
Perma "R" Products R- 7.8 , 2-in x 4-ft x 8-ft Faced Polystyrene Board Insulation
4.5
209 Questions
Read All Questions & AnswersIs the R-value for this foam really only 7.7 (which equals R 3.85 per inch)? Most rigid foam is at least R 5 per inch.
1
rigid polystyrene is more dense and has a higher R value.
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