How to Insulate an Old Stone Basement

Seal the area between joists where the mudsill meets the foundation with an expanding foam insulation.

Measure the height of the basement walls and determine the approximate middle of the walls by dividing the height by 2.

Snap three horizontal chalk lines along the walls: one at the top, one just 1/2 inch above the floor and one through the middle.

Install three bands of 2-by-2-inch horizontal furring strips along the walls, conforming to the chalk lines you snapped in Step 3. Use a masonry drill with a carbide drill bit to drill pilot holes through the furring strips and into the stone. Have a couple helpers hold the furring strips in position while you insert masonry screws through the pilot holes. You should also install furring strips along the edges of windows.

Unroll blanket insulation and use a utility knife to cut it 1 1/2 inches longer than the space between the top furring strip and the middle furring strip. Staple the insulation to the top furring strip. Staples should be placed four inches apart. When the top of the insulation has been stapled to the top furring strip, staple the bottom of the insulation to the middle furring strip. Continue this process all the way around the basement. Insulation should be cut to fit around windows, and stapled to the furring strip around the windows.

Cut insulation to fit between the middle furring strip and the bottom furring strip, and staple the insulation to the furring strips as you did in Step 5.