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Breaking Old Rulesfor Air Barrier Installation

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Breaking Old Rules for Air Barrier Installation

VaproShield USA. VaproShield Canada915 26th Ave. N.W., Suite C5 101-1001 West Broadway, Suite 545Gig Harbor, WA 98335 Vancouver, BC V6H 4E4Fax: 253-858-3297 Toll-Free: 1-866-731-7663 Fax: 866-340-2587 Toll Free: 866-871-8263

As buildings and what we demand of them have evolved, so has the technology for providing air, vapor, and water controls for the building envelope. This course will provide an overview of a sophisticated air barrier system using a self-adhered membrane that is not only highly effective, but also simple to apply with a minimum of surface preparation, and can be applied during cold or rainy conditions.

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Purpose and Learning Objectives

Purpose: As buildings and what we demand of them have evolved, so has the technology for providing air, vapor, and water controls for the building envelope. This course will provide an overview of a sophisticated air barrier system using a self-adhered membrane that is not only highly effective, but also simple to apply with a minimum of surface preparation, and can be applied during cold or rainy conditions.

Learning Objectives:

At the end of this program, participants will be able to:

• explain the natural movement of air, heat, and vapor into and out of a building, and how that relates to energy savings, occupant health, and durability

• discuss the history of building paper and water-resistive barriers (WRBs)• identify the performance and testing characteristics of breathable, self-adhering WRBs and air barriers (AB) that

contribute to a durable and energy-saving building• describe the different types of air barrier technology for a durable building envelope, and• examine several case studies where an innovative vapor-barrier system sped up construction, lowered costs, increased

building envelope quality, and contributed to green building certification.






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Table of Contents

Introduction 7

Building Science: The Movement of Air, Heat, and Vapor 9

History of Building Paper, Water-Resistive Barriers (WRB), and Air Barriers 25

Performance and Testing 36

Specifications and Installation 42

Green Credentials 51

Summary and Resources 55

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Introduction






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Introduction

In the beginning, humans were hot or cold, wet or dry, comfortable or miserable, all depending on the weather. As we evolved, comfort became a priority, and then energy savings, and eventually health, durability, and sustainability rose up inour collective concerns. Building paper and water-resistive barriers (WRBs) emerged and then evolved to meet our new needs and expectations. Today, the architect or specifier can choose from an astonishing array of water-resistive/air barriers with various capacities and installation strategies, from those that are tacked, fastened on, glued on, or sprayed on, and, ultimately, those membranes that self-adhere.

To clarify the difference between water-resistive/air barrier choices, this course is about self-adhered, vapor-permeable WRBs/air barriers, and the role they can play in the design and construction of superior buildings that satisfy owners, serve the needs of occupants, and help shield the architect/owners and general contractors from risk. We start with the basics of heat and energy flow, then review the history of air barriers, discuss the basics of self-adhered products and their installation benefits. Throughout the course, we will look at some case studies where a self-adhered WRB/air barrier was used to further the goals of designing and creating a superior building.

Let’s begin with a review of basic building science.






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Building Science: The Movement of Air, Heat, and Vapor






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In the design and construction of buildings, it’s important to understand how air, heat, and vapor move in and out of tight structures.

The way air, heat, vapor, and liquid water move in and out of a building is best defined by the second law of thermodynamics. This is the study of heat and energy and how they move or transfer.

Air, heat, vapor, and liquid water—driven by the immutable laws of nature—move from more to less when given a chance; this means that higher concentrations move to lower concentrations. Hot moves to cold. Wet moves to dry. Higher pressure moves to lower pressure.

When the designer and contractor understand how air, heat, and vapor move in and out of buildings, there is a better chance that the structure will be durable, healthy, and energy efficient.Image courtesy of Green Building Advisor Scott Gibson (August. 17, 2010).






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This is easily understood during a northern winter. The cold air outside seems to want to come inside, but it’s really the warmth that wants to leave the house. Left uncontrolled, this will occur until the temperature is the same inside and outside.

Insulation and air barriers keep the warm air from escaping in heating climates, predominantly northern states, and keeps the hot air outside in cooling climates, predominantly in southern states.






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Air Barrier

For insulation to be effective, we need an air barrier to control convective heat transfer. An air barrier is required whether the insulation performs that function or not.

This will ensure that connections between the insulation materials, as well as penetrations (windows, doors) and transitions from wall-to-wall, wall-to-roof, and wall-to-foundation, are properly sealed.






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Air Barrier

This calls for an air barrier to be installed in the building envelope. In situations where the air pressure is not equal inside and outside (stack effect, wind, or mechanically induced pressure difference), and there is no identified air barrier, the air will move from high to low pressures.






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Vapor Controls

This brings us to the issue of vapor, or water in a gas form. We feel most comfortable when the interior relative humidity ranges from 40% to 60%. In a hot and humid climate, it needs to be below 50% to manage some indoor air-quality issues. In the southern states in summer, however, the outside relative humidity is often more than 90%.

We use the air-conditioning to lower the temperature and the relative amount of moisture in the air in the form of vapor. The vapor movement from higher to lower concentrations through building materials is typically minor, and slow enough to not necessitate additional vapor control beyond the natural vapor control of the materials used in wall construction.

It is primarily the air-transported moisture that moves through the building’s envelope that is a problem.

When surfaces reach dew point, the vapor in the air, or from vapor diffusion, condenses, changing into liquid water. If this water is trapped in a wall, floor, or roof cavity and is not allowed to dry, it can, over time, cause problems. It not only degrades the building materials, resulting in a food source for fungus, it also causes oxidations that will rust metal studs,and other metallic wall components.






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Vapor Controls

Ideally, a building envelope membrane is resistant to liquid water and air, but allows vapor to enter and exit, within certain bounds. Vapor movement is the rate at which water vapor can diffuse through a material, known as its water vapor transmission rate (WVTR) or water vapor permeance.

The permeance is measured in perms, where one perm is one grain of water per hour through 1 sq ft of material, induced by a vapor pressure difference of 1″ of mercury across the two surfaces of the material. Its driving force is a difference invapor pressure, and its movement is always high to low. A high vapor pressure means that the number of water vapor molecules in the air is high. Vapor diffusion is different than air transport or convective vapor transport as vapor diffusion is typically very slow.






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The Stack Effect

In heating climates—areas where there is a significant need for heating—you may have noticed how the upstairs is often warmer than the downstairs if the ventilation is not balanced.

Alternately, it is warmer at the ceiling than at the floor. As the warm air rises, it creates a positive pressure at the top of the building and a negative pressure below. These pressure differences force warm air out through the top of the building, sucking cooler air into the lower section of the building. This is called the stack effect.

The stack effect and air leakage adds to the amount of air the HVAC system needs to cool or heat, and will also bring in outside pollutants and moisture.

The stack effect brings in outside moisture and pollutants, which adds to the work of the HVAC system.






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Case Study: Banks Phase II

The performance potential of a self-adhered membrane was demonstrated recently in the Banks Phase II project in Cincinnati, Ohio, where the designers changed from a fluid-applied air barrier to a self-adhered, water-resistive, air barrier sheet membrane.

Located between Paul Brown Stadium and Great American Ballpark in downtown Cincinnati, the Banks project is a multi-stage development featuring retail, office space, hotel rooms, and residential space. The second of three phases is a 291 apartment mixed-use building that also features 20,000 sq ft retail space.






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The senior estimator at the time, Josh Turner, explains why his company switched from fluid-applied to self-adhered barrier, “The major reasons we switched to the sheet-applied were, number one, the temperature at which we were going to begin installing the air barrier membrane was going to be too cold for fluid-applied.”

Turner continues, “and the other thing was that the building was going together in sections, floor-by-floor; and to have a crew to come in and do the fluid-applied would have been 12 to 15 mobilizations on the project. So what we sold the contractor on was that we could do a product that we could install on smaller sections at a time that would be easier without having all the equipment to set up, and that way we could progress as the building went up.”






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Turner added that the self-adhered membrane was also better than fluid-applied because of the wind factor. “In downtown, there is quite a bit of wind,” he notes, “and that was the other thing we were worried about with fluid-applied was overspray on the windows below.” In some parts of the project, the finished portion was below the point where the membrane would be installed. The cost and trouble of masking off the floor below to protect it from the spray above would have been prohibitive.

Shims used under horizontal cladding attachment components to create a ¼″ rainscreen cavity, allowing for unimpeded vertical drainage of moisture away from the building envelope.






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Case Study: Eleven55 Ripley

More than 60,000 sq ft of self-adhering, water-resistive, vapor-permeable air barrier sheet membrane was applied to the Eleven55 Ripley apartment complex in Silver Springs, Maryland, as an in-process replacement for a failing fluid-applied air barrier that was unable to withstand the area’s cold temperatures and rainy weather.






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Case Study: Eleven55 Ripley

After a particularly windy night during construction, the installation crew arrived to find the original air barrier torn and damaged. The team decided to replace the failing fluid-applied barrier with a self-adhered WRB/air barrier, which requires no primers and has the added flexibility of being installed in temperatures as low as 20°F.






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The Solution

To be most effective, the thermal (insulation) barrier, air barrier, and moisture barrier (liquid and vapor water) should be continuous all around the building exterior, including all rough openings such as windows.

“The key,” says building science consultant Scott Wood, “is to control air flow (which brings in the vapor), and stop convective heat flow.”

Stopping airflow and liquid water from entering a building envelope, yet allowing vapor to come and go, are the sophisticated functions demanded of today’s modern building envelopes.

“The key to a efficient, healthy, and durable building is to control airflow, which brings in vapor, and stop heat flow.”






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Case Study: Federal Center South Building

Approximately 40,000 sq ft of self-adhered, water-resistive, vapor-permeable air barrier membrane was used on the reconstruction of the Federal Center South Building 1202 in Seattle, Washington. The 209,000 sq ft building serves as the regional headquarters for the U.S. Army Corps of Engineers (USACE) Northwest District. The self-adhered WRB/air barrier membrane helped the reconstruction project achieve a level of energy efficiency at the top 1% of all U.S. buildings, functioning as a continuous air barrier membrane system, while protecting the structure from the damaging effects of moisture.

Despite a slim $65 million budget, Building 1202 “achieved the most innovative and high performance design in federal government building projects,” according to the American Institute of Architects.

“Federal Center South Building 1202.” The American Institute of Architects. American Institute of Architects, 2016. Web. Accessed May 2016






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Case Study: Federal Center South Building

Awarded one of AIA’s Top 10 Green Projects 2013 and a National Design-Build Award from Design-Build Institute of America, Building 1202 utilized a host of energy-saving and sustainable products to achieve a high performance, long-lasting structure.

The design-build team has 0.5% of the original contract value at risk, pending verification of the building’s energy performance after one year of occupancy. This risk is shared between Sellen Construction, ZGF Architects, and the major subcontractors and design consultants who have primary responsibility for Building 1202’s energy performance. Photo courtesy of Benjamin Benschneider






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History of Building Paper, Water-Resistive Barriers (WRB), and Air Barriers






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While the art and science of elegant, affordable, manageable control of air and heat in buildings is now commonplace and required by codes and standards, it wasn’t always like that.

Homes in the early part of the 1900s were drafty, with lap siding and empty stud bays, and were alternately cold or hot, dry or humid, depending on the season and location. The status quo worked for several reasons—we had not yet invented air-conditioning, so we didn’t know that sleeping on the porch in summer was not the only option.

We were accustomed to feeling the impact of seasons and weather, even inside the house. The leakiness of the house let heated air escape in winter, which was uncomfortable and costly, but it also ventilated the house, which provided benefits in drying the walls and cleaner indoor air, depending, of course, on the quality of the incoming outdoor air.

When a brewery was founded in St. Paul, Minnesota, in the mid 1800s, little thought was given to air or vapor intrusion. However, when the brewery was converted to artists’ lofts in 2013, the buildings were brought up to today’s standards with a technologically advanced self-adhered WRB/air barrier.






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In time, builders tacked simple kraft paper onto the studs before adding the cladding to stop liquid water entry into the building. The paper could get wet and then dry out, which lessened the chance of mold and rot. Over time though, season after season, the paper tended to degrade, and that’s when pine tar was added to make the paper more resistant to moisture.

Insulation was not a concern in the early part of the 1900s. Homes were generally heated with wood or coal fired furnaces and steam heat, and in cold northern winters, you simply added more wood or coal if you were cold, or opened the windows if you were hot.

The use of tar paper, now saturated with petroleum-based products instead of pine tar, was a very popular way to build back in the middle of the last century as the paper achieved its main goal—to control water. However, it was difficult to use in cold weather, as the corners had a propensity to break. Eventually, the product was improved to make it a little more durable.

The invention of air-conditioning raised expectations of occupant comfort. Once we experienced the comfort of a cool home during a hot summer, there was no going back.






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Case Study: Hyatt Place Chicago-South/University Medical Center

Hyatt Place Chicago-South/University Medical Center, with its unique blade-shaped design, zinc shingle, and porcelain tile facade, serves as the appealing gateway to Hyde Park’s flourishing Harper Court commercial district.

Accommodating the Hyde Park/Kenwood community, and the adjacent University of Chicago campus and Medical Center, the 131-room hotel is the first new hotel to be built in 50 years in this historic neighborhood.






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Case Study: Hyatt Place Chicago-South/University Medical Center

More than 54,600 sq ft of self-adhered, water-resistive, vapor-permeable air barrier membrane contributed to the sustainable, energy efficient envelope of the LEED-NC Silver Certified hotel. The membrane helps reduce high energy costs that typically occur due to air leakage. It also allows damp sheathings to dry quickly and moisture vapor to escape, ensuring good indoor air quality while reducing incidence of mold, mildew, lumber distortion, and metal corrosion.

The building envelope system also fits into Harper Court’s LEED for Neighborhood Development (ND) Gold certification, which makes it the highest LEED rated project of its kind in Illinois and among the top in the United States. Designed by Legat Architects, Hyatt Place Chicago-South/University Medical Center has earned several awards, including: the 2013 CISCO Project of the Year, the 2014 Building Design + Construction Building Team Award, a Lake County Contractors Association Honorable Mention, and a ranking by Trip Advisor as one of Chicago’s greenest hotels.






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In the mid 1970s, the oil embargo and energy crisis forever changed how we build, insulate, and ventilate homes. However, the correct changes didn’t come right away. and there were many building and material failures while building scientists, building material manufacturers, builders themselves, and code and standards determined how to “build tight, ventilate right,” as we often hear today.

Once energy became more expensive, insulation got thicker, and trapped vapor became a major, expensive, and destructive issue.

In the 1970s, modern house wraps came on the market and revolutionized air and moisture barriers. Yet, the same challenges remained: the material would easily rip and tear, both from improper installation using staples and from the forces of wind. Once the integrity of an air barrier is compromised, its value as a protective factor diminishes.






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Peel-and-Stick Membranes

Peel-and-stick membranes with a primer application eventually came on the market. These membranes promised a more thorough attachment as they did not have the staples or other devices that caused tearing.

However, this type of membrane requires a primer to be applied to the sheathing before the membrane is applied. Any benefits that were gained with the promise of a more thorough attachment were lost as the primers contained toxic VOCs.

The use of toxic primers were not only harmful for the environment, but also diminished the water vapor permeance of the membrane. Additionally, joint and corner treatments were often needed and the installation became time and weather sensitive.






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Fluid-Applied Air Barriers

Fluid-applied air barriers have gained attention in the design and build industry as the application of this type of membrane is smooth and consistent. Despite the smooth application, there are some issues and drawbacks with this type of product:• Rain will wash off the material if it’s not fully cured. • Low temperatures restrict curing. • Transition membranes need to be included to span gaps.• Lengthy prep time is needed for the substrate.• Personal protective equipment is required as the chemical liquid is potentially harmful to installers and by-standers.• Methods must be put into place to contain spills and overspray. • Surface preparation can be arduous due to the need to fill holes and gaps before application.• Product can potentially become contaminated with common construction debris and dust.






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Case Study: Long Beach High School

In mid-October 2012, before any cladding had been applied to this $16.5 million project, Superstorm Sandy hit Long Island, New York. At that time, approximately 50,000 sq ft of self-adhered WRB/air barrier membrane enveloped the three story, 20,000 sq ft addition to Long Beach High School.

From the time the self-adhered WRB/air barrier was installed on this high school to the time the cladding could be installed, Superstorm Sandy devastated the area. But the WRB/air barrier remained intact.

Photo courtesy of Concrete Engineering International Volume 17, Number 4, June 2013

Installed over a lateral force resisting system that included only concrete walls, precast concrete planks, and masonry shear walls, the self-adhered WRB/air barrier membrane served as the school’s only protection during the storm.

Enduring days of wind gusts reaching more than 70 mph and consistent, torrential rainfall, the water-resistive, vapor-permeable air barrier membrane remained entirely intact.






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Case Study: Long Beach High School

A year after the storm, in October 2013, the addition, which has been occupied by students and staff since early 2012, was still without cladding and protected only by the membrane; it was safe enough for habitation and showed no signs of leaks within the building envelope.

Long Island after Hurricane SandyPhoto courtesy of Publicnewsserivce.org






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Self-Adhered, Water-Resistive, Vapor-Permeable, Air Barrier Sheet Membrane

Finally, we come to self-adhered, water-resistive, vapor-permeable air barrier sheet membranes. They combine the performance necessary to reduce risk and to create superior buildings with the ease of installation, which lessens the chance it will suffer from installer error or hold up a job due to weather or sequencing. These types of membranes do not require a primer and are applied directly to the sheathing. Application can take place in a variety of weather conditions as well.

Self-adhered, water-resistive, vapor-permeable air barrier sheet membranes that do not require primer are applied directly to the sheathing in a wide variety of weather conditions.

Self-adhered field membrane shingled over head flashing

Apply hybrid liquid applied flashing inside rough opening + 1″ on face

Pre-cut (11 ¾″ or 19 ⅔″ W) flashing self-adhered membrane applied directly to sheathing folded inside of rough opening






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Performance and Testing






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Performance of Breathable, Self-Adhering, WRB/Air Barriers

In the design and build industry, this new class of breathable, self-adhering, water-resistive barriers/air barriers is getting attention. The industry has specifically recognized the product’s extra UV protection used in open joint applications.

Industry experts listed the product’s attributes as: a black, UV-stable, water-resistive, and vapor-permeable air barrier membrane for open-joint rain-screen cladding. Additionally, the zero-VOC membrane can be installed in a single layer in temperatures as low as 20°F.

The Class A fire-rated material has a Flame Spread Index of 0 and is highly vapor-permeable, which reduces the incidence of mold, mildew, and rot.






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Testing Method ASTM E2357

The guaranteed efficacy of these products depends on reliable testing methods. The ASTM E2357 “Standard Test Method for Determining Air Leakage of Air Barrier Assemblies” measures the performance of an assembled system rather than the amount of air leakage through a single component. The installed assembly is tested under a multitude of negative and positive air pressures, including extreme wind gust load conditions.

The ASTM E2357 test method measures and compares the air leakage through an opaque, non-penetrated wall assembly against the air leakage through a wall assembly with pipe penetrations, brick ties, electrical boxes, foundation transitions, and lap seams and flashings. The walls are subjected to extreme positive and negative wind load conditions and the measured air leakage recorded. If the measured air leakage rate passing through the wall with penetrations is greater than 10% of the opaque wall, the assembly fails. A passing grade for this test indicates the quality of the system to ensure the installation as provided will be airtight.






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ASTM E2357 Differs From Previous Test Standards

It’s important to note that while codes regulate air-leakage rates or limits, test methods verify the performance characteristics. The more common requirement for acceptable air permeance rate for a membrane is set at 0.004 cfm/ft2at 1.57 psi of air pressure (0.02 L/s m2 at 75 Pa).

One such test method used is ASTM E2178 “Standard Test Method for Air Permeance of Building Materials.” In addition to flexibility, tensile strength, and a few other durability tests, it measures the air permeance of just the individual air barrier materials.

With the introduction of ASTM E2357, it is realized that most building projects experience significantly higher wind loads, both negative and positive than 1.57 psi (75 Pa), and have a multitude of penetrations in the installed air barrier system. ASTM E2357 verifies the air barrier system approach will stand up to the extreme weather conditions a building enclosure may experience during its lifetime






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ASTM E2357 Differs From Previous Test Standards

The ASTM E2357 test is also a far more realistic test because it includes multiple penetrations like a real building. The ASTM E2178 test is simply for materials, which is unrealistic because buildings always have penetrations.

At least one company uses the ASTM E398 test to evaluate vapor permeance of the membranes. This testing technology, invented more than 20 years ago for use by the packaging and medical industries, allows for faster, more precise measurements of water vapor transmission than the traditional ASTM E96 testing methods, while still allowing for comparison with ASTM E96 WVT (Water Vapor Transmission) values.

An assembled system, ASTM E2357, is tested according to criteria set forth by the performance guidelines of an assembled system.






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Approval by Air Barrier Association of America

The Air Barrier Association of America (ABAA) is the premier organization that verifies and approves the effectiveness of air barriers. Products should have this approval for optimum results in the building enclosure.

In April of 2015, ABAA approved membranes that are fully self-adhered, water-resistive barriers and air barriers with a cutting-edge adhesive that do not require primers, are void of VOCs, and can be applied in below-freezing temperatures.

This is remarkable because an ABAA category for such an innovative product did not previously exist, and thus a new category was created for Adhesive Backed Commercial Building Wrap. This presents further evidence that the design and manufacture of air barriers continues to evolve.






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Specifications and InstallationPhoto courtesy of Gluck+






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Questions to Ask When Specifying an Envelope Membrane System

To determine the best membrane for the building envelope, the architect, designer, or specifier should ask the following questions:

When choosing between self-adhered WRB/air barriers, peel-and-stick membranes with a primer, and fluid-applied barriers, what are the installed costs and total time in labor to complete the task?

When costing out a wall assembly, considering just the cost of the materials and not the labor cost for installation results in an inaccurate estimate. To accurately estimate the cost of the assembly, both the material and the labor should be considered. This should include the time needed to prep the sheathing to receive the barrier.

The following slides show an example. Note: material costs and labor rates will change depending on location.






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Cost of Assembly When Specifying an Envelope Membrane System

Assumptions: 40,000 sq ft, 200 windows

Materials

Self-Adhered, Vapor Permeable, Air Barrier Product Requiring No Primer

Self-AdheredProduct RequiringPrimer 1


Fluid-Applied Product No. 1

Fluid-AppliedProduct No. 2


Wall Membrane $39,600 $34,000 $51,200 $74,400 $74,250 $31,200

Window Rough Opening Treatment

$8,600

Seam Tape or Sheathing Sealant

$7,500 $7,500 $7,500

Primer Rollers/Pans $0 $9,956 $13,644 $13,644 $6,900

Liquid Applied Window Flashing

$0 $7,000 $5,950 $5,950 $7,000 $14,500

Total Materials $48,200 $50,956 $70,794 $101,494 $95,650 $53,200






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Cost of Assembly When Specifying an Envelope Membrane System

Assumptions: 40,000 sq feet, 200 windows

Labor Hours

Self-Adhered, Vapor Permeable Air Barrier Product Requiring No Primer



Fluid-Applied Product No. 1



Painting or Priming and Masking

200 200 480 480 240

Joint Preparation 75 75 75

Wall Membrane Installation

230 250 250

Window Flashing 120 150 150 150 150 175

Total Labor Cost (based on $60/hour)

$21,000 $36,000 $36,000 $42,300 $42,300 $29,400

Total Materials $48,200 $50,956 $70,794 $101,494 $95,650 $53,200

Total Project Cost $69,200 $86,956 $106,794 $143,794 $137,950 $82,600

Permeability 50 perms 18 perms/primer 15 perms 11.2 perms 21 perms 21 perms






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Is extensive field training necessary to install the product?

Increasingly, as skilled labor shortages affect the industry, installation errors tend to increase. Specifying a complicated,difficult-to-install product could lead to installation errors and increased failures, and consequently, risk. Ideally, the product should require minimal contractor field training.

How is the product affected by the weather?

Unless the project is in San Diego, California, or in a mild Mediterranean climate, the weather will impact installation. That means, for most of the country, periods of rain or freezing weather will occur. If the WRB/air barrier cannot be installed infreezing temperatures, the project could shut down until the weather improves. The cost of a shutdown could be exorbitant and would certainly disrupt the remainder of the construction schedule. Ideally, the product should be able to be installed in freezing temperatures.






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Is the membrane UV stable?

This question should be asked for several reasons. If there are construction delays, and the membrane is exposed for an extended time period before the cladding is installed, the membrane will be at risk of degradation from UV damage. It’s important to note for how long the membrane can be exposed; if there are exposed gaps in the sheathing, the membrane behind it should have superior UV performance.

What is the perm or drying rate?

The most effective vapor-permeable, self-adhering air barrier membrane will have the highest drying capacity. As the permeance increases, so does the drying capacity.

In terms of sequencing, when can WRB/air barriers be installed? Can the WRB/air barriers be installed before or after the roof? When walls are dry?

This material has the flexibility to fit anywhere in the building schedule.






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What is its compatibility with other materials?

This is the emerging issue with new products that come on the market. While the material itself might perform well, it needs to be compatible with the substrate and cladding. Check to see if the barrier is compatible with the most common substrates:• Exterior gypsum • Rigid insulation • Precast concrete • Concrete block • Cast-in-place concrete • Plywood • Pre-painted steel • Galvanized metal • Aluminum (painted, mill)• Anodized aluminum • Rigid vinyl

The exterior cladding must also be considered. Many buildings use multiple types of cladding to create architectural visual appeal, so for ease of installation and construction schedule, a single WRB/air barrier should perform behind multiple types of cladding.






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Wall Preparation

For proper installation of the self-adhered WRB/air barrier membrane, all surfaces must be dry, sound, clean, and free of oil, grease, dirt, excess mortar, or other contaminants detrimental to the adhesion of the water-resistive air barrier membrane and flashings. Trades workers should fill voids and gaps in substrate greater than ⅞″ in width to provide an even surface.

Additionally, a self-adhered WRB/air barrier should have a ventilated, unimpeded vertical drainage cavity or rain screen system to be incorporated into all installations. Although it’s not required, drainage is preferred because the drainage plane allows the water to leave the structure. The membrane manufacturer likely offers compatible and corresponding accessories to accomplish this, as well as flashing materials for window and door rough openings, and flashing materials for transitions.






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Limitations

While most self-adhered, water-resistive, vapor-permeable air barrier sheet membranes are quite durable, there are some general and practical limitations. Many carry recommendations to be installed in temperatures no lower than 20°F. Contamination of the wall and building site will adversely affect the membrane’s water resistance. Many of these membranes should not be subjected to asphaltic materials, chemicals, surfactants, or cleaning compounds that could affect the water resistance of the membrane surface; if exposed, replace the affected membrane.

Please remember the exam password MEMBRANE. You will be required to enter it in order to proceed with the online examination.






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Green Credentials






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Overview: LEED® Certification

The U.S. Green Building Council (USGBC) is a 501(c)(3) nonprofit organization composed of leaders from every sector of the building industry working to promote buildings and communities that are environmentally responsible, profitable, and healthy places to live and work. USGBC developed the LEED ® (Leadership in Energy and Environmental Design) green building certification program, the nationally accepted benchmark for the design, construction, and operation of high performance green buildings.

LEED credit requirements cover the performance of materials in aggregate, not the performance of individual products or brands. Therefore, products that meet the LEED performance criteria can only contribute toward earning points needed for LEED certification; they cannot earn points individually toward LEED certification.

For detailed information about the council, their principles, and their programs, please visit www.usgbc.org.

http://www.usgbc.org/






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Green Building Attributes

There are several factors that make a self-adhered, water-resistive, vapor-permeable air barrier sheet membrane beneficial to an architect’s sustainable building goals. If one is trying to meet the criteria of the Living Building Challenge,look for a membrane that is void of all indicated red-list chemicals, and has a Declare label. Referred to as a "nutrition label" for building products, Declare labels list all of the materials found in a given product, as well as its assembly site, life expectancy, and other key details to facilitate informed decisions toward positive human and environmental health.

A desired membrane might be highly UV resistant, which means it can remain fully exposed for up to 180 days prior to installation of the cladding system. An open-joint cladding system requires the membrane to be UV stable.

Also, a self-adhered, water-resistive, vapor-permeable air barrier sheet membrane protects against water intrusion, but allows building materials that may have become wet during the construction phase to dry out, reducing the risk of wood rot, deterioration, or corrosion.






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Green Building Attributes

In the USGBC LEED® Green Building certification program, a self-adhered WRB/air barrier membrane can contribute to credits that address low-emitting materials such as adhesives and sealants.

At the National Renewable Energy Lab in Golden, Colorado (pictured right), the only national laboratory solely dedicated to advancing renewable energy and energy efficiency technology, a self-adhered, water-resistive, vapor-permeable air barrier sheet membrane was chosen to protect the building envelope. The membrane is 100% recyclable, has zero VOCs, and doesn’t require a primer, which contributed to the lab achieving LEED Platinum status.

The self-adhered, vapor-permeable air barrier membrane contributed to the building’s overall energy efficiency by being part of the continuous air barrier system.






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Summary and Resources






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Summary

There is an art and a science to designing and constructing buildings that are beautiful, comfortable, healthy, resource efficient, and durable. An effective building envelope is critical to a building that will last and reduce the architect’s risk.The water-resistive, air barrier should stop air and resist water. In addition, the installation should be compatible with today’s level of skilled labor, and embody qualities that allow it to be installed in freezing weather without the deploymentof extensive equipment or pollutants. Using the proper foundational materials will result in a beautiful and functional building that will last for many years.






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Resources

“Federal Center South Building 1202.” The American Institute of Architects. American Institute of Architects, 2016. Web. http://www.aiatopten.org/node/204 Accessed May 2016

Living Building Challenge. International Living Future Institute, n.d. Web. https://living-future.org/lbc Accessed April 2016

https://living-future.org/lbc

http://www.aiatopten.org/node/204






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Conclusion

If you desire AIA/CES, state licensing or CE credits for another organization, please click on the button to commence your online examination. A score of 80% or better will allow you to print your Certificate of Completion; you may also go to your AEC Daily Transcript to see your completed courses and certificates.

For additional knowledge and post-seminar assistance, click on the Ask an Expert link above.

If you have colleagues that might benefit from this seminar, please let them know. Feel free to revisit the AEC Daily website to download additional programs from the Online Learning Center.

©2016 VaproShield. The material contained in this course was researched, assembled, and produced by VaproShield and remains its property. “LEED” and related logo is a trademark owned by the U.S. Green Building Council and is used by permission. The LEED® Rating System was authored by and is the property of the USGBC. Any portion of the Rating System appearing in this course is by permission of the USGBC. Questions or concerns about the content of this course should be directed to the program instructor. This multimedia product is the copyright of AEC Daily.

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