Insulation and Ventilation: Insulating Walls

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Insulation is an important investment to reduce your energy bills, and exterior walls are the first place many people look for improving insulation. It’s easiest to insulate during construction, while the stud walls are exposed, but insulation can be blown into stud bays. If you have the chance, make sure you have a vapor barrier in your exterior walls. In colder climates, the barrier should be placed on the warm-in-winter side of the insulation. Only interior walls tend to be insulated for soundproofing (more info on this page), but thermal insulation can be applied if required using the technique shown here.

Insulating A Finished Wall With Loose Fill

A. Drill a hole into the wall, near the floor, for the insulation blower to fit inside.

B. Insert a measure to check that the bay is empty. If you find obstructions that are not electrical, drill a new hole above the obstruction.

C. Fill the blower’s bin with loose-fill insulation.

D. Push the blower’s tube into the wall and begin to blow the insulation into the wall.

E. When all of the bays in the wall are filled, patch the hole in the wall.

F. Reapply a building material and the exterior sheathing material to the wall.

Insulating A Wall With Rigid Foam Insulation

A. Measure the insulation board to fit between the studs.

B. Cut the board to length with a handsaw.

C. Place the insulation board inside the stud bay.

D. Tape or glue the board in place. Screw drywall panels in place over the insulation board.

Insulating A Wall With Blanket Insulation

A. Measure the height of the stud bay where you will be placing the insulation and transfer this measurement to the insulation.

B. On a plywood surface cut the insulation to size using a utility knife and metal straight edge.

C. Place insulation in the stud bay, vapor barrier facing the warm side of the wall. In the north, that’s inside. In the south, that’s outside.

D. Staple the flaps of the insulation to the studs.

Next: Insulating Floors

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