Spray foam is used in attics, ceilings, walls, and floors. When applied, it expands to 100 times its volume to seal cracks and crevices. It also maintains some flexibility as the home ages.

This is also why I never use fibre insulation in vaulted ceilings in my own projects. Spray foam is a much better option because it acts as its own impervious air barrier. Applying it would have ...