How to Insulate Completed Basement Walls

Find and mark each stud in the closed basement wall, then mark the halfway point between each of the studs.

Put your hole-saw bit in the drill. Cut a hole midway between each of the studs, along the top of the wall. Save the circular cutouts.

Load the insulation blower with loose insulation. Feed the hose into one of the holes, threading it all the way to the bottom inside the wall.

Start the blower. Fill the space between the two studs with loose insulation, gradually withdrawing the hose as it fills.

Repeat the process for each hole, so the spaces between each pair of studs are filled.

Set one of the cutout wall circles that you set aside into one of the holes. Press self-stick drywall tape over the edges of it. Spread joint compound over the whole circle and tape with a drywall knife. Work it until it's smooth and flat.

Repeat the process for each hole, setting the wall circles into all of the holes and applying the plaster over them.

Allow the joint compound to set for six hours. Spread a second layer of compound over the first, keeping it flat and smooth. Let it dry. Spread on a third layer. Let it dry for 24 hours.

Sand the plaster smooth with your drywall sander. The wall is ready for repainting.