Your attic is insulated, but you’re still losing a lot of heat from the attic space. In this case, try replacing the insulation and blocking holes to control drafts. In most cases, you can use fiberglass insulation, which will ensure that this project remains relatively inexpensive. Of course, over time you should recoup the cost of the insulation materials through your lowered utility bills.
Step 1: Remove the existing insulation. If you have loose insulation, simply wear a face mask and gloves and remove the insulation and stuff it into garbage bags. For blanket or batt insulation, you may have to remove the fasteners that attaches it to the joists.
Step 2: Caulk around any holes in the attic made for electrical wires. Patch any larger holes that are not purposeful for ventilation.
Step 3: Choose a faced insulation, like fiberglass batt insulation to insulate between the joists. Pick an insulation that is the exact width of the space between the joists, and is thick enough to fill the depth of the joists.
Step 4: Unroll the fiberglass insulation so it fits in between the joists. Staple the paper backing to the top of the joists, spacing the staples 8 to 12 inches apart. When working on the joists, you can use a piece of plywood to place over the joists. This will ensure that you won’t crush the insulation, or accidentally damage the ceiling.
TIP: While installing insulation, be sure to wear long sleeves, long pants, a face mask, gloves, and eye protection. This will prevent you from damaging your lungs or skin while working with insulation.
Step 5: Continue filling the spaces between the joists with fiberglass batts. Butt the ends of the fiberglass batts together to fill the space.
Step 6: Fill the roof supports with fiberglass batts as well. Make sure when installing the fiberglass batts that you don’t cover any of the attic vents or the baffles. Completely sealing the attic without allowing for ventilation will trap moisture in the air and may cause mold or mildew.