Finishing Basement Walls with Insulation

By finishing basement walls and applying insulation to them, you can convert an unfinished basement into a comfortable place for you and your family to spend their leisure time. If this is your first experience with this kind of construction, refer to the information below for instructions and a list of needed materials and tools.

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 be able to enter through them.

Step 2 – Seal Basement Wall 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. In finding moisture beads on the inside surface of the plastic, you'll know moisture is entering your basement through its exterior walls. To prevent this intrusion, cover your exterior walls with a waterproofing, waterproof paint, or install a moisture barrier.

Step 2 – Seal Basement Wall Against Water Seepage

In finding water leaking through your basement wall, you can be sure there is water leaking in from outside the exterior wall. 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 your house. Try remedying these problems by making required changes. If you're unable to do this, at least install a sump pump in your basement to remove water that pools.

Step 3 – Buying Insulation

In buying insulation to install in your walls, 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 4 – Cutting and Fitting

If you'll be installing rigid board insulation, you need to cut and attach pieces into irregular and oddly shaped spaces where a rigid board will not fit. First, measure the space into which you'll need to fit your insulation. Use a permanent marker and 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 it breaks at the score.

Step 5 – 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 off your insulation adhesive applicator so that it will lay a quarter-inch bead. Then, apply this to the wall and press your insulation board in place. In buying your adhesive, be sure you choose one that is formulated to glue foam insulation. Avoid using conventional construction adhesive.

Step 6 – Caulk Seams and Gaps

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