Exterior Wall Cavities

Winnipeg spray foam and roof

If your house was built before 1930, chances are that the exterior walls are empty. If so, your walls can be drilled (usually from the outside) and filled with dense-pack cellulose insulation to R-14 (R-3.7 per inch). Dense-pack cellulose greatly reduces drafts in walls, especially compared to fiberglass batts, and provides excellent sound-proofing and fire-retardancy.

Post-war houses usually have a minimal amount of insulation in the walls (usually R-8 mineral wool batts). Therefore, these are not the best candidates to achieve a uniform distribution of cellulose with the dense-packing method. Furthermore, it is usually not considered practical or cost-effective to open up such walls unless the plaster or siding needs to be replaced. Other options can be considered on a case-by-case basis.

Dense-packing cellulose into the empty walls of a Wolseley house built in 1883
Dense-packing cellulose into the empty walls of a Wolseley house built in 1883

 

Carefully removing cedar shakes to drill holes into the empty wall cavities behind
Carefully removing cedar shakes to drill holes into the empty wall cavities behind

 

Injecting cellulose into the wall while plugging a different hole in the same cavity
Injecting cellulose into the wall while plugging a different hole in the same cavity