I received the following letter from Todd Kuykendall, Director, Product Management at Georgia-Pacific Gypsum about my article titled “Design and Installation Tips for Single-Ply Roofing Systems”
Dear Roofing Contractor:
I enjoyed the article, “Design and Installation Tips for Single-Ply Roofing Systems” in the January 2012 issue. However, I wanted to bring one thing to your attention that I think was misstated. In “Tip #11” of the article, author Mike Russo mentions the following:
11. Structural fiberglass-faced gypsum board should not be used as a substrate for fully adhered attachment on parapet walls.
I believe the phrase should have been worded:
11. fiberglass-faced gypsum sheathing boards should not be used as a substrate for fully adhered attachment on parapet walls.
The term “structural” is confusing because gypsum sheathing and gypsum roof boards are not structural. The correct product for the parapets is 1/2 inch (minimum) primed glass mat roof boards (i.e. DensDeck® Prime). I mention this because there has always been a lot of confusion over the appropriate product to use on parapet walls. Let me know if you see it differently, or I misinterpreted the wording.
Director, Product Management
Mike Russo responds:
Thanks for pointing this out, Todd. You are correct. A primed glass mat roof board would be the product to specify as a substrate when fully adhering TPO or PVC roofing membranes to parapet walls.