wet walls-creating significant savings

Wet Walls: Creating Significant Savings Through a Simple Material Change

Photo #1: Temperature differential in computer server room located adjacent to this roomcaused mold on wall. There was no insulation between the walls.

James L. Wichman

Environmental Health & Safety

The University of Texas at Austin

February 17, 2017

TABLE OF CONTENTS

Section Page Number

Table of Contents 1

Executive Summary 2

Introduction 3

Characteristics of Water Leaks and Drywall 6

Health Concerns 7

Regulatory Considerations 7

Readily Available Alternative Products 8

Implementing the Best Solution 9

What Resources Are Needed 10

Conclusions 10

APPENDICES

Appendix A Comparative Standards from Other Colleges and Universities

Appendix B Wet Areas Requiring Additional Protection

Appendix C Water Damage and Mold

Appendix D The History of Gypsum Board

Page 1 Wet Walls: Creating Significant Savings Through a Simple Material Change

Executive Summary

The use of standard gypsum wallboard and gypsum green-board have been found to be ineffective in areas designated as “wet areas.” There are a variety of water-related events which have a direct relationship with mold growth.

Hidden water leaks are the most difficult for trained investigators to detect and ultimately cause significant and expensive damage to building components. These water leaks are also a major source of staff health-related indoor air quality (IAQ) issues.

There are readily available products on the market today that can help mitigate these identified issues. While these replacement material costs are higher than those currently in use, the cost will be mitigated by reduced staff-related IAQ issues and material remediation.


Wet Walls: Creating Significant Savings Througha Simple Material Change

Introduction:

The University of Texas at Austin has been using gypsum wallboard since the 1960’s. This material replaced plaster applications and significantly reduced cost of building construction. During the energy crisis of the 1970’s, new buildings and buildings being retrofitted were designed to be more energy efficient. This ushered in the era of “tight buildings.” Most of these buildings are tight, energy-efficient designs with outside air provided through recirculating air-conditioning systems. As advantageous as the design seemed to be originally, numerous hidden problems have surfaced over time.

The term "sick building syndrome" (SBS) is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. The occurrence of sick buildings became much more wide spread. The complaints may be localized in a particular room or zone, or may be widespread throughout the building. Occupant indoor air quality (IAQ) complaints have increased significantly due to increased awareness of this issue.

Environmental Health and Safety (EHS) employs mold consultants who regularly respond to water intrusion events that occur through: blocked drain lines, leaking water lines and steam piping, excess condensation from HVAC systems, activated fire sprinklers, improper landscaping, waterproofing failure, vandalism, and rain events.

Photo #2: Significantly warped machine shop wooden floorMop sink overflowed


This report is concerned only with those areas where water lines are installed for use in a specified space or elevated levels of moisture are a part of the working environment. These areas are commonly referred to as “wet areas.” The primary purpose of this report is to focus on those areas where a change in use of construction materials will have a significant and positive impact. This will reduce recurring health-based complaints from building occupants as well as reduce damage to infrastructure and associated departmental labor allocation.

Mold as the result of a water intrusion event is one of the most significant issues EHS and its staff of mold consultants encounter. Mold is known to impact and proliferate on wet gypsum wallboard after 48-hours of being wet which can cause significant inconvenience to students, faculty, and staff.

Photo #3: Mold behind a bookcaseWater source was from a water leak on the other side of the wall.

Gypsum wallboard has several significant advantages over other wall materials: ease of installation, fire resistance, sound isolation, durability, economy, and versatility. Gypsum wallboard is usually much less expensive to install than plaster. Gypsum wallboard is considered to be more stable than plaster, but not as durable. However, it is much easier to repair when it is damaged. Dents or holes can be quickly and easily repaired using drywall joint compound.


Photo #4: Mold on drywall in bathroom from window leaks

The University does not define “wet areas” for their Design and Construction Standards and continues to specify regular gypsum wallboard for applications in water prone areas. There have been limited occasions in the past when gypsum green-board was specified in some of these areas. Gypsum green-board is a moisture resistant drywall that was designed in the 1960’s and is water resistant but not water repellent. Experience has shown that this material is ineffective in wet areas.


Characteristics of Water Leaks and Drywall:

A leaking water pipe hidden from view behind a wall impacts not just the immediate area but also areas down-gradient from the leak. In addition, the leak may be located behind casework increasing the difficulty of detection. Slow persistent leaks are the most difficult to detect that ultimately cause significant damage to the building infrastructure. Interdepartmental cooperation and labor allocation are also significant to achieve the repairs after discovering the damage.

Phot #5: Mold behind laboratory cabinetryMultiple water leaks from water lines,

condensation lines, and sanitary drains

Groups typically involved in locating and applying corrective actions for a water intrusion event include:

• EHS mold consultants;

• The college or department responsible for the area where the leak occurs;

• Building managers;

• Facilities Services

• Zone shops;

• Custodial Services

• Project Management and Construction Services;

• Carpenter Shop;

• General Construction Shop; and

• Third party contractors.


Health Concerns:

Typical reported symptoms include: headache; dizziness; nausea; eye, nose or throat irritation; dry cough; dry or itchy skin; difficulty in concentration; fatigue; sensitivity to odors; hoarseness of voice; allergies; cold- or flu-like symptoms; increased incidence of asthma attacks; skin irritation; and personality changes. Excessive work stress or dissatisfaction, poor interpersonal relationships, and poor communication are often seen to be associated with SBS. Recent studies show that a combination of environmental sensitivity and stress can greatly contribute to SBS.

The cause of the symptoms are usually not known. Reduced work efficiency and increased absenteeism are common. Most of the occupants report relief soon after leaving the building, although lingering effects of neurotoxins may occur.

There was a time that any staff reporting issues were dismissed as hypochondriacs and neurotics, but investigators and regulators have acknowledged that the modern office environment can be toxic when not properly maintained. Moving to a different office or different building usually resolves the original issue, however, it is a short term solution.

Regulatory Considerations:

EHS Mold Consultants are all licensed by the Texas Department of State Health Services (DSHS) to assess damage, discover causation, design remediation protocols, and determine if all remediation actions have been properly enacted so that the project can proceed to reconstruction. EHS Mold Consultants use federal, state, and national standards organizations; and University IAQ rules, protocols, and guidance in order to make informed decisions. In addition, EHS-licensed asbestos personnel working in conjunction with other departments are responsible for determining if the impacted area has asbestos or lead-paint which would have a direct impact as to who is qualified to perform work. Finding asbestos and/or lead paint in the impacted area requires specific modifications of procedures and protocols which are conveyed to other departments.


EHS mold consultants assess each reported water intrusion event to determine the best course of action for that specific event. Actions may include any or all of the following: drying with fans, additional drying using dehumidifiers, removal of vinyl or rubber cove base with drilling of ventilation holes to assist drying, removal of wetted gypsum wallboard, removal of wetted casework, and disposal of all wetted cellulose materials. EHS designs remediation protocols and monitors all project response actions from initial reporting to reconstruction.

Photo #6: Mold on gypsum wallboard of reported non-impacted room

Readily Available Alternative Products:

There are two major categories of non-paper faced wallboard: cementitious and fiberglass-mat. There are two alternatives between the two major categories of non-paper faced wallboard.


Cementitious Wallboard: cement board and fiber-cement board.

Cement board contains a cement core and glass mats on both sides to strengthen the board. These boards are relatively heavy and difficult to cut, but they are very durable, dimensionally stable, and have a great bonding surface. While it is water resistant, it is not waterproof.

Cementitious wallboard is installed similar to regular gypsum wallboard and it is typically used as an underlayment (backer-board) for many interior applications, such as kitchen countertops and backsplash applications, bathroom shower and tub enclosures, whirlpool tubs, sub-grade walls, drinking fountain or plumbing alcoves, and walls for bathrooms. It’s resistance to mold allows it to be used in areas where a vinyl wall covering is desired for an architectural finish where regular gypsum wallboard applications are inappropriate.

Disadvantages of cementitious wallboard use include: many drywall installers are inexperienced with interior application installations; it is less forgiving regarding installer mistakes and it is more expensive than regular gypsum wallboard. Much more rigorous safety precautions must also be taken when cutting cementitious wallboard. Workers need to wear respiratory protection and increased ventilation is required at the cutting surface even if cutting outdoors. Rotary power tools need to have an operational vacuum attached.

Fiber cement backer-boards have reinforcement throughout the core but contain no differential facings. The fiber is wood rather than glass. These backer-boards are less expensive than other backer-boards and are relatively easy to cut. They are produced only at maximum 1/2” dimensional thickness and while moisture-resistant, they are not waterproof.

Fiberglass-Mat: coated glass mat and fiber-reinforced gypsum board.

Coated glass mat boards typically have a gypsum core with glass fibers sandwiched between fiberglass surface mats. It is much lighter and easier to cut than cementitious boards. It will soften when water seeps through the joints or gets behind the waterproof surface. Fiberglass mats irritate bare skin.

Fiber-reinforced gypsum boards while moisture-resistant are only appropriate for areas experiencing infrequent wet conditions. While these are great non-paper-faced backer boards, they are NOT recommended for truly wet areas like a tub or bath and should only be used where wetting potential is minimal, such as a kitchen or laundry room.


A distinct disadvantage to the use of fiber-reinforced gypsum boards is that once the gypsum core has been wetted it begins the process of delaminating; the core matrix is no longer intact, which shortens its usefulness long term. An additional water intrusion event in the same location can render the wallboard inadequate to the point where the wetted material must be replaced. A concern with fiberglass-mat wallboard is the rougher surface of the panel as compared to regular drywall, therefore it requires skim coat of joint compound to achieve a smooth finish.

Fiberglass Reinforced Plastic (FRP): This is the only material that is waterproof and is typically specified for kitchens and vivarium’s. However, FRP must be applied over a water resistant backer-board.

Implementing the Best Solution:

Multiple steps are required to implement changes in operational practices that will help to eliminate some of these issues.

1. Commitment by University entities who specify materials for construction projects or who contract with those who specify materials for University structures.

2. Senior management needs to be supportive of the new methodology.

3. Education and training of Architects and Project Managers as to the reasoning behind the change in methodology is a crucial step.

4. Office of Facilities Planning and Construction (OFPC) design criteria need to be altered to reflect changes in procedure.

5. Project Management and Construction Services (PMCS) design criteria need to be altered to reflect changes in procedure.

What resources are needed?

Beyond materials, there are no additional resources required.

These recommended materials are to be used for new construction and renovation only. Retrofitting of wet areas is not required. Gypsum wallboard and ‘green-board’ are not to be used in areas designated as wet areas.

Conclusions

Hidden water leaks are the most difficult for trained investigators to detect and ultimately cause significant and expensive damage to building components. These water leaks are also a major source of staff health-related indoor air quality (IAQ) issues.

There are readily available products on the market today that can help mitigate these identified issues. While these replacement material costs are higher than those currently in use, the cost will be mitigated by reduced staff-related IAQ issues and material remediation.

No additional resources are needed to enact these changes materials are to be used for new construction and renovation only. Retrofitting of any identified wet areas is not required.


APPENDIX A


Comparative Standards from Other Colleges and Universities: Texas A&M University - Facility Design Guidelines: All interior gypsum wallboard

should be at least a DensArmor® or DensArmor Plus® or equal mold resistant wallboard.

University of Colorado - Construction Requirements: Use moisture and mold resistant backer board at all wet walls of bathrooms and walls perpendicular to that wall; height to meet International Building Code (IBC) code requirement.

The University of Houston - Campus Design Guidelines and Standards: wet walls are required to be cement board. Where abuse of wall surfaces is anticipated gypsum board walls will be composite cement board or glass fiber reinforced gypsum.

Sam Houston State University - Design & Construction Standards: Wet areas and/or tile backer board: Use cement backer board for tile. (Required for shower stall or tub surround applications.) Avoid paper-faced moisture resistant gypsum board panels (“green-board”).

Eastern Michigan University – Construction Standards: Use of “green-board” is prohibited. Cement board or equivalent product shall be used as backer-boards at wet locations (e.g. showers).

University of Wyoming - Construction Standards: If a gypsum board product is used as backing, it shall be a fiberglass-mat product and include a weather barrier to resist the effects of moisture. Ceramic wall tiles should only be used on walls of masonry construction or on stud walls with cement backer board.

Auburn University - Design and Construction Standards: Fiberglass-mat wallboard and ceramic or other hard tile full height on wet walls. For Kitchens, Food service Venues and Break Rooms – Fiberglass-mat wallboard and porcelain or quarry tile or epoxy paint on concrete masonry unit (CMU). Painted gypsum wallboard is unacceptable.

Indiana University - Building Design Standards: Use moisture and mold resistant gypsum wallboard at restrooms and all areas located below grade level.

University of Iowa - Design Standards and Procedures: Mold resistant drywall shall be used in intermittently wet areas (restrooms, wash rooms, custodial closets, etc.).

Princeton University - Facilities Department Design Standards Manual: In bathrooms materials must be water-resistant; at a minimum, use water-resistant


gypsum board for walls and ceilings. At tiled walls, backer materials to have a glass mat facing with a moisture resistance gypsum core at a minimum. In any “wet” laboratory the preference is for mold resistant gypsum wall board.

University of Arizona - Manual of Design and Specification Standards: Wet areas: Specify moisture resistant board as a tile backer in toilet/sink areas with limited water exposure. (Products such as National Gypsum eXP® Gypsum Board, or similar).

Arizona State University - Project Guidelines: All Gypsum Board in all areas of toilet rooms and other areas where moisture will be present in any form will be mold resistant.

MIT - Department of Facilities Building System Design Handbook: Drywall assemblies should not be used in wet areas such as animal rooms, cage wash rooms, large shower rooms, and other wet areas.

University System of Georgia - Baseline Design Standards for Student Housing: Wet area walls to be ceramic tile or other water resistant material over cement backer board.


APPENDIX B


WET AREAS REQUIRING ADDITIONAL PROTECTION

Usage Areas Cement Board

Fiber-Cement Board

Coated Glass- Mat

Fiber-Reinforced

Gypsum BoardNOTES

Autoclave Room

Bathroom Behind commodes, urinals, sinks

Breakroom Behind cabinetry, fridge, stove

Cold Room Insulation between walls and backerboard on all abutting walls of cold room

Fish Lab

Janitorial Closet

Kitchen Backerboard is required because seams are not impervious

Laundry Room Walls and ceiling required

Mop Sink Behind sink and 2’-4’ on each side

Plumbing Chase

Sauna Walls and ceiling required

Shower Walls and ceiling required

Sub-Grade Wall

Swimming Pool

Vivarium

Water Fountain Back-splash Behind fountain and 2’-4’ on each

side

Wet Lab

Whirlpool This table is to be used for new construction and renovation only. Retrofitting of wet areas is not required. Gypsum wallboard and ‘green board’ are not to be used in the areas listed in this table. The dot indicates the building material is acceptable for that location.

Computer server rooms that share common walls with a temperature differential in the rooms greater than 5⁰F will require insulation between walls and Cement Board or Fiber-Cement Board on all abutting walls of the server room.


APPENDIX C


Water Damage and MoldDrywall is highly vulnerable to moisture due to the inherent properties of the materials that comprise it: gypsum, paper, and organic additives and binders. Gypsum will soften with exposure to moisture, and eventually turn to a mushy paste with prolonged saturation, such as during a flood. During such incidents, some or all of the drywall in an entire building may need to be removed and replaced. Furthermore, the paper facings and organic additives mixed with the gypsum core are food that mold uses to proliferate. The porosity of the board—introduced during manufacturing to reduce the weight of the board, lowering construction time and transportation costs—enables water to rapidly reach the core through capillary action, where mold can grow inside. This capillary action can result in water spilled at the base of a wall being wicked upwards and damaging the material up to several inches off the ground.

Finally, drywall's paper facings are edible to termites, which can eat the paper if they are infesting a wall cavity that is covered with drywall. This causes the painted surface to crumble to the touch, its paper backing material having been eaten. In addition to the necessity of patching the damaged surface and repainting, if enough of the paper has been eaten, the gypsum core can easily crack or crumble without it and the drywall must be removed and replaced.

Water that enters a room from overhead may cause ceiling drywall tape to separate from the ceiling as a result of the grooves immediately behind the tape where the drywall pieces meet become saturated. The drywall may also soften around the screws holding the drywall in place and with the aid of gravity, the weight of the water may cause the drywall to sag and eventually collapse, requiring replacement.

In many circumstances, especially when the drywall has been exposed to water or moisture for less than 48 hours, professional restoration experts familiar with structural drying methodologies can introduce rapid drying techniques. These techniques are designed to eliminate elements required to support microbial activity while also restoring most or all of the drywall. This aids in avoiding the cost, inconvenience, and difficulty of removing and replacing the affected drywall.

It is for these reasons that cement board is used for rooms expected to have high humidity, primarily kitchens, bathrooms, and laundry rooms.


APPENDIX D


The History of Gypsum BoardThe predecessor of today’s gypsum board was called “Sackett Board,” a composite material made of layers of thin plaster placed between four plies of wool felt paper. The manufacturing process was patented in 1894 by Augustine Sackett, now considered the grandfather of the gypsum board manufacturing industry.

A sheet of Sackett Board was approximately 1/4 inch thick and 36-inches square. Its open edges tended to erode and the felt paper did not provide for a satisfactory wall finish. However, it was an excellent base for the application of gypsum plaster and in many geographic areas, Sackett Board became a replacement for wooden slat lath.

A rapid series of improvements in board manufacturing technology between 1910 and 1930 resulted in the finishable material that gypsum board is today. In 1910, a process for wrapping the board edges was created, followed in short succession by the elimination of the two inner layers of felt paper, the replacement of the exterior facings with paper-based coverings, the creation of air-entrainment technology to make board lighter and less brittle, and the evolution of joint treatment materials and systems.

In the 1940s, manufacturers sought to increase the naturally occurring fire resistance of regular core gypsum board. A new product was eventually introduced that clearly demonstrated “eXtra” fire resistance, hence the name “type X.” Gypsum, glass fibers, and vermiculite are the components of type ‘X’ that provide superior fire resistance.

Further modifications to the original type ‘X’ were made in the 1960s. The formulations of gypsum board used in some systems particularly ceiling systems, were improved without compromising the fire-resistive qualities. The new product demonstrated additional fire resistance over type ‘X’ core, and thus the term “improved type X” was coined.

To meet market demand in the United States and Canada, each year over 20 billion square feet of gypsum board is manufactured.


wet walls-creating significant savings

Documents