Insulating Above a Roof Deck
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Hello,
We plan to insulate above our roof deck in Hawaii (2:12 pitch over most of the home, low/flat over a 20×15′ section) with Polyiso.
We then planned for a torchdown layer + white reflective coating (silicone – GACO, or acrylic – Western Colloid 720ARC).
However, I recently came across this product — FIRESTONE ULTRAWHITE
https://www.firestonebpco.com/us-en/roofing/asphalt-roofing-systems/ultrawhite-granulated-cap-sheet#
Comparing SRI (new/aged), it looks pretty good. Gaco is much higher initially, but does loose this over time (assumes no cleaning):
Ultrawhite Cap Sheet SRI: 89/77
GACO S-20 SRI: 111/76
Western Colloid 720 ARC SRI: 84/75
QUESTION: What are thoughts on using a product like the Firestone Ultrawhite vs coating over this layer (torchdown)?
Thanks for any thoughts and advice as always!
Andrew
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Replies
After more research and talking with local roofing supply, it looks like Polyglass Polyfresco is another reflective capsheet worth looking at.