DIY: Cellulose Insulation in Walls

If you’ve got an old home that’s drafty by the exterior walls, chances are those walls are hollow. Many old homes were built without insulation, or with insulation that has long since disintegrated into dust. It is possible to insulate those walls by blowing in loose cellulose insulation. It’s a big project, but not as big as having to rip off the walls, install regular insulation, and rebuild them.

Things You'll Need

• Electronic stud finder
• Pencil
• Insulation blower
• Drill with hole saw attachment (wider than the hose on the blower)
• Joint compound (plaster)
• Mesh drywall tape
• Drywall knife
• Sandpaper

Instructions

1. Pinpoint each stud in the wall, using the electronic stud finder. Mark each position with a pencil, putting the mark at the top of the wall.

2. Cut a hole in the space between each marked stud, using your drill and hole saw attachment. Put the hole about 8 inches from the ceiling. Set aside and save the cut-out pieces.

3. Load your blower with cellulose insulation. Thread the hose into the first hole and push it all the way to the bottom of the inside of the wall. Start the blower and begin filling the wall cavity between the two studs.

4. Fill the whole wall cavity with insulation, pulling the hose slowly up and back out of the hole as it fills. Stop when the hose is back at the top and you can see the insulation piling up inside the hole. Repeat for each hole.

5. Put one of your cut-out wall pieces into each hole, plugging them. Press mesh drywall tape over it. Use a drywall knife to spread joint compound on the surface, smoothing it out. Let the compound dry for four to six hours, sand it flat, and apply a second coat of compound.

6. Repeat for a third coat of compound. Sand it smooth. Repaint the wall.

Tips & Warnings

• Wear a dust mask when using the blower.

References

• Build it Solar: Blowing Cellulose Insulation Into Walls