crawl space insulation
Spray on foam or solid styrofoam. low clearance crawlspace. Only 12 years old. Heard foam can allow wood to rot. Every contractor seems to have a different system or opinion. 19 X 25 foot crawl space.
Either method will work though sprayed on foam is generally easier to apply & get a better job. One big item is making sure the area is ventilated quite well while the work is going on & if utilizing spray foam, no one is home & the house is pressurized. Foam does not allow wood to rot, moisture does that so you need to make sure you have an adequate vapor barrier placed on the ground & that laps up the wall. Any other moisture sources need to be corrected, vents closed & sealed (leaking pipes, incorrect grade, etc...) and the wood / space is dried out. As for the foam - closed cell only so it doesn't hold any moisture. Along those lines make sure the rim joist areas are sprayed or filled in properly. Do not forget that per codes a supply line must be utilized. For more you may wish to read up on "sealed crawls" especially from Building Science .com