EPS rigid foam board: R-value per inch
Short answer
EPS rigid foam board adds about R-3.8 per inch, so you need roughly 7.9" for R-30 and 12.9" for R-49.
R-value per inch
R-3.8
Best for
Continuous exterior sheathing (budget)
EPS rigid foam board thickness chart
| Target R-value | Thickness needed |
|---|---|
| R-13 | 3.4" |
| R-19 | 5.0" |
| R-30 | 7.9" |
| R-38 | 10.0" |
| R-49 | 12.9" |
| R-60 | 15.8" |
How much for your home?
Calculate eps rigid foam boardOther materials
Frequently asked questions
How many inches of eps rigid foam board do I need for R-49?
About 12.9" of eps rigid foam board, since it adds roughly R-3.8 per inch (R-49 ÷ 3.8).
What is the R-value of eps rigid foam board per inch?
EPS rigid foam board provides about R-3.8 per inch (a typical value — density and brand vary). So 7.9" gives roughly R-30.
What is eps rigid foam board best used for?
Continuous exterior sheathing (budget). Compare it against other materials for your target R-value in the calculator.