Experts Weigh in on Air Leakage Considerations for Contract Glaziers
March 1, 2011

When it comes to today's construction, failure of the building envelope is a challenge for many, including contract glaziers. And air leakage, for example, is a significant concern, and one not always thought of by the glazing industry.

Marcy Tyler, technical applications manager for Tremco, says North American building envelope repair is a multi-billion dollar industry and most problems are moisture-related, caused by air or moisture leakage.

"Most façade problems relate to terminations and connection details and 70 percent of all construction litigation is related to façade leakage," she says. She explains that most air leakage failures do not occur through an opaque wall, but rather walls with windows. It is not about the wall, she says, but about how dissimilar components come together. And this, she points out, is becoming a big consideration for the glazing industry.

Craig Carson, vice president of A-1 Glass Inc. in Englewood, Colo., says that in learning more about how walls with openings actually perform and where the improvement of the wall must come from, "it is obvious that there was energy loss at the window (or storefront, or curtainwall) perimeter conditions that needed to be addressed.

"Thinking of ourselves as building envelope contractors and not just glazing contractors forces us to be involved with the total design of the wall."

He points out that lack of a secure air barrier, can ultimately be a concern for glaziers. Carson says his company has taken measures to handle such situations.

"Our experience with these new concepts demands that we install the glazing frames before the finish exterior wall product is installed. We have been promoting this concept for years and we are seeing general acceptance of this change to the former means and methods of building walls," he says. "Our biggest resistance had come from the masonry contractors, but as the architects and general contractors began to realize that this was the only practical way to properly seal the window systems, by having full access to the perimeter conditions, the masons have been forced to revaluate their position and accept that their installation must follow the glazing."

But as Tyler points out, determining which party - the contract glazier or the water proofer, is ultimately responsible for the air barrier is sometimes a challenge.

"There's a disconnect as to who is responsible," she says. "If there's a leak, who gets the call?"

Carson says that they simply accept the responsibility for what they install.

"However, we also make sure that testing of all materials is done in the manufacturer's labs and [we] double check [that] in the field," he says.

While staying informed and aware of such issues is important for contract glaziers, there are also measures they can take to make sure they are covered in case there is an issue of air leakage.

"Certainly the times are changing, and along with this, new and better methods of construction make better walls. I feel that it you do not investigate, study, educate and embrace new methods you will be bypassed by those who do," says Carson. "This is a very competitive business, and if you are unwilling to learn and only want to stay in your comfort zone of what and how you may have been installing products, you can slowly watch as your business dies."

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