# Minimum R vs. Average R-Value



## Mr Single Ply (Dec 22, 2010)

Will an average R-Value, let's say 20, on a fully tapered roof give you the same energy results/performance for the building as flat R-20 insulation on a roof with the slope in the deck?
Thanks


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## 1985gt (Dec 21, 2010)

Short answer, not really. If you have a straight taper Iso for an avg R value of 20 on the high side you would have Aprox 6.50 inches of ISO, on the low side 0" the low side would lose alot of heat, the high side would not. 

On a sloped deck with 3.25" of ISO (R-20.10) it would be the the same the whole way across. 

Hope this helps?


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