How to Retrofit Insulation in Residential Walls

Cellulose insulation is made from recycled newspapers.

Adequate insulation in your home's walls and ceiling can go a long way towards reducing your utility bills. With new construction it is easy to get proper insulation installed, but to retrofit insulation is a little more involved.

Things You'll Need

• Cellulose insulation
• Cellulose insulation blower
• Drill with 1 1/8 inch hole bit
• Ladder(s)
• A helper or two

Instructions

1. Drill a 1 1/8-inch hole between the studs in an outside wall at the bottom and top of the wall. This can be done either from the interior or exterior of the home. Depending on the siding, the exterior wall may be easier to patch, or the inside might supply easier access.

2. Load a bag of the cellulose insulation into the blower in preparation for blowing it into the wall.

3. Place the nozzle of the hose attached to the blower into the bottom hole and turn on the blower. Insulation should begin to flow into the wall cavity.

4. If insulation begins to blow out the top hole, plug it with a rag. If no insulation blows out, there may be a horizontal block in the wall keeping the insulation from making it to the top hole.

5. When the blower begins to whine, switch the nozzle to the top hole. Fill this hole until the blower again begins to whine. The wall cavity should now be insulated.

6. Turn off the blower and remove nozzle from the hole.

7. Repeat this process between all the studs on the outside wall. Above and below windows and doors will require some additional holes, but these are important areas to insulate.

8. Patch all the holes.

Tips & Warnings

• Read all the directions with the insulation blower before using it.

References

• This Old House: How to Retrofit Cellulose Insulation