Directions for Installing Insulation

Install fiberglass batt insulation in walls by pushing it firmly between the studs and stapling the paper flaps to the studs; batts are sized to fit between studs. Measure smaller openings and use a utility knife to trim batts, with a straight edge to make cuts straight. Cut batts to fit around electrical boxes, pipes or other elements; cut in half and push to fit between the back of the box or around the pipe to the wall. Notch the back of batts to fit over electrical and other cables so there is insulation behind them. Cut batts at the bottom of the wall 1/2-inch long and force tightly into the space.

Lay batts across joists in the ceiling, if there is existing blown-in insulation. If there is no attic insulation, put batts between joists and staple in place. Work around and under any heating/cooling ductwork or electrical conduit or water pipes. Don't cover can lights that come up through the ceiling; build small enclosures of plywood or hardware cloth to shield lights or exhaust fans. Make baffles of rigid foam insulation or heavy cardboard to keep soffit vents open.

Tape all seams and edges with special insulating tape, usually supplied by the makers of the fiberglass batts. Cover every place where batts abut wood studs or framing. Cut batts to fit tightly around all windows and doors and tape the edges. Use spray foam to fill door or window cavities too small to accommodate fiberglass; use carefully as it expands quickly. Cut off any excess with a utility knife after it dries. Let it dry before adding fiberglass batts.