In this how-to video, This Old House general contractor Tom Silva explains how to retrofit cellulose insulation.
Steps for retrofitting cellulose insulation
- Locate two adjacent wall studs on an exterior wall.
- Use utility knife to remove a shingle from the bottom of the wall; be sure the shingle falls between the two studs.
- Use a 1 1/8-inch-diameter spade bit to drill a hole through the wall sheathing where the shingle was removed.
- Check for studs using a straightened wire coat hanger.
- Remove a shingle at the top of the wall and drill 1 1/8-inch-diameter hole into the stud bay.
- Fill hopper on the insulation blower with cellulose insulation.
- Force the nozzle on end of blower hose into the lower hole in wall.
- Turn on blower to force insulation up into space between the two studs.
- Use a rag to plug upper hole, if necessary, to prevent insulation from blowing out.
- Once you hear the blower motor start to strain, turn it off and move the nozzle to the top hole.
- Turn the blower back on and force insulation down into the wall.
- Once the stud bay is completely filled, turn off the blower.
- Apply silicone caulk around the holes in the wall, and along the top seam of the shingle.
- Nail the shingles back to their original spaces with 4d galvanized finishing nails.
- Measure over 16 inches from first set of holes to locate the next stud bay.
- Continue to drill holes and fill the stud bays with insulation.
Tools & Materials