Vapor Permeable and Non Permeable Air Barrier Systems

We are starting to see more building owners interested in air and vapor barrier systems, both fluid applied and sheet applied. These systems are related to the entire building envelope, from foundation to walls to rooftops, and have been proven to increase energy efficiency and improve air quality.

Air barrier materials resist air leakage and are designed to form a continuous plane around a building to protect uncontrolled air movement in and out of the building envelope.  Air leakage loads are significantly greater than most designers and architects realize, and a study on air barriers by the National Institute of Science and Technology revealed that the right air barrier can help improve building performance by reducing heating and cooling costs by as much as 36%.*

Vapor barrier materials limit the amount of water vapor diffusing through the wall as a result of vapor drive. Vapor drive is a phenomenon that occurs when water vapor naturally diffuses into and through wall structures and is controlled by type of structure, porosity, moisture gradients and temperature gradients.

Remember science class and studying about thunderstorms? This is the same thing just on a molecular level. It incorporates the key principles of air movement: from warm to cold. In a cold climate, vapor drive is primarily from interior of a building to exterior. If you have a hot, humid climate, the vapor drive is primarily from exterior to interior.

Source: Buildingwell.org

There are countless scientific studies and published documents about water vapor, vapor drive and air movement. With the advent of modern building science, it has been found that air leakage - and not vapor diffusion - is the real problem. The air barrier systems we incorporate, however, are a combination of both which afford us the ultimate in design flexibility. **

To manage vapor diffusion there are two types of air barrier membranes: Vapor Permeable and Non-Permeable.

Vapor Permeable Air Barriers
High vapor permeance keeps air and water out, while allowing water vapor to escape.  Positioned anywhere within the wall assembly, they are watertight and protect against air leakage. 

Non-Permeable Air Barriers
These membranes act as air barriers, vapor barriers and rain barriers. When positioned on the warm side of the insulating layer, they serve as an efficient vapor barrier, preventing moisture condensation through the wall cavity. Good for hot humid climates or an extreme mixed-humid climate.

Non-Permeable Air Barrier
Source: Henry Products

The choice of product, between a vapor permeable versus a non-permeable air barrier, is dependent on a wide range of factors, like those mentioned above, and advancements in available materials make it important to work with a professional.

*NIST Report 7238

**The Difference Between a Vapor Barrier and an Air Barrier. Written by R.L. Quirouette, Building Practice Note No. 54, July 1985

Other Sources: 
Solving the Air Barrier Riddle: Permeable or Impermeable? Written by Sonya Santos and published in the Journal of Architectural Coatings, Jan-Feb 2007

Water Vapor Migration and Condensation Control in Buildings. Written by William Acker and published in HPAC June 1998

An Energy Conservation Idea for Building Owners

We have always been interested in energy conservation, which is one of the things that got us started with Spray Polyurethane Foam Roofing in the first place over 35 years ago. Though out the years we were naturally led to maximizing an owner's investment through quality products and installation for the entire building "envelope," which then started to include Polyurethane Foam Air Barrier and Fluid Applied Air Barrier services.

For building owners and our clients it all boils down to this: decreasing your energy consumption and increase profits while protecting the health of the occupants.

As there are many ways for to accomplish this, we found an article interesting in the Commercial Construction & Renovation July/August 2012 issue which talked about ways to reduce building HVAC costs with site-recovered energy by using Energy Recovery Wheel Technology, or Enthalpy Wheels.

According to the article, enthalpy wheels "transfer energy by rotating between outdoor air and exhaust air streams to transfer heat and moisture from one airstream to another." It retrieves the wasted energy in building exhaust air and recycles it and allows the building to increase outdoor air levels without making your HVAC unit work harder.

It also helps enable building owners to participate in energy programs. Energy recovery wheels are available from most HVAC OEMs and distributors.

The Difference Between Air Barriers and Vapor Barriers

We don't want to bore you too much technical jargon but it is important to understand that there is a difference between air barriers and vapor barriers.

A vapor barrier is designed to restrict the flow of water vapor through a material. The air barrier, on the other hand, restricts the flow of air through a material.

Since they are intended to control the rate of diffusion into a building assembly, water vapor material will control the rate of moisture flow where they are placed. They don't have to overlap or be continuous.

Then there are water resistive barriers, which are systems using materials primarily designed to keep liquid water from entering the building enclosure. They are designed not be be a vapor barrier and are designed to be installed on the cold side of the insulation.

To make it even more confusing, combined air barriers, vapor barriers and water resistive barriers can be provided in a single material.

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It's important to know when you are dealing with the building envelope which material you choose to perform each different function.

But, that is what we are for, so when you are looking to design your air barrier system for your building, give us a call and we'll worry about all of that for you.

Why Is it Important for You that We are ABAA Certified

Washington Roofing & Insulation is an accredited contractor of the Air Barrier Association of America (ABAA).

Washington Roofing & Insulation

In order to become accredited, we completed intensive requirements such as attending courses and passing written exams. Furthermore, in order to be a part of the ABAA, companies must have a minimum of $300,000 bonding ability, over $2 million in general liability insurance, be specifically licensed, have a minimum of 3,000 hours of air barrier field installation or related trade experience and pay an annual membership.

That's all great, you say, but what does that mean for me?

It means that we undertook this challenge as a company to bring a higher level of commitment and professionalism in the installation of air barrier systems for our clients.  It means that our installers have thousands of hours of experience and have been trained specifically on proper installation of this product, and it means that we undergo continuing education and stay up-to-date on trends in air barriers and building envelopes.

Therefore, you will receive a superior end product when Washington Roofing & Insulation works with you to provide the air barrier system for your building.

And that's the bottom line.

Jammin' With Jam-Ex

It is usually the little things that companies do that build their reputation. One of the ways we go that extra mile is utilize products during installations that may not seem like a big deal, but provide a quality, long-lasting end result.

One of those products is called Jam-Ex. Is is a simple thermoplastic piece used to extend jambs, heads and sills of windows, curtainwalls and doors in exterior walls of buildings for air and vapor barrier systems.

We use them around windows sills to maintain an even spray flow across the entire area. No matter how well trained you are, installers will tamper the flow as they near an opening, causing a thinner air barrier around the windows and doors. Jam-Ex prevents this tapering. It also helps prevent wood warping since it is fabricated from a custom blend of resin modified, UV resistant thermoplastic.

It is not exciting, sexy or expensive. It doesn't shake hands, kiss babies or run for president. It is just a little something extra that helps provide a higher quality product and service for our customers.

Flint Hills Discovery Center Project Complete

The Flint Hills Discovery Center project is complete.

We are proud to pass along the announcement that the grand opening for the Flint Hills Discovery Center in Manhattan, Kansas is right on schedule for this April. The Center broke ground in July 2010 with a mission to "celebrate, explore and care for the flint hills."

Back in November we had posted how Washington Roofing and Insulation (WRI) was working with Split Rock Studios out of Minneapolis to create a cave at the center for people to walk into and see exhibits. This was done by spraying polyurethane foam inside the structure and then the creative people at Split Rock made the "cave like" appearance by cutting into the foam and adding the vines. WRI finished the project by spraying polyurethane foam inside the walls of the cave and then using Flame Seal TB on top of the foam to create the thermal barrier needed to meet fire requirements. WRI also sprayed foam on the walls of the center.

Inside the cave during construction.

Moriah Carpenter, project estimator for the company, said that this was one of the more unique projects WRI had ever done.

"What is done behind the scenes makes a big difference," she said. "It will really help them with their energy efficiency. It was exciting to be a part of it and watch it all come together."

The Center is hosting a Contractor's Grand Opening on April 7th and then will be open to the general public shortly after that. 

"McCownGorden worked hard to get this open on time," Moriah said. "They did a fantastic job."

Inside the cave with exhibits.

Another shot of the cave's interior with exhibits.

Note: Photos compliments of the Flint Hills Discovery Center construction page

Give Your HVAC Unit a Break

How much money do you spend a year on your heating a cooling for your building? Commercial energy consumption has always been high but heating and cooling can be a bill you dread receiving. Much of the costs associated with these inflated numbers are due to air leaks in your building.

Many companies now are looking into air barrier systems for their building, which is also considered a "building envelope." The building's six sides are wrapped in layers comprised by a number of different materials which helps prevent air leakage and the diffusion of air caused by wind and other sources. It assists in keeping the warm air in during the colder months and the cool air in during the warmer months. It can also help with the prevention of mold and other pollutants that can be potentially harmful to people within the structure.

Application of the Walltite foam air barrier system at
the University of Missouri School, Columbia, Missouri.

Air barrier system envelope protects entire building.

The Department of Energy says that air leakage can increase energy costs by up to 40% in colder climates and 15% in cooling costs. A good air barrier system can reduce these costs. In fact, since mechanical engineers design the HVAC units in buildings around air leakage, many times they are able to use smaller units when a building has a good air barrier system in place.

So give your HVAC unit a break and look into air barrier systems for your next building design or renovation. It will help your pocketbook, as well.

Up On the Roof Top

We have been "up on the roof top" now for over 35 years and have never been mistaken for Ol' St. Nick, albeit we would find it to be a complimentary identity mishap. The jolly man himself may have a bigger service area and a larger target audience but our mid-western clientele is pretty extensive with places in Texas, Oklahoma, Texas, Iowa and of course, Kansas.

We have met some fantastic people along the way, and they are all pretty satisfied with their polyurethane spray foam roof systems or their air barrier systems for their commercial buildings.  This last year has been quite a ride. We became Air Barrier Association of America (ABAA) accredited to install Air Barrier systems and, along with many others, are currently working with the Beta Theta Pi Fraternity House at the University of Missouri in Columbia, Missouri.

But aside from all of that, we want to wish everyone happy holidays and the best for the 2012 new year. We are looking forward to being "up on the roof top" for many more years to come.

The WALLTITE® Air Barrier

WALLTITE® is a premium spray-applied polyurethane foam insulating air barrier system manufactured by BASF. WALLTITE® is seamless and self-adhering, eliminating uncontrolled air leakage by providing monolithic coverage with superior insulation R/U-value.

The graphic below shows how the closed-cell, WALLTITE® Air Barrier is positioned to substantially reduce both air leakage and moisture permeance through the building envelope.

Source: BASF

WALLTITE® is approved by the Air Barrier Association of America (ABAA) and acts as an air barrier as part of the total building envelope. Washington Roofing and Insulation is a Q1 applicator with BASF and an ABAA accredited ABAA.

Source: www.spf.basf.com

Comparing Insulation Products

Out of the dozen positive features compared between spray foam insulation, fiberglass batts, fiberglass loose-fill, wet-sprayed cellulose, blown-in (dry) cellulose and mineral wool, only the spray foam insulation had the most. They include:

• High to Highest R-Value per inch
• No wind washing effect
• Certified air barrier
• Expands to fill hard-to-reach spaces
• Contains no HCFCs or CFCs
• Does not contain formaldehyde
• Won't shrink or settle over time when properly installed
• Will not absorb significant levels of water
• FEMA approved flood-resistant insulation materials
• Will not distort framing when properly installed
• Efficiently reduces sound transmission through walls

The only feature that Spray Foam Insulation does not have that two of the others provide is the ability to inject it into existing wall cavities without major demolition. Spray Foam Insulation is normally done during the initial building process, while adding on to an existing structure or remodeling.

Source: sprayfoam.com, "Insulation Comparison Chart"

What is Spray Polyurethane Foam Roofing?

Spray polyurethane foam, commonly referred to as SPF is a spray-applied insulating foam plastic that is installed as a liquid and then expands many times its original size. Spray polyurethane foam can be adjusted and have many different physical properties depending on the use desired.

For example, the same basic raw materials that can make insulation foam semi-rigid and soft to the touch also creates high density roofing foam that is resistant to foot traffic and water. Specialized equipment is used to apply the spray polyurethane foam and proper technical training is important in order to get the best results.

For roofing, spray polyurethane foam insulates and eliminates thermal bridging through fasteners or gaps in decking while providing a long-lasting roofing system that has a life that can be extended by re-coating or recovering in an average of > 10 – 15 years. As a result spray polyurethane foam is used in a wide variety of applications including, but is not limited to:

• Roofing
• Air barriers
• Commercial and residential insulation in walls, ceilings, attics and basements
• Industrial insulation for pipes and tanks, cold storage facilities, freezers, walk-in coolers, and climate controlled buildings such as produce storage and clean rooms
• Flotation for boats, ships, barges, floating docks, etc.
• Higher density spray polyurethane foam has been used to increase the structural strength of wings in airplanes.

For more information on Spray Polyurethane Foam Roofing in Kansas, Iowa, Oklahoma and Texas, please visit http://www.washingtoncompaniesinc.com/what-is-spray-polyurethane-foam.html.