The 34th annual showcase of the National Association of Home Builders' opened to the public for tours on Jan. 10, coinciding with the start of the International Builders' Show. TNAH is a yearly project to use the latest design trends and construction techniques to inspire builders.
While not among the obvious amenities, plastic building materials play important roles in creating an exterior envelope that is so tight, energy use is minimized and pest control is maximized. The builders used a new open-cell spray foam by Icynene Inc. that is low in volatile organic compounds, which improves indoor air quality while boosting energy efficiency, as well as a tough new insect barrier wrap by Polyguard Products Inc. called Term.
Polyguard CEO John Muncaster said the wrap, which was developed with entomologists at Texas A&M University, has a thick polyethylene backing to keep bugs, particularly termites, at bay. The top layer is made of a polypropylene fabric so concrete can bond with the fibers if it's used as a barrier for the underslab, which is a common entry point for subterranean termites. A proprietary sealant is used to hold the plastic fiber and film together.
“This has been tested long term in the lab and in the field and it resists termites,” Muncaster said. “We don't why. We don't know everything about what makes them tick.”
The combination of the sealant and two plastics simply can't be penetrated by voracious-eating termites. The three materials seem to have sound-deadening qualities for the insects, and that could be factor, Muncaster said, or it could be related to the barrier's odor and moisture control.
“We're putting the house in a sealant bag, really,” he said. “Not only the bottom, where so many insects come in, but up the walls at the seams there can be openings. Our goal is to seal all gaps wherever possible. You can almost keep all insects out.”
In new construction, if incorporated into the design stage, the Term system can seal plumbing openings, bath traps, base flashing, window flashing, vent holes, flooring underlayment and joints in addition to foundation and underslab barriers. No system can keep out every bug, but this one comes close, Muncaster said.
In remodeled houses, the Term system can protect sill plates, seam and window flashing, underlayments for replaced floors, and more if it's a major renovation.
“We think it has the potential to take sustainable construction up another level and help people live better and more comfortably,” Muncaster said, noting that water and energy conservation have long been goals of green builders. “We've got something new. I don't think anybody in America has ever taken a systems look at construction to exclude insects and other pests. That's what we're doing.”
Polyguard's barrier system also was used at the 4,631-square-foot the New American Remodeled Home (TNARH), which NAHB did this year for the first time since 2007. It's in the same gated community.
Another innovation at the TNARH: Boral Roofing's elevated batten system, which is made of wood with plastic pads made of recycled polyethylene. Boral's concrete tiles are mounted on the elevated battens to allow for the free flow of water underneath. If water dams above standard battens because of broken tiles or failed flashing, it could cause a roof leak.
The elevated battens also let air flow from the eaves to roof ridges and hips. This ventilation cools the roof during hot weather.
In addition, TNARH has high-end drywall by Certainteed, including SilentFX in the bedrooms and bathrooms, which is a viscoelastic polymer material that is sandwiched between two layers of drywall for noise reduction.
Both homes are projected to achieve Emerald status, which is the highest of the four levels of green building recognized by the ICC 700 National Green Building Standard. Other anticipated certifications for both homes include the Department of Energy's Energy Star, Builders Challenge qualified/Build America Program, EPA Indoor airPLUS qualified and the private Wellness Within Your Walls designation.