How to Insulate Panels for a Homemade Sauna

Remove the paneling from the sauna walls and ceiling if it is already installed in place. You’ll need to unscrew the paneling or pry it free from the wall studs with a pry bar if nailed or glued into place.

Measure the height and width of the cavities between the wall studs. Each should be 15 inches wide if built to normal specifications, so 15-inch batting will do for insulation.

Cut a strip of batting to match the heights of the wall cavities using a utility knife. Place a layer of batting into each wall cavity, filling it completely.

Cover the walls with the aluminum foil vapor barrier. Make sure the shiny side of the barrier points toward the sauna’s interior. Staple the barrier to the wall studs, placing a staple every six inches to hold the barrier in place. Overlap adjacent barriers on the wall studs only, and send a staple through both overlapping pieces to hold them in place. You can cut the foil using a utility knife when needed.

Repeat the installation process with the ceiling, filling the joists with two layers of the barrier to increase its R rating. Cover the two layers of batting with the aluminum foil.

Replace the paneling over both the walls and ceiling, securing them into place using the same methods used originally.