How to Insulate an Addition

Contact your local building department to determine which regulations and codes apply to your addition. The best time to consult your local government is prior to beginning your project. Your building department can offer valuable advice regarding the optimal insulation factor, or R-factor, for your area.

Measure the distance between the studs in the exterior walls of your addition. Select batted insulation in a matching size. Insulation comes in standard widths that match the distance between most standard wall joists. Measure the distance between your ceiling joists and select the correct size of batted insulation for this area.

Cut a piece of insulation as long as the height of your wall using a utility knife and straightedge to create an even cut. Place the insulation in between the wall studs, keeping the paper side facing the room while folding the tabs along the edges of the paper along the edges of the studs. Staple the paper tabs in place, placing a staple about every six inches along the lengths of the studs. Repeat the process along all the studs to cover the entire exterior walls.

Continue working on your addition by completing the drywall and any necessary plumbing or electrical work. After installing the drywall on the ceiling, you are ready to insulate the attic area of your addition.

Go into your attic space and unroll the batted insulation into the spaces between the ceiling joists. Place the paper backing toward you while pressing gently to avoid compressing the material. Cut the insulation to fit the joist spaces using the utility knife and the straightedge. In very cold areas, lay another row of batted insulation along the top of the first row, running it perpendicular to the underlying insulation.