Insulating Your House from CMHC Series 7-10

Attic Insulation
The attic is often the most cost-effective place to add insulation. Usually, a contractor blows loose fill into and over the top of ceiling joists. For the do-it-yourselfer, batts laid sideways on existing insulation are an easy alternative.

• The air barrier at the ceiling line must be tight to ensure warm moist air from the house does not get into the cold attic and condense in the winter. Check ceiling light fixtures, the tops of interior walls and penetrations such as plumbing stacks for air leakage.
• Ensure that soffit venting is not blocked by added insulation; baffles may have to be installed.