How to Insulate an Attic with Fiberglass

In this video, This Old House general contractor Tom Silva shows affordable ways to create an energy-efficient attic.

Steps for Insulating an Attic with Fiberglass

1. Cut fiberglass batts to fit tightly between floor joists.
2. Lay the fiberglass batt between the joists with the paper vapor barrier facing down toward the heated space. Lightly press the batt down between the joists. Note: When installing insulation along the eaves, be careful not to cover the soffit vents.
3. Use unfaced fiberglass batts to insulate over existing insulation.
4. Add a second layer of insulation by lying unfaced fiberglass batts perpendicular to the floor joists. Butt the batts tightly together for maximum efficiency.
5. To insulate under the attic floor, use a pump to blow in fiberglass loose-fill insulation.
6. Insert the hose under the floor and turn on the blower.
7. As the loose-fill insulation packs tightly into the space beneath the floor, it will slowly push out the hose. Turn off the blower when the void is completely filled.

Materials

• Work gloves
• Knee pads
• Dusk masks
• Safety goggles

Tools