it creates a texture forthat overlay to bond to. SCISCIANI: Interesting. Expensive, but in-

teresting.CUVIELLO: It is expensive. We did two [re-

tail] stores, and, I mean, we’re working in 50-, 60-year-old stores that have been modeledand remodeled and different floorings putdown. Once the flooring came up and we pol-ished the concrete underneath, it was a mess.They kept telling us, patch it, patch it, patch it.We patched it, and for what it was, it lookedgood. In some other areas of the country, [theretailer] said go ahead and put an overlaydown. Now I can tell you what they paid us topatch all of that area; it would have been lessexpensive for them to just go ahead and over-lay it and polish it.

Coating is a good option for improperly cured concrete, a problem polishing can’t hide. Photo courtesy of Cuviello Concrete.

Scisciani used decorative flake polymer coating on a corridor ramp and entryway to match polished concrete corridors. This project was completed at a university in Pittsburgh.Photos courtesy of Specialty Coatings & Consulting Inc.

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D+D: What about maintenance for coatedvs. polished concrete?SCISCIANI: Didn’t we cover this [in the D+Dvideo], Jim?CUVIELLO: We did. I think I crushed you,

too.

SCISCIANI: You did? I wasn’t keeping score[laughing]. You had the better camera angle, too.Once a [coated] floor is put down, there

should be a six- to 12-month maintenance[schedule] — meaning you should have thecontractor or somebody come back in, inspectthe floor. Especially if it’s a floor that has a lotof abuse or is constantly exposed to water.Damaged areas should be repaired promptly,because if the coating’s been damaged, waterwill get underneath and start to break thebond. In a water situation, we recommendevery three to six months. A coated floor should be cleaned, degreased,

either by dry or wet mopping. A floor scrubber,with soft bristles or pad, is also an effective wayto clean. In areas where there’s a lot of grease,a lot of dirt, we recommend they just deck brushit and use a wet vac, depending on the non-skid[treatment] that’s on the floor. CUVIELLO: I think that’s where polished con-

crete really shines, again, in the right applica-tion. For example, with a VCT floor, there’s a costin buying floor finish, there’s a labor cost in ap-plying the floor finish, there’s a labor cost in bur-nishing the floor finish to restore its shine. Nowto maintain polished concrete you still want toburnish it, but instead of burnishing it maybeonce a week, you’re going to be burnishing itonce a month or maybe once every other monthdepending on the amount of traffic. With polished concrete, again, you sweep it

or vacuum it, and then you mop it or autoscrubit or some [other] type of a wet clean process,and then you burnish it. The dry debris removaland the wet mopping should be the sameamount of work no matter what surface it is. SCISCIANI: Good point. That’s where I’m

going to crush you [laughing].CUVIELLO: Bring it on [laughing]!SCISCIANI: No, I agree with you. You

know, D+D did that article on [my work at theFrick Car and Carriage Museum;January/February 2013 issue]. That floor’s

(above) The coated concretefloor of the Frick Car and

Carriage Museum in Pittsburgh looks as good as

new more than a decade afterbeing installed. Wet and drymopping have been the only

maintenance. Photo courtesyof Specialty Coatings &

Consulting Inc.(middle) For a coated floor

subjected to liquid, like thiscarwash at a Honda

dealership in Pennsylvania, Scisciani recommends

maintenance every three tosix months. Photo courtesy of

garagecoatings.com.(bottom) Coated concrete

with decorative coloredflakes can create eye-

catching effects, as at thisKansas church. Using epoxy

with decorative flake broadcast into it and a

polyurea topcoat, the30,000-square-foot floor

features a large compass atthe entrance.

Photo courtesy of garagecoatings.com.

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been down for 12 years, and, other than drymopping and wet mopping, that’s all they’vedone. It still looks like the day we did it. CUVIELLO: Again, I think that goes back to,

with any segment of the floor industry, No. 1,the preparation was done correctly up front.And No. 2, the right product was specced forthe application.SCISCIANI: Right. The environment is foot

traffic and there’s cars sitting on it, so the ma-terial was designed for stain resistance. Andagain, it’s about a 60-mil system, so it’s reallynot a thick system. But for that application, thatwas a properly designed system.

D+D: What about protective treatments —are they necessary for polished concretefloors? CUVIELLO: There’s something in the industrycalled guards. Basically it’s an acrylic-typefloor finish. I would say 90 percent, maybe 98percent of the time, they’re [over-applied].They’re designed to fill in the fractures and themicropores and microfilm on the surface. Butyou know, to put them down that way can bedifficult if you don’t have a lot of experiencewith them. The one thing that I do believe you’re going

to start seeing in the industry is a lot of thesecompanies looking towards the stone indus-try to see how they’ve protected porous stoneover the years. And I believe what we’regoing to start seeing are products that are de-signed to penetrate and protect from withininstead of creating a barrier on top. Becausethe second you over-apply a guard, or mis-apply it, what ends up happening is yourwear surface is no longer the concrete, it’sthat guard. And that’s where this industry hasrun into some problems. SCISCIANI: Kind of like the hybrid polished

concrete look, where some people are [polish-ing the floor and then putting a clearpolyurethane over top of it]? So in a sense it’s a

coated floor, but you still get the polished look. CUVIELLO: Exactly. Penetrating treatments have been around in

the “concrete” industry for a long time, but the“polished concrete” industry has been domi-nated by a product that was designed to pen-etrate and “micro” film on the surface, thinenough you could not tell it was there. Twothings happened within the industry: Contrac-tors over-applied these products and createda heavy film, barrier, coating; and some man-ufacturers’ products did not penetrate as welland laid more on the surface and not in. The Concrete Polishing Association of Amer-

ica at World of Concrete this year came outwith a set of definitions to define the differentways to make concrete shiny. [See “Definingthe Undefinable,” page 40.] SCISCIANI: I think that’s the sad part that I

find with what I’ll call the epoxy floor coatingindustry, is there’s not an organization like theCPAA setting guidelines. I mean [there are] ab-solutely no guidelines in the coating industry. That’s what we fight everyday, trying to fig-

ure out what’s best for the customer, what’sgoing to give them long-term [performance],but yet, what’s going to get us in and out of ajob. We complete a number of floor projectswhere the customer gives us the floor Fridayevening and it has to be ready for use by Mon-day morning. That gives us a very short win-dow, so it limits the materials that we can use. CUVIELLO: The other thing that we run into

— Phil, I’m sure you run into it too — is that thebest product may be too expensive or out oftheir budget. Although the proper specificationfor them is out of their budget, you know, youdon’t want to walk away from the job.SCISCIANI: I’m very careful with that, Jim,

because a lot of times you deal with a customerand then six months down the road they’recomplaining because it’s not performing theway they want. I’ve gone back three or fourtimes to fix a problem where I know it should

Polished Need Not Mean SlipperyIt’s a common misconception: The shine that makes a polished con-crete floor so beautiful, reflecting color and movement, makes it a threatfor slips and falls.In fact, for both wet and dry environments, a polished concrete floor

can be more slip-resistant than a coated concrete floor. According toKevin J. Brown, manager of the commercial services group at KTA-Tator, “The slip resistance of polished concrete actually has a greatercoefficient of friction [COF] than most coated floors considering a typicalspecification for polished concrete.” In general, says Brown, a polished concrete floor has slip resistance that meets or ex-

ceeds industry standards of 0.5 or 0.6 COF. That’s because the flat surface produced bya fine polish puts the sole of the shoe directly in contact with the concrete surface. Thelevel of slip resistance depends on the concrete polishing specification — the level ofhoning and polishing that’s done and the grit level of the tooling used. Protective film-forming acrylic coatings that are burnished into the surface, aka

“guards,” can also be a problem when over-applied or misused. “They’re used to makethe floor pop and shine — and they do,” says Brown. “But they can make the slip resist-ance of the floor much less than if not applied, especially when [the floor is] wet.” Trouble also can arise when maintenance procedures aren’t followed, for example, if

janitors wax a polished floor to enhance its appearance. Wax can be problematic for slipresistance. Manufacturers typically recommend a mild, neutral-pH cleaner. Entry matscan help to trap dirt and water from being tracked onto the surface. And of course, it’s im-portant to clean up any spills immediately.

A variable incidence tribometer is used to measure the coefficient offriction on polished concrete.Photo courtesy of KTA-TatorInc.

Kevin Brown, KTA-Tator

have been an eighth-inch system, a doublebroadcast system, but they only wanted to payfor a sixteenth-inch system. So now I’m kind ofstuck under warranty, even though I told themup front, we need to do it this way. It’s one ofthose jobs I probably should have walkedaway from.

CUVIELLO: It is a very, very slippery slope towalk, and when we do it, we make sure wecross our t’s and dot our i’s and overempha-size everything and document everything. Gina R. Johnson (gjohnson@durabilityand-

design .com) is editor in chief of Durability +Design. D+D

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Editor’s Note: This article appeared inD+D in January 2012.

By Walter Scarborough, HALL Building Information Group, LLC

Crunching the Numbers on Polished Concrete, Other Flooring Types

P olished concrete has gained a great dealof traction in design and construction,thanks to the technology’s quickly-

earned reputation as a sustainable, durable andaesthetically appealing flooring option.

A combination of dyeing and polishing produced the color and shimmer of the concretefloor surface of the Rothwell Student Center at the University of Wisconsin’s SuperiorCampus. The color was supplied by an acetone dye in “Inca Gold,” while PROSOCO Inc.’sConsolideck® LS® Hardener/Densifier was used in the polishing process. A micro-thinprotective coating of Consolideck® LSGuard®, applied with high-speed burnishers,gave the floor extra protection and gloss. Collaborating on the project were SpecializedInc. and D&B Industrial Floor Coatings, both based in Wisconsin.Photo by Shawn Wardall, Specialized Inc.

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But how does polished concrete stack upagainst other flooring solutions in the big pic-ture of economics and performance, whenconsidered in terms of long-term cost andmaintenance issues?Polished concrete—more specifically,

bonded abrasive polished concrete—has be-come amazingly popular in recent years, withexplosive growth in its use in virtually everybuilding type, both residential and commer-cial. Polished concrete is favored by manybuilding owners and design professionals inlieu of traditional applied floor coverings.A number of reasons can be cited as to why

polished concrete is favored, but two reasonsfrequently are seen at the top of the list.First, among the various flooring solutions

available, polished concrete is one of the leastexpensive flooring systems over the service lifeof the floor.Second, a perception exists that there is no cost

for maintenance when compared to terrazzo,vinyl, carpet, and ceramic tile. Many buildingowners and design professionals believe that pol-ished concrete floors are maintenance-free andthat the polished finish will last indefinitely.Unfortunately this is not entirely true. This be-

lief results in frustration when a polished con-crete floor appears to lose its luster.

This matter of maintenanceWhile much has been written about specifyingand installing polished concrete floors, not muchhas been said about the necessary maintenance.So, what exactly is the cost of polished

concrete?While the initial cost is typically less than most

other flooring solutions, this is only part of theevaluation when considering the life cycle offlooring solutions. The other part of the equa-tion, also of significant importance to manybuilding owners, is the cost in terms of actualexpense, along with attention and effort re-quired to maintain the polished concrete floor.As for the prevailing misunderstanding that

polished concrete is maintenance-free, itshould be emphasized right at the top thatthere is no such thing as a flooring solution thatrequires zero attention.To effectively evaluate the maintenance cost

of polished concrete, we should look at theother common floor coverings and their main-tenance costs.It is difficult to develop a single general cost

for every floor covering because of variationsconnected to location, building type, quality offloor coverings, traffic volume, attention tomaintenance, and all the things that happenon or over a floor.One of the most extensive studies of initial

and maintenance cost of floor coverings wascarried out by the National Terrazzo Manu-facturers Association (NTMA) and publishedas the Terrazzo Cost Calculator.According to NTMA, this study was based

on a survey of a number of buildings acrossthe U.S., and it used a typical corridor in acommercial building as the basis of evaluation.The country was divided into eight zones inorder to localize the cost, so the range shownin the charts below is least cost to most cost,based on the zones.For purposes of simplicity, the information

presented below only extends through 10

It is difficult to arrive at asingle general cost for everytype of floor covering.

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years of the life-cycle cost.While polished concrete was not included in

the NTMA study, there are other sources of costfigures that can be cited in order to make acomparison, as shown here.Three impacts on floors dominate the con-

cerns of most owners: scratches, stains and lossof sheen. Dust, dirt and fine grit can act assandpaper when people walk on the floor orwhen wheeled carts are moved across thefloor. This action creates small scratches thatdull the finish of every floor type—no flooringsolution is immune.Over an extended period of time, this dulling

process accumulates, and if the floor is notmaintained, an unsightly appearance may re-sult, especially if a shine is important to thelook of the floor. If not dealt with on a routinebasis, damage can occur and, depending onthe flooring type, replacement or restorationbecomes necessary.

Maintenance comparisonsNow let’s take a brief look at the requirementsfor maintaining the various floor coverings thatwere included in the NTMA study. This infor-mation is generalized because, like cost, manyvariables influence the amount of maintenanceattention that is necessary.For example, floors immediately adjacent to

entrances will require more attention thanfloors in more remote areas. Floors in a popu-lar department store will require more atten-tion than floors in a dentist’s office. Paths tendto develop across floors due to objects such asshelving units that channel foot traffic in spe-cific directions.To achieve the maximum life of a flooring fin-

ish or covering, several proactive activities areessential to have in place.First, it is important to have a maintenance

plan in place that is specifically designed forthe flooring type, the amount of traffic that will

These costs were compiledfrom the following sources:Concrete Polishing Association of America; TitusRestoration; and ConcreteNetwork

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cross the floor, and the daily activities that willoccur over the floor.Second, while all stains cannot be prevented,

it is essential that when a spill does occur it is re-moved immediately and the affected areacleaned. If spills are not removed promptly, thefloors become unsightly and more aggressive re-moval or restorative methods may be necessary.Third, it is prudent to use walk-off mats at

building entrances and other locations to pre-vent dust, dirt and fine grit (particulate) frombeing brought onto the floor.Terrazzo: While epoxy terrazzo does not re-

quire a sealer, Portland cement terrazzo re-quires a water-based acrylic sealer to protectthe exposed Portland-cement portion of the ma-trix, which is about 30% of the exposure. NTMAprovides the following minimum recommenda-tions for maintaining terrazzo floor finishes.• After initial installation: While not requiredfor wear protection, as an option NTMA sug-gests a high-luster finish on top of the sealer toachieve a desired sheen. These normally re-quire the added expense of spray-buffing tomaintain the sheen.

• Daily: Sweep using a yarn-wick brush treatedwith sweeping compound, along with handworking of stubborn stains and scuff marks withneutral cleaner diluted in warm water.• Weekly: Damp mop lightly soiled floors withneutral cleaner. Heavily soiled floors should bescrubbed with a mechanical buffing machineand neutral cleaner. Residue should bemopped up with clean water before it dries;this is allowed to dry, followed by buffing witha dry brush.• Semi-annually: Strip old sealer and any fin-ish coats. Reseal a clean floor.Vinyl: A major vinyl sheet and tile manufac-

turer recommends the following general main-tenance procedures.• After initial installation: Sweep, dust mop orvacuum to remove loose dust and dirt. Removedried adhesive residue with mineral spirits.Damp mop with a neutral detergent. Applytwo coats of a high-quality commercial floorpolish; a high-quality stain-resistant sealer be-neath the polish should be considered in areasof high traffic, high soil load and areas wherestaining potential is high.

Dust is one of the most significant problems withmaintaining floor finishes.

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• Preparation for commerciral traffic: Scrubwith a neutral detergent solution and a scrub-bing pad or equivalent brushes. If badly soiledand/or scratched, strip the finish with a strip-ping solution. Thoroughly rinse the floor withfresh, clean water and allow it to dry. Applythree to five coats of a high-quality commer-cial floor polish; a stain-resistant type shouldbe considered in areas of high traffic, soil loadand staining potential.• Daily/regular: Sweep, dust mop or vacuumdaily to remove dirt, grit and soil that candamage the floor and become ground into thesurface. Damp mopping should be performedon a regular or daily basis depending uponthe traffic and soil levels. A neutral detergentcan be used.• Periodic: When needed, scrub the floor witha neutral detergent using a single-disc (300rpm or less) or automatic floor machine andthe appropriate scrubbing pad or equivalentbrushes. If using a single-disc floor machine,remove dirty cleaning solution with a wet vac-uum or mop. Thoroughly rinse the floor withfresh, clean water and allow to dry. If sufficientpolish (three to five coats) remains on the floor,buff, spray buff, or burnish to restore gloss. Ifneeded, additional coats of floor polish maybe applied.

• Restorative maintenance-stripping: Scrubwith a diluted stripping solution using a single-disc floor machine equipped with a scrubbingpad or equivalent scrub brush. Remove thedirty stripping solution with a wet vacuum ormop. Thoroughly rinse with fresh, clean waterand allow it to dry. Apply three to five coats ofa high-quality commercial floor polish; a stain-resistant type should be considered in areas ofhigh traffic, soil load and staining potential.Carpet: The Carpet and Rug Institute (CRI)

sees a big difference between cleaning andmaintaining carpet. Cleaning is the removal ofapparent soil, and maintenance is a scheduledongoing process of soil removal designed tomaintain the carpet’s daily appearance at aconsistent level of cleanliness. CRI suggests acustomized, comprehensive carpet-care pro-gram that consists of the following five elements:• Soil containment: Isolation of soil enteringthe building using mats at entrances.Vacuuming: Scheduled frequency, usuallydaily, for removal of dry soil using a CRI-ap-proved “Green Label” vacuum.• Spot and spill removal system: Using profes-sional spot removal techniques.Interim cleaning: Scheduled-frequency ap-pearance cleaning for all traffic areas.• Restorative cleaning: Scheduled-frequencydeep cleaning to remove residues andtrapped soils.Porcelain tile: Porcelain tile is unique be-

cause of its high density and low water ab-sorption attributes, which means it does notusually require sealers or waxes (actually, sur-face coatings may negatively affect the per-formance of the tile).• After initial installation: Completely removegrout residue and construction dirt.• Regular maintenance: Most tile manufactur-ers recommend a regular maintenance routineconsisting of the following steps.— Remove debris from the tile by sweepingwith a soft bristle broom or vacuuming.

Cleaning a sheet vinyl floorwith soap and an automaticfloor machine.

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—Spills should be wiped up as quickly aspossible.— Apply cleaner to tile and allow cleaner toremain on the tile for a short period of time.For unpolished tile, scrub with a nylon pad orsoft bristle brush, or for more heavily soiledfloors use a floor machine equipped with anylon pad or bristle brush. For polished tile,wipe or mop with a nonabrasive mop or cloth.— Remove the dirty cleaning solution and

water with a wet vacuum or mop. Thoroughlyrinse with clean water and remove with a wetvacuum, mop, or towel.

Polished concreteContrary to the prevailing perception, a pol-ished concrete floor does require some main-tenance attention during its service life.Polished concrete is not indestructible, nor

can it be maintenance-free throughout its use-ful life. The consideration of primary impor-tance is that polished concrete floors do notrequire the magnitude of maintenance atten-tion that other floor coverings command.If maintained properly, polished concrete

floors should provide years of satisfactory per-formance under whatever conditions prevail.A prominent concrete-polishing and pol-

ished-concrete restoration company with a na-tional reputation gives the following generalrecommendations for maintaining polishedconcrete floors. It should be noted that theseare only general recommendations; each pol-ished concrete floor requires a specific main-tenance program that is suited to thatparticular floor.• After initial installation: As an option, the fin-ish on polished concrete floors can be pro-tected by a stain guard, which can be asacrificial layer; this will protect the floor fromscratching, mild acids, spills, and stains.Daily: Dust mop; depending on the volume oftraffic the floor may also need to be wet-mopped or autoscrubbed. Spills should be re-moved immediately and the floor cleaned. Forexample, if not removed immediately, acidicfood spills such as pickle juice or tomatoes cancut through the stain guard and damage thepolished concrete floor surface.• Weekly: Mop or autoscrub with clear water.• Monthly: Mop or autoscrub with clearwater; using a neutral-pH soap if needed andrinsing after.• Quarterly: Mop or autoscrub with clear

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water; using a neutral-pH soap if needed andrinsing after.• Annually: Mop or autoscrub with clearwater; using a neutral-pH soap if needed andrinsing after. Optionally, high-speed burnishusing a diamond-impregnated maintenanceburnishing pad.• Three years: Mop or autoscrub with clearwater, using a neutral-pH soap if needed andrinsing after. This may be the time to apply astain guard and burnish with a high-speedburnisher using a high-grit diamond-impreg-nated burnishing pad.• Five years: This may be the time to repolishwith high-grit bonded abrasives. Mop or au-toscrub with clear water; using a neutral-pHsoap if needed and rinsing after. Apply addi-tional coats of a stain guard and burnish witha high burnisher using a grit diamond im-pregnated burnishing pad.Throughout the life of the polished concrete

floor, it is relatively simple to rejuvenate thefloor by applying additional coats of the stainguard, burnishing or repeating the last coupleof steps of the polishing process using fine-bonded abrasives.

It’s complicatedWe hope this article has provided a generallook at how bonded abrasive polished con-crete floors compare to other flooring solutionsin initial cost and maintenance. As stated atthe outset, each floor is located in a unique set-ting and a maintenance plan should be estab-

lished that takes into account how the floor willbe used and the level of use anticipated.

About the author Walter R. Scarbor-ough, CSI, SCIP,AIA, is Dallas re-gional manager ofCharlotte, N.C.-based HALL BuildingInformation GroupLLC, and offers specifications consulting, man-ufacturing consulting, and peer reviews. He isa contributing editor of Durability + Design,and is a registered architect and specifier withmore than 30 years of technical experiencewith many building types. He was director ofspecifications for 10 of his 22 years with oneof the largest architecture firms in the world.Scarborough is revision author for CSI Proj-

ect Delivery Practice Guide; co-author of thecollege textbook Building Construction, Princi-ples, Materials and Systems; has written arti-cles for periodicals; has taught college courses;has given presentations at local, state, re-gional, and national conferences; is active inthe Construction Specifications Institute at na-tional and chapter levels; is a past president ofthe Dallas CSI chapter; is a member of the In-stitute Education Committee; has CDT, CCS,and CCCA certifications from CSI; receivedCSI’s J. Norman Hunter Memorial Award in2008; and is an ARCOM MasterSpec Archi-tectural Review Committee member. D+D

Depending on usage, polishedconcrete may need to beswept daily.

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Editor’s Note: This article appeared onlinein February 2012.

By Howard Jancy, Jancy & Associates

A R T I S T R Y A N D C H E M I S T R Y :Color Theory and Practice with Polished Concrete

Almost two decades ago, coloredconcrete flooring found its wayinto the lexicon of architects and

interior designers. As topical concrete color-ing was rediscovered, designers realized thata dull and lifeless-appearing concrete slabcould be enlivened with natural colors andimaginative tooling.Today, topically coloring concrete floors re-

mains in vogue, but the popularity of mechan-ically processed or polished concrete has

emerged as a major force in current ap-proaches to the coloring and treatment of hor-izontal concrete.Chemical stains are utilized, in addition to

dyes with their wide range of colors, for color-ing polished concrete floors. Even though top-ical coloring technology is well known,understanding the qualities of the availablecoloring products, as one of the many impor-tant components of polished concrete, is im-portant to managing expectations.

This standard gray concrete slab is polished and colored with water-based dyes.Photo courtesy Decorative Concrete Institute

The materialsThe two most common topical coloring prod-ucts for concrete are chemical stains and dyes.Each system offers a unique palette of colorsand to a degree, yield similar results—translu-cent, variegated and mottled colorations—often compared to the natural color variationsfound in stone or other natural materials.Chemically reactive stains react with the ce-

ment in the concrete to form a limited numberof earth-tone colors. The coloring reaction,which is often unpredictable and surprising,even with the construction of a pre-job mockup, can differ across the concrete’s surface, po-tentially creating a high level of color variation.In contrast, dyes are pigment concentrates

mixed with water or acetone, and are not de-pendent on the concrete’s chemistry to producecolor. Since dyes do not react with the concretesubstrate, results are more consistent and truerto the color chart, which some may consideran advantage over reactive stains.Though some of the earth-tone colors avail-

able from dyes are visually similar to thoseproduced with acid stains, more colors—par-ticularly vibrant color choices—are availablewith dyes. Not all dye colors and products are

UV stable, so applications near windows andskylights are potentially problematic.Some manufacturers provide dyes with UV

stabilizers or a densifying dye (color and den-sifier combined into one product) to enhancecolor longevity. The practicality and effective-ness of these color-stabilized systems shouldbe discussed with the contractor and supplier.Reactive stains and dyes are used on existing

and newly installed concrete floors. On proj-ects where a new concrete floor will be in-stalled and polished after curing, anothercoloring option is a coloring admixture addedto the concrete during mixing. Providing somecolors similar to the stains and dyes, integralconcrete coloring offers advantages over top-ical coloring agents, such as shortening thetime required to polish the concrete and im-proved color durability.

Choosing the colorFor the most part, contractors initially supplycolor charts and project photos to illustrate thevarious color options. Once color choices aredetermined, often dictating the possible productalternatives, contractors will typically discussthe pros and cons. This is key to managing ex-pectations of the selected system relative to thedesired project outcomes. Contractors’ insightson product selection are often based on per-sonal preference and experience, yet there is acommon thread of opinion from polishing con-tractors we spoke with for this article.

New concreteWhen installing a new concrete floor, integrallycoloring the concrete during mixing is preferredover topically coloring the concrete during thegrinding and polishing process. Once a color-ing admixture is added to concrete, it requiresno additional labor to install, whereas topicalstains and dyes require additional labor toapply and remove residues. Integral concretecolors are also considered more durable rela-

The Bartow County Civic Center in Cartersville, Ga.,features a polished and dyedconcrete floor installed byCSolutions (Norcross, Ga.)Photo courtesy American Society of Concrete Contractors

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tive to UV exposure and heavy use or traffic,since the color is full depth, compared again tostains and dyes, which concentrate color onlynear the concrete floor’s surface.Another consideration for using integral

color for new concrete is ease of repair. Topi-cally applied colors do not penetrate deeplyinto the surface; even moderate scratches mayremove the color, making repairs more chal-lenging (particularly if using an acid stain)compared to the full-depth color provided byan admixture. So, integral color can save timeand money when installing, processing andmaintaining the polished concrete floor.

Existing concreteFor an older concrete floor in good physicaland visual condition, acid stains and dyes arethe product choices. Generally, chemical stains

are only available in eight to 12 colors,whereas dyes offer a wide range of colors, in-cluding many bolder and brighter hues. Evencustom colors are possible with dyes.Once a color is chosen by a project owner,

contractors will review other considerations asto the best product (remember managing ex-pectations), particularly if the color choice isavailable as either an acid stain or dye.The contractors we spoke with tended to be in

agreement that chemically reactive stains aremore durable than pigment-based dyes. Hard-ened concrete contains numerous small pores.Mechanically processing concrete opens thepores at the surface, allowing the topical colorto penetrate, and depth of penetration is solelya function of the concrete’s natural porosity andhow well the surface has been opened bygrinding and honing. At this point stains anddyes tend to penetrate equally well.When the chemically reactive stain is ap-

plied, however, it reacts with the calcium hy-droxide, produced during cement hydration tocreate the color. Consequently, the resultingcolor is “fixed,” or bound in the concrete porestructure, contributing to its durability.Dye colors, on the other hand, are formed

by pigment that is retained in the concretepores after the water or acetone carrier dissi-pates. The pigments are not as strongly boundas a stain color, not only making the colormore susceptible to degradation from traffic,but also to rising moisture vapor. On a heavilyused commercial floor, an acid stain might bethe preferable coloring product and process.It should also be kept in mind that issues with

UV stability must be considered in weighing dye-ing versus staining. Acid stains are great prod-ucts, but they are not without their quirks. Asalready mentioned, depending on the concrete’smix design and chemistry, a stain color can ex-hibit considerable variation, sometimes faintlyresembling the color chart or the result achievedon a previous installation. Stains are UV stable.

An acetone-based dye in anamber color was applied tothis floor with a hand-pumpsprayer. Acetone-based dyeswere used, instead of water-based dye or acidstain, because acetone evaporates quickly, eliminating color bleedingunder painters’ tape.Photo courtesy Superior Polished Concrete LLC

25

Green and blue stains, however, are proneto darkening, even to the point of turning blackwhen repeatedly exposed to moisture. Thiscould be a problem for the floor area under adrinking fountain, near a sink or toilet, or evenfrom periodic wet mopping, if the floor is notsealed and maintained.Once an acid stain is applied, most manu-

facturers recommend a dwell-time of severalhours for the stain to react completely to cre-ate the desired color. Multiple applicationsmay even be necessary to attain an approx-imation of the color chart. Often, the stainresidues must be removed from the surfacefor an accurate evaluation of the color beforedetermining if additional stain is needed onthe floor.

Stain residues should also be removed priorto polishing so as not to diminish the effective-ness of the resin-bonded diamond abrasives.Stain applications are potentially more time-consuming and labor-intensive than a compa-rable dye application, adding to the cost andduration of a project.Dye products dry quickly, so evaluating the

coloring effect is rather quick, as is application ofmore dye if needed. Dye residues are alsoquicker and easier to remove than stain residues.

Using stains and dyes togetherInterestingly, many contractors will utilize bothchemical-stain and dye products on the sameproject. Often, a stain may yield an unsatis-factory result on portions of the floor, and adye of the same color will be used to touch upthe marginal stain color. Another opportunityfor dual use is on a previously stained floorthat now requires recoloring.Imagine a food spill—vinegar, pickles,

tomato sauce—on a polished concrete floor ina grocery store. Thorough cleaning will notonly remove some of the stain color, but alsomay render reapplication of a chemical stainineffective since there is now insufficient cal-cium hydroxide in the concrete to initiate achemical stain reaction. Here again, a dye is alogical choice for the repair.What about water-mixed dye compared to

an acetone-mixed dye? Again, many goodopinions are heard on this question, and allcarry validity, depending on the job. If indoorair quality and flammability are a concern,then the obvious choice is a water-based sys-tem. If the environmental concerns are not anissue, then acetone-mixed systems offer manyadvantages, for the following reasons.• Acetone “flashes,” or evaporates quickly, al-lowing for quicker evaluation and reapplica-tion of the dye prior to polishing.• Rapid evaporation minimizes the risk ofcolor bleeding across a saw-cut joint or under

AmeriPolish dyes were usedto create this multi-coloredpolished concrete floor.Photo courtesy AmeriPolishInc.

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masking tape into the adjacent surface wheninstalling logos, graphics, grid patterns, andsimilarly detailed compositions.• Acetone is less dense than water, so it mayact as a better carrier for the pigments into atightly closed concrete surface.• Acetone readily penetrates through stain-guard products and sealer residues in the con-crete’s pores, making the dye more effective forrepairs and touch up• Acetone dyes produce slightly darker colorsthan water-based dyes of the same color.Other solvents such as alcohol or lacquer

thinner may also be useful. These types of sol-vents would be used since they evaporate moreslowly than acetone, potentially allowing thepigmentation to penetrate deeper into the con-crete’s surface pores.Regardless of the topical coloring product cho-

sen, the colorations produced by acid stains anddyes can look different, depending on the colorof the substrate. Concrete can range in appear-

ance from light to dark gray. Self-leveling over-lays also are available in white and light gray.Also, when grinding aggressively and signifi-cantly exposing the aggregate, the aggregatecolor will alter the perceived color of the stainor dye. A mock-up is always advisable to de-termine the substrate’s effect upon final color.

Problem concreteFloors that are in good physical and visual con-dition are the best candidates for processing ofconcrete with coloring and polishing. Some ex-isting concrete floors may not be effectivelytreated; this may include concrete floors thathave been excessively patched or trenched,were constructed with different concrete mix de-signs, exhibit random wear patterns, were in-consistently finished during original installation,or show shadows from prior contamination.These surfaces will yield less-than-satisfactoryresults when colored and polished.For these conditions, a viable option is resur-

AmeriPolish dyes were used to create this polished concrete floor.Photo courtesy AmeriPolish Inc.

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facing the floor with a cementitious overlay,typically installed at a thickness ranging fromone-fourth to three-eighths of an inch, andonce cured, proceeding with mechanical pro-cessing. Overlays are pre-packaged products,generally are available in a white and lightgray color, and can be integrally colored ortopically colored with a stain or dye.Also, decorative-mineral aggregate or col-

ored recycled glass can be incorporated intothe overlay, exposing the colorful additionsduring polishing.It should be noted that the existing concrete

must be thoroughly prepared before installingan overlay. Again, the owner, designer orspecifier should consult with the supplier andcontractor, since not all overlays are alike.Some products may be more suitable than oth-ers when coloring and polishing.

The challenge of managing expectationsThere does not seem to be one coloring prod-uct that will perform ideally on every job. Theanswers are not always black and white;sometimes there are gray areas, even with pol-ished and colored concrete floors. But by un-derstanding the similarities and differencesbetween the various coloring materials, colorand product selection can be a more informedand accurate process giving you confidencethat your colored polished concrete floor willmeet your expectations.

References1. Out of the Stone Age: The Evolution of Dec-orative Concrete Continues to Stretch the Hori-zons for an Ancient Building Material, byHoward Jancy, D+D News, July 2010.2. Concrete Stains and Dyes: Surveying theColor Spectrum, by Howard Jancy, Journal ofArchitectural Coatings, March-April 2009.3. Nine Fundamentals for Polished Concrete

Floors, by Jason Barnes, The ConstructionSpecifier, August 2011.

About the author Howard Jancy, CSI,CDT, is president ofJancy & Associates, anarchitectural-consultantand manufacturer’s-representative firmbased in Chicago. Hehas more than 22 years of experience in thedecorative-concrete business, in sales, train-ing, technical service, architectural promotion,specifications, technical writing, and new-product and business development. Jancy &Asssociates provides representation for build-ing-material manufacturers and specialty con-tractors, creating greater visibility within thedesign community and opportunities for in-creased sales.Jancy is a member of the CSI Chicago chap-

ter and is chairman of the chapter’s IndustryRound Table, which offers professional-devel-opment seminars for members. He conductsan annual class about AIA-compliant pro-grams for architectural continuing education.He has written articles for a number of indus-try publications, including Concrete Decor,Landscape Contractor National, Journal ofArchitectural Coatings, Construction Specifier,and Concrete Construction.Jancy has a bachelor of science degree from

the University of Illinois, is an ACI certifiedConcrete Technician, and is certified by CSI asa Construction Documents Technologist (CDT).He was a founding board member of the Dec-orative Concrete Council and has been an af-filiate member of the National Ready MixConcrete Association (NRMCA), the AmericanSociety of Landscape Architects (ASLA), Amer-ican institute of Architects (AIA), and the Amer-ican Concrete Institute (ACI). D+D

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Editor’s Note: This article appeared onlinein September 2012.

By Howard Jancy, Jancy & Associates

K E E P I N G T H E S H I N E :Basic Training in Maintenance of Polished Concrete Floors

H ellooooo! Is anybody listening? Too often, I hear myself saying

that when, for the umpteenth time, I am discussing the mainte-

nance requirements for a polished concrete floor with an owner

and his or her representatives.

Previous discussions—forgotten, ignored or selectively applied—have

evolved into a job complaint, with accusatory fingers pointing at the con-

crete, at the polishing equipment, at the chemicals, or at the contractor.

So now, for the umpteenth + first time, let’s again discuss polished con-

crete maintenance.

Photo courtesy of Metzger/McGuire

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What Is Polished Concrete?Suitable for older concrete, as well as newlyplaced or constructed floors, polished concreteis the product of mechanical processing andchemical treatments.The mechanical process is a series of stages

referred to as grinding, honing, and polishing(GHP), progressing from coarser to finer dia-mond abrasives appropriate for each stage ofthe process.The goal of progressing to finer grits in each

stage is to achieve maximum refinement; thatis, to remove the scratch or abrasive marks in-troduced by the coarser grits. In simple terms,GHP processing levels prepare, smooth and fi-nally shine concrete flooring.The processed concrete is chemically treated

with a liquid hardener to enhance its surfacedurability, reflectivity and gloss. It is a critical

application that positively contributes to theaesthetic longevity of the floor. A protectivemicro-film can also be applied for stain resist-ance and cleanability.

Stages and StepsGrinding with metal-bond, 50-grit or lowerabrasives is the most aggressive stage, open-ing the surface and removing minor pits andblemishes, some stains and sealer residues.Grinding is also used to expose the sand andlarger aggregates near the concrete surface, ifthat is the desired look for the finished floor.Grinding can be thought of as preparation for

honing and polishing, physically opening theconcrete floor to a desired level, thereby creat-ing a range of appearances, from a sanded orsalt-and-pepper appearance up to a coarse ag-gregate appearance similar to terrazzo.Honing utilizes resin-bond abrasives, rang-

ing from about 100 to 400 grit. During thisstage, the finer or less-aggressive abrasives incomparison to the grinding stage start to closethe concrete surface, imparting a matte finishwith a degree of reflection and sheen. This isalso when a liquid hardener or densifier is ap-plied, generally after the surface has beenprocessed with a 200-grit abrasive.Finally, polishing is undertaken, using abra-

sives from 800 to 1500 grit—and sometimesas fine as 3000 grit—to achieve a highly re-flective floor with mirror-like qualities.The liquid densifier reacts chemically within

the surface pores of the concrete, producing aharder, denser surface that is more resistant toabrasion, dirt and some spills. The densifieralso enhances the sheen produced by me-chanical processing.Finally, a guard product (also called a stain

protector) can be applied to further protect thefloor from ketchup, vinegar, red wine, motoroil, anti-freeze and other common, damagingmaterials found in commercial buildings.When applied correctly, guard products form

Photo courtesy ofMetzger/McGuire

an imperceptible micro-film in the surface poresof the concrete that improves resistance to dirtand stain absorption. While the products areeffective against wet spills that could stain oretch the surface, they are also breathable, al-lowing moisture vapor to leave the slab.

Concrete ConundrumMisunderstanding the maintenance require-ments of polished concrete and putting the re-sponsibility in the hands of those leastinformed about the technology are generallythe root causes of a dull and lifeless floor.Polishing concrete is a very specific process.

It should follow, therefore, that maintenance isalso a specific process requiring the rightequipment, chemicals, timing, and a basic un-derstanding of concrete.Cured concrete has the strength to support

tall buildings or carry cars and trucks on aroadway; yet it also has an Achilles heel thatis often exhibited on polished floors: Hardenedconcrete is a reactive material. Spill or misap-

ply a highly alkaline or acidic liquid (whethera food or the wrong cleaning chemical), andthe perfectly polished surface will be dulled,etched, stained or even damaged.Equally vexing is gritty material carried on

the bottom of shoes, which scratches the floor.On the other hand, ignoring or minimizingmaintenance will also diminish the floor’s at-tractiveness over time. So the facility ownerand cleaning personnel need upfront educa-tion about maintenance requirements.Reviewing a maintenance manual is an ideal

way to start a dialogue about how to conducta maintenance program for polished concrete.The table below, or some variation, might be

a central feature of a maintenance manual.

Maintenance MatrixDaily maintenance is important for high-trafficcommercial floors, although residential floor-ing may require less frequent care. The basicrequirement of daily care is sweeping and dry-mopping to remove dirt and grit that dulls the

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Sample Maintenance Schedule for a Polished Concrete Floor

surface and, if left there, can even scratch orabrade the concrete over time.Excessive scratches or deeper gouges could

require more time and labor to correct, so dailyattention to the floor can pay off longer term.(On a preventive note: Walk-off mats at en-

trances or protective mats where there is con-centrated foot shuffle, such as behind a servicecounter, are highly advisable. This is especiallyimportant in Northern climates, where salt andsand are used to remove ice and to preventslip-and-falls.)Weekly maintenance includes wet mopping,

which may be required more frequently, de-pending upon use of and traffic on the floor.Manual mopping using a mop and bucket is ap-propriate for small or select areas of a largerfloor, whereas larger floors, such as those foundin box stores or warehouses, are best “mopped”with a walk-behind powered scrubber.Frequent water changes are important when

hand mopping. Dry mopping or vacuumingshould always precede washing the floor.

The Right SolutionThe pH of the cleaning solution is importantwhen wet-cleaning a polished concrete floor.Many cleaning chemicals typically used to

maintain other types of flooring are inappro-priate for polished concrete.So the choice of cleaning products is critical:

Avoid anything acidic or highly alkaline, andsubstitute pH-neutral to slightly alkaline cleaningproducts. Your manufacturer or supplier of pol-ished concrete chemicals will often have specialtycleaning products designed for these surfaces.Conversely, using only water to clean pol-

ished concrete can lead to problems in time.Neutral detergents contain surfactants or wet-ting agents that help the cleaning solution pen-etrate the dirt and, most importantly, keep thedirt suspended in solution, allowing it to bemore readily removed. Using water alone mayallow the dirt to redeposit on the surface as thewater dries.Educating cleaning staff about using appro-

priate cleaning methods and chemicals for pol-ished concrete is important.

Keeping UpWet spills of damaging foods and other sub-stances should be cleaned up as soon aspossible.The guard product/stain protector applied

after mechanical processing provides onlyshort-term (hours) protection from these typesof spills. Left overnight, the spilled material canpenetrate and blemish the concrete. Remem-ber, guard products do not create an impervi-ous film and are not intended to be sealers.Periodic dry and wet cleaning is the basis of

the cleaning program. But even if the cleaningis done regularly, the polished surface can dull.To re-pop the shine, run a high-speed (1500rpm) burnisher over the floor once or twice amonth with micro-polishing pads that are im-pregnated with fine-grit diamond abrasives.This process should be done only after the flooris thoroughly cleaned of dust, dirt and grit, andthen dried.After a point, however, even high-speed bur-

nishing may not revive the polished concrete

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Photo courtesy of Jancy &Associates

to its original luster. At this time, re-applicationof the guard product may be necessary. Theguard is applied to a clean and dry surfaceusing a micro-fiber, T-bar applicator.Do not apply excessively, creating a sealing

effect with the material. It is also important tonote that the chemical composition of guardproducts or stain protectors, as well as liquiddensifiers, vary among manufacturers. Consultwith the manufacturer or supplier of the chem-icals before embarking on a maintenance reg-imen for your polished concrete floor.

Diamonds are ForeverDiamond polished floors are almost forever, ifthey are properly maintained. However, thefloors could require rejuvenation every two to10 years. The frequency or necessity is obvi-ously dictated by the amount and type of traf-fic, and by the original finish, whether it ismatte or mirror-like.Traffic over the polished concrete will even-

tually dull and scratch the surface beyond theremedial capabilities of burnishing and re-ap-plication of the guard product.Rejuvenation involves mechanical process-

ing, similar to the initial GHP process. You’relikely not starting with aggressive grinding, butrather with honing or polishing, depending onthe scratch depth into the concrete. Rejuvena-tion will also require re-application of the den-sifier and micro-filming guard product. Oncethe rejuvenation is accomplished, the polishedconcrete floor is attractive and functional foranother 10 years.

About the authorHoward Jancy, CSI, CDT,is president of Jancy &Associates, an architec-tural-consultant and man-ufacturer’s-representativefirm based in Chicago.He has more than 22 years of experience in

the decorative-concrete business, in sales,training, technical service, architectural pro-motion, specifications, technical writing, andnew-product and business development. Jancy& Associates provides representation for build-ing-material manufacturers and specialty con-tractors, creating greater visibility within thedesign community and opportunities for in-creased sales.Jancy is a member of the CSI Chicago chapter

and is chairman of the chapter’s Industry RoundTable, which offers professional-developmentseminars for members. He conducts an annualclass about AIA-compliant programs for archi-tectural continuing education. He has written ar-ticles for a number of industry publications,including Concrete Decor, Landscape ContractorNational, Journal of Architectural Coatings, Con-struction Specifier, and Concrete Construction.Jancy has a bachelor of science degree from

the University of Illinois, is an ACI-certifiedConcrete Technician, and is certified by CSI asa Construction Documents Technologist (CDT).He was a founding board member of the Dec-orative Concrete Council and has been an af-filiate member of the National Ready MixConcrete Association (NRMCA), the AmericanSociety of Landscape Architects (ASLA), Amer-ican Institute of Architects (AIA), and the Amer-ican Concrete Institute (ACI).The author would like to acknowledge Jim

Cuviello, chairman of the Concrete PolishingAssociation of America’s (CPAA) PolishedConcrete Maintenance Committee, which isdeveloping guidelines for the maintenance andrestoration of polished concrete floors. D+D

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Editor’s Note: This article appeared inD+D in November 2013.

By Brad Burns, Concrete Polishing Association of America

Defining the UndefinableBuilding a system that gets predictable results is the challenge for the growing, but un-standardized concrete-floor polishing industry

Many architectural firms refuse to specify

polished concrete as a finished floor. They’re

often uncertain of exactly what contractors can

provide.

On the other hand, the sudden growth and

popularity of polished concrete, along with ad-

vances in equipment and diamond-tooling

technology, has spurred many contractors to

develop faster, more economical means for

processing concrete surfaces. They’ve created

many procedures for polishing floors to shiny

finishes.

The problem is that floors with “shiny fin-

ishes” are not always uniform in appearance

or performance. With the variations in

processes and concrete, it’s no wonder pre-

dicting the outcome of projects is difficult.

Another problem is that some contractors

This gleaming bonded abrasive polished concrete floor in a bank in Chester, Ill., showswhy, despite challenges, the polished concrete flooring industry still grows. The floor isan example of CPAA’s level 4 finished gloss. Photo courtesy of L.M. Scofield Co.

S ince the gloss and gleam of polished concrete began to grow in popularityabout 13 years ago, architects, designers

and contractors have struggled to specify andachieve predictable, uniform outcomes on projects.

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are almost superstitious when it comes tochoosing procedures, equipment or particulardiamond tooling. When these fail, contractorsoften hit panic mode in searching for solutions.When a sales technician offers the “perfect

solution,” which in fact does solve the immedi-ate issue, the contractor adopts this new prod-uct or process as the latest, greatest and best,to be used on all projects.The contractor doesn’t realize that due to the

many variations in concrete and on projects,this product or process will eventually fail aswell. Add an architect, designer or owner intothis mix, and it’s understandable why someprojects lead to discontent, frustration and un-fulfilled expectations.This repeatable and sometimes endless cycle

continues until the polishing technician learnshow and why some products and processeswork and others don’t.

Defining polished concreteTo help the contractor and the design team ef-fectively communicate about the processesused on projects, the Concrete Polishing Asso-ciation of America (CPAA) has defined “pol-ished concrete” and other common industry

terms. If architects, designers and contractorscan speak a common language in the specifi-cation process, then architects and designerscan more accurately explain what they want,and contractors can more consistently provideit.The CPAA defines “polished concrete” as

“the process of changing the concrete floorsurface, with or without aggregate exposure,to achieve a specified level of finished glossusing one of the listed classifications; BondedAbrasive Polished Concrete; Burnished Pol-ished Concrete; or Hybrid Polished Concrete.”Bonded Abrasive Polished Concrete —

Bonded Abrasive Polished Concrete is the mostcommon method for processing concrete.CPAA defines it as “the multi-step operation

of mechanically grinding, honing and polish-ing a concrete floor surface with bonded abra-sives to cut the concrete floor surface and torefine each cut to the maximum potential toachieve a specified level of finished gloss.”Most industry professionals are familiar with

this simple yet detailed process of workingthrough a series of diamond-tool grits to refinethe concrete and achieve a particular level ofgloss.Burnished Polished Concrete — Burnished

Polished Concrete became popular with “bigbox” retail project clients who wanted econom-ical installation without high gloss and clarity,and who were prepared for the recurring main-tenance cycles.CPAA defines Burnished Polished Concrete as

“the multi-step operation of mechanical friction-rubbing a concrete floor surface with or withoutwaxes or resins, to achieve a specified level offinished gloss.”This process starts with high-quality, engi-

neered concrete tightly monitored for quality-control during placement and finishing. It improves the concrete’s appearance and dura-bility with chemical hardeners, protective treat-ments and lightweight high-speed burnishers

The dark stripes on thisnewly poured 6,000-square-foot school addition bondedabrasive concrete floor resulted from an initial grindthat exposed aggregate unevenly. This type of problem is often caused bypoor communication betweendesign professional and polishing contractor, when aparticular grind is specified,rather than a specific aggregate exposure. Photocourtesy of Brad Burns,CPAA.

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fitted with diamond-impregnated buffing pads.Hybrid Polished Concrete — Hybrid Pol-

ished Concrete is simply the combination of thetwo other processes.It came about as contractors, always seek-

ing faster and better methods, adaptedbonded abrasive pads typically used forBonded Abrasive Polished Concrete to thelightweight, high-speed burnishers used forBurnished Polished Concrete.Using the more aggressive bonded abrasive

pads, instead of diamond-impregnated buff-ing pads, with lightweight high-speed bur-nishers on high-quality engineered slabsoffered terrific results. However, results variedaway from high-quality engineered slabs.Contractors found that depending on the

quality of the concrete, the method was limitedas to how well it could expose aggregate andachieve clarity.They overcame that limitation by using

heavy grinding and honing equipment fromthe Bonded Abrasive Polished Concreteprocess to create surfaces similar to the high-quality, engineered slabs that work so well forthe Burnished Polished Concrete method.

Using the larger, heavier equipment to es-tablish the specified level of aggregate expo-sure, contractors were able to process theconcrete to where they could switch to thelighter, faster Hybrid Polished Concrete equip-ment and complete projects quickly.This gave clients the glossy appearances

they wanted at lower installation costs.

Complications and variablesHowever, it also complicated matters by addingmany more variables to the polishing equation.Technicians who didn’t understand how andwhy couldn’t achieve consistent results.Polishing technicians unable to achieve what

the client wants often see the concrete surfaceas the problem. That’s not to say that concreteplacement and finishing doesn’t have a largeimpact on the outcome of a project, but it’s notalways an excuse for a polishing technician’slack of understanding or knowledge.That’s why the CPAA uses the “specified level

of finished gloss” system to assist design teamsand polishing contractors in beginning proj-ects with a clear understanding of what to ex-pect for final outcomes.

Here, a surface-coated concrete floor suffers from

exposure to the constructionprocess, degrading its

appearance. Communication and

coordination up front between the general

contractor and concreteflooring contractor can help

prevent such problems. Photo courtesy of Brad

Burns, CPAA.

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Measuring gloss and clarityThough important tools in measuring specifiedlevels of shine, the CPAA has found using glossmeters alone for quality control on polishingprojects to be unreliable.Applying stain-protection products or using

certain exposed aggregates in the concrete cannet short-term high-gloss readings without theadvantages of diamond tooling to refine the con-crete surface to a long-term high gloss.Gloss meters coupled with DOI (distinction

of image) meters offer better quality control forpolishing projects. DOI meters measure “clar-ity,” or the quality of the light reflected from theflooring surface. That’s often what clients seewhen they describe high gloss.

Finished Gloss LevelsFinished Gloss Levels are listed as 1-4, withvarying degrees of clarity and gloss.Level 1 has low clarity and gloss levels, with

a minimum of 20 on a DOI meter for clarityand 15 using a gloss meter. It’s often describedas a ground or matte finish.It still takes more than one pass with a dia-

mond tool to achieve Finished Gloss Level 1. Byproperly processing the concrete to meet theminimum level of 20 on the DOI meter, you offeryour client a better floor with a longer life cycle.This principle carries over to Levels 2, 3 and

4. Each level brings higher-quality clarity andgloss. When architects or designers specifyFinished Gloss Level 4, they set the standardfor very high-quality projects that require highlevels of attention to detail.For a Finished Gloss Level 4, polishing tech-

nicians must understand from the start that re-finement of each step is mandatory to meet thespecification.The CPAA is seeing immediate results from

the new terminology and specifications. We’vegotten many calls from architects, general con-tractors and polishing contractors about howthe new terminology or a clearly written spec-ification has helped define designs for suc-cessful projects.Concrete placement contractors have also

expressed approval of standardization of pol-ished concrete terminology. They’ve mentionedhow they are better equipped to understand

Re-grinding and polishing to aspecified class B/C salt andpepper exposure and level 3finish resolved the problemson the school addition floor(page 35), once the new polishing contractor and thedesign professional communicated using a common terminology and accepted standards. Photo courtesy of BradBurns, CPAA.

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what is required of them to attain a successfulpolishing project.The CPAA is still researching specific levels

of refinement to fully define Finished Gloss lev-els. Until then, we must rely on polishing tech-nicians who have the knowledge of how andwhy to achieve consistent, uniform and speci-fied results.You can download a complete 03 3543

Bonded Abrasive Polished Concrete specifica-tion from the CPAA website at http://con-cretepolishingassociation.com.

About the authorBrad Burns is the execu-tive director for theConcrete Polishing As-sociation of America(CPAA). As one of thefounding members ofthe CPAA, Burns hasbeen instrumental in de-veloping standard procedures for the polish-ing industry. He has been in the flooringbusiness for more than 28 years, and recentlyowned and managed a flooring company spe-cializing in polished concrete with his wife,Terry. He is a member of ASCC and ACI. Burnsis active in several industry association com-mittees. He is an international speaker andteacher working diligently to train and educatecontractors to better understand processes andbecome more successful. D+D