We have just had a home energy audit and I am interested in insulating the crawl space. The auditor suggested using foam board on the concrete and pink batting in the joist spaces above the foundation wall. There is already a vent from the heating duct in to the space. If I use something like tiger foam, can I use it over top of a 2" foam board to increase the R value of the crawl space when I can shell out more money for it?
If you live in an older house and have not done so, I highly recommend getting an energy audit done. The potential savings for getting things done is impressive.