In the closet of an upstairs bedroom, there is a door about 3/4 the size of a normal door that leads to an unheated attic space. It gets pretty chilly in that closet during the winter months, since the door is a simple hollow core wooden door that does very little to keep out the cold air in the attic.
I'd like to add some insulation to the attic-facing side of the door, but I wasn't sure if I needed a special insulated foam board or some other kind of insulation for the task. Would a general purpose foam board adhered to the door be the best way to keep the closet warm?
Best Answer
Rigid foam insulation will be the easiest to install, since you can simply screw it on. The blue or pink stuff should be fine, and they are easier to handle than Poly-Iso (yellow with a foil backing). You should pick up a pack of insulation washers, often sold for duct insulation, at your home center or on amazon. These are essentially large domed plastic washers, which flatten against the foam board, and provide a much stronger connection than a simple screw-head. Make sure you place your screws into the solid wood at the edges of the door too, so they don't pull out of the flimsy center.
You should really look at air infiltration first though. Make sure you run weatherstripping (either rubber gasket or foam strip) all around the opening. Make sure it latches snugly.
Even a heavily insulated door won't do much good if you have a 1/4-inch gap running around the frame.