Joe writes from Florence, Alabama: "Building new home. I sprayed 1-1/2 inch of foam in a 2x6 cavity and would like to add Owens R-13. Is this doable? Or would it be better to place a reflective foil in the cavity?"

Answer: Because Owens Corning does not make the product, I am not familiar with the properties of spray foam insulation. I recommend that you contact that product's manufacturer to find out if it can be used in conjunction with fiberglass insulation. The vapor retarder should go on the warm-in-winter side and the foam insulation may already provide that function. Reflective foil is also not a product made or distributed by Owens Corning.