<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><pre style="-webkit-text-size-adjust: auto; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">THanks Peter</pre><pre style="-webkit-text-size-adjust: auto; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">I don’t know what’s going on under there…. Will see in the summer, but the epdm developed some pinholes causing tiny leaks. So I don’t think it’s enough to address from inside…. </pre><pre style="-webkit-text-size-adjust: auto; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);"><br></pre><pre style="-webkit-text-size-adjust: auto; caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">To be clear, this is a structural issue, not a thermal issue; ie. the
polysio has degraded to the extent that it no longer supports the deck.
If so, you could use any number of structural boards like the one
Norbert suggested or perhaps this Rockwool product
(<a href="https://www.rockwool.com/north-america/products-and-applications/products/comfortboard-110/#Specifications&Sizes">https://www.rockwool.com/north-america/products-and-applications/products/comfortboard-110/#Specifications&Sizes</a>
).
If the polyiso is structurally sound and will likely remain so, can you
remove the drywall and insulate from below, using a closed cell spray
polyurethane foam? I think the closed cell foam is about R6/inch and
should meet the thermal, air and vapour code requirements of your area.
It may be cheaper than removing the polyiso, plywood, epdm, sleepers and
decking.
All the best,
Peter</pre><div dir="ltr">Sent from my iPad</div></body></html>