A customer was having significant problems with their roof. Ice dams were forming in the winter, and there was also signifiant condensation issues. A home produces a lot of moisture which finds its way into the attic. The attic was poorly insulated which caused problems as the warm moist air from the house collided with the cold air of the outside environment. This resulted in condensation and other significant issues. Additionally, the exhaust vents in the home were done incorrectly causing more problems.
There was no way to get a satisfactory result using typical insulation practices, and it was determined that the best option would be to do a closed envelope insulation where the attic was completely sealed from outside air. We used a combination of closed and open cell foam insulation. The first two inches were closed cell and the rest was open cell. This yielded an excellent R insulation value, and will prevent future moisture and ice dam problems. Note that foam insulation must be done correctly, otherwise the foam will not cure and off gas toxic fumes. When done correctly, this type of insulation is the best option for this type of application. Its only downside is that it is more expensive.
