Replies

1. GBA Editor
   Martin Holladay | Oct 02, 2014 03:51pm | #1

   Daniel,
   The only generic material approved by the ICC-ES for use as a water-resistive barrier (WRB) is asphalt felt. Every other material has to be individually submitted for approval by a material manufacturer. So the simple answer to your question -- "Has expanded polystyrene been approved as a WRB" -- is No.

   If you read my article on the topic (Using Rigid Foam As a Water-Resistive Barrier), this information should be familiar to you.

   At the time I researched that article, I only found evidence of one EPS manufacturer that had gone through the process of getting an EPS material approved for use as a WRB by the ICC-ES. The product is Insulfoam R-Tech, and it has been approved for use only under stucco (and not under any other types of cladding).

   If you are a homeowner, a builder, or an architect, tracking down a copy of AC71 won't do you much good.

   If you are a manufacturer of EPS who wants to go through to approval process -- a process that isn't cheap, because it requires laboratory testing -- you can dig deep into the AC71 requirements if you want.

   Here is a link to the AC71 document: ACCEPTANCE CRITERIA FOR FOAM PLASTIC SHEATHING PANELS USED AS WEATHER-RESISTIVE BARRIERS.

2. GBA Editor
   Martin Holladay | Oct 02, 2014 04:25pm | #2

   Daniel,
   Sorry -- I forgot to answer your question about installing insulated vinyl siding. To learn about installation requirements for these products, contact the siding manufacturer. Most siding manufacturers publish their installation instructions online.

   Here is one example: Installation instructions for insulated vinyl siding manufactured by CertainTeed.

3. 
   djnealon | Oct 02, 2014 09:13pm | #3

   Thank you, Mr. Holladay. I am a complete newbie to these issues. Your answer(s) were very helpful.