Thread: Thermo-ply Requirement

My wife and I just moved to Austin (Texas) and are in the market to buy a new home. We have been looking at fairly large homes, about 3,000 square feet, and are worried about the cooling of such a large house during the summer. We tried to address this concern with several different real estate agents, but have gotten mixed responses.

From what we have been told, there is a material that is put on the exterior of the house before finishing. This material, so we have been told, is called thermo-ply. However, whether this material is required on houses has been a subject of confusion. One realtor told us that only one builder, Centarra, actually wraps their homes in this. Another realtor said that all homes are required to have this, but only if they were built post 2009. A third realtor told us that all homes are required to have this.

Does anyone know the truth?

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Thermo-Ply, Thermo-Sheath, etc are thin structural panels designed to replace plywood for sheer wall reinforcement. There are four grades by color to choose from. Because of the construction, this material makes an excellent air barrier, has a low perm rate, low flame spread and is a poor food for mold. It's what I use to line fireplace chases inside and is a marvelous material. It's the thickness of cardboard but many times stronger. It can be cut with a knife but isn't easy.

There are several reasons they could be using this product so I'd ask your local building dept. if there is any local ordinance specifying a thin structural panel with seams taped. Otherwise, the regular building code applies which has many alternatives.

Originally Posted by Michael Marx

My wife and I just moved to Austin (Texas) and are in the market to buy a new home. We have been looking at fairly large homes, about 3,000 square feet, and are worried about the cooling of such a large house during the summer. We tried to address this concern with several different real estate agents, but have gotten mixed responses.

From what we have been told, there is a material that is put on the exterior of the house before finishing. This material, so we have been told, is called thermo-ply. However, whether this material is required on houses has been a subject of confusion. One realtor told us that only one builder, Centarra, actually wraps their homes in this. Another realtor said that all homes are required to have this, but only if they were built post 2009. A third realtor told us that all homes are required to have this.

Does anyone know the truth?

There is no requirement for this. If you want a house that will stay cool the house needs proper insulation and a properly sized HVAC system. You should look at SIP construction and or homes that have been insulated properly with a closed cell foam product.

Take what the real estate agents say with a grain of salt and do your own due diligence like you are doing now. Hire an experienced home inspector that you find on you own before you sign on that dotted line.

Originally Posted by Kevin Wood

We just started requiring this in the the Ontario Building Code. Energy Efficiency is here to stay.

Your code started requiring Thermo-Ply, Thermo-Sheath by name?

Originally Posted by Kevin Wood

No Jerry of course not. It is recommended to wrap with insul foil of any kind to improve the efficiency.

Kevin,

That is similar to what I thought might be in the code, but "insul foil" is not what that stuff is.

Major distinction here:
thin structural panels are just that--structural. Any weatherization benefits are secondary.

Jiffy Pop wraps are not structural. Depending upon your climate some things you want and some things you don't. For instance, you don't want a vapor barrier on the outside wall in a cold climate but rather at the inside paint.

T-ply does breathe a little and experience has shown that when used in proper applications, there are few if any repercussions.

You need clarification on what they are requiring: air barrier, R-values, etc.

Over the past several years Austin has been implementing some uncommon requirements in attempts to save energy. Unless a responder is familiar with Austin's unique requirements, the only correct answers are either inquire of the code enforcement office or study the local documents.