EPS over polyiso on reroof?
So based on everything thing I am reading should we be using R3 R4 or R5 for each inch of Polyiso since it decreases in performance as it gets colder. I seem to be seeing some variation in Answers. I am in zone 5 and was planning on putting 5 inches of Polyiso.(thinking that was R 30 Roughly but if is is only R 15 when coldest that is a problem) Now it seems like I would be better served with three inches of polyiso with EPS on top. I have access to 1.5 or 2.75 inch EPS. Would I still be OK with 3 inches of polyiso and 2.75 inch of EPS on top?
Posted Aug 29, 2014 6:33 PM ET
Edited Aug 30, 2014 6:33 AM ET
Other Questions in Energy efficiency and durability
Has anyone used a WhisperComfort™ Spot ERV Ceiling Insert Ventilator FV-04VE1 in high performing home?
I plan to build a passive solar, earth berm home , having trouble finding out how big (diameter) and length of the earth tube to ventilate a 1500 sq ft home