How to Finish Basement Walls With Insulation

Lead Image
  • 10-30 hours
  • Intermediate
  • 2,000-8,000
What You'll Need
Spray foam
Plastic sheet
Moisture proof paint (or moisture barrier)
Measuring tape
Utility knife
Chalk line
Permanent marker
Foam insulation adhesive

By finishing basement walls and applying insulation to them, you can convert an unfinished basement into a comfortable place for you and your family or guests to spend leisure time. Follow these instructions to transform your uncomfortable basement into a pleasant setting in just a few easy steps.

Step 1 - Seal Gaps in Exterior Walls

To keep outside air from entering your finished basement, inspect all exterior walls for gaps and open spaces through which pipes and cables enter your basement. Fill these gaps with enough spray foam that outside air will not penetrate them.

Step 2 - Seal Basement the Walls Against Moisture Intrusion

Before applying insulation, you'll need to test for moisture intrusion. Tape a small sheet of clear plastic to your exterior wall and leave it for a day or two. If you find moisture beads on the inside surface of the plastic, then moisture is entering your basement through its exterior walls. To prevent this intrusion, cover your exterior walls with a waterproofing, waterproof paint, or a moisture barrier.

Step 3 - Seal Basement Wall Against Water Seepage

If you find that water is leaking through your basement wall, you can be sure that it is coming from outside. This water can come from downspouts emptying too close to your basement wall or from soil that has not been landscaped to slope away from the house. Try remedying these problems by making the required changes. If you're unable to do that, at least install a sump pump in your basement to remove pools of water.

Step 4 - Buying Insulation

Determine the R Factor you'll need and measure the surface areas of walls you'll be covering with insulation. Since you'll be installing insulation in open walls, you'll want the rigid board type.

Step 5 - Cutting and Fitting

Cut the rigid board insulation and attach the pieces into irregular and oddly shaped spaces where a rigid board will not fit. Measure the space into which you'll need to fit your insulation. Use a permanent marker and either a straightedge, or a chalk line to make lines on your insulation board. Use a utility knife to score the board, then snap the board so that it breaks at the score.

Step 6 - Gluing Your Insulation

On wall surfaces where you'll be fitting whole insulation boards or pieces that will be placed into irregular spaces, cut the tip from your insulation adhesive applicator so that it will lay a .25-inch bead. Apply it to the wall and press your insulation board in place. Purchase adhesive that is formulated to glue foam insulation. Avoid using conventional construction adhesive.

Step 7 - Caulk Seams and Gaps

When you are finished gluing all your rigid insulation boards and pieces, caulk the seams and gaps you find between the boards and pieces.