It can cause mositure trapping as well, houses need to breathe and this is like wrapping the house in a sealed bag. There are instances of mold and mildew where improper installations sealed the house too well, so be sure to discuss with any contractors

Icynene is a brand I've specified frequently for projects. You want to make sure you have a good installer which you can find from their list of approved contractors. The installation process is a bit more difficult than with other types of installation and the biggest problem is that it's really messy to install. The area in question has to be really well sealed off from the rest of the house or droplets of expanded foam will get everywhere. The product works great, forms a better insulating barrier and has a much higher R-value per inch than other insulation types. However it is much more expensive. People also claim that chemical off-gassing is a concern but those are generally unsubstantiated rumors.

Has anyone had any experiences (good or bad) with installation of spray foam insulation? Recommendation are appreciated. We have a flat room with crawlspace that we would like to have done. Thanks!