The R-value of closed-cell spray foam insulation is around 6.5 to 7 per inch, and the R-value of open-cell spray foam insulation is around 3.8 per inch.
While it is true that spray foam insulation does have an off-gassing period following installation, this effect is only temporary. After around 24 hours, the off-gassing should stop.
Installing spray foam insulation is more complicated than installing other insulation materials, such as fiberglass or mineral wool. While it is technically possible to install spray foam insulation on your own without the help of a professional insulation company, it is highly discouraged for several reasons.
Homeowners will be happy to discover that, when installed correctly, spray foam insulation should last the entire lifespan of their homes. Once it hardens, spray foam will retain its shape indefinitely and not lose its R-value over time.
Spray foam typically takes 8 to 24 hours to expand.