Crawl Space Reflective Insulation

Arnold1949 asks,

I am building a house in Cleveland, TN. What is your opinion of using a product called Prodex for crawl space insulation between the floor joists? It is a foil-backed product on both sides which is supposed to include both a radiant barrier and vapor barrier with an R-value of about 15. It is not supposed to hold any moisture.

Our Answer

According to the Prodex web site the only R value of 15+ is the roof insulation. The crawl space product using two layers will only provide 8.24 R value. A lot of money for the product and R value overall.

How large of an area are you wanting to insulate? is there heating or cooling ducts in this crawl space area? What about water pipes? The ideal way of insulating a crawl space is to air seal it and insulate the side walls while installing a heavy gage moisture barrier on the floor. Then seal up any ventilation vents. If there is access to interior basement, then open that up and bring the crawl space into the inside environment.