In this application the spray foam is applied directly to the underside of the roof. Because of the foams high per inch R-value as well as being an air barrier at 1 inch and a vapor barrier at 2 inches this method is also very popular in half story retrofits because of the 2x4 cathedral ceiling rafters. Cathedral ceilings can add an element of charm and grandeur to any home,
It is important to use the proper building techniques to manage moisture and energy performance issues. Condensation in the insulated cavity space can lead to wood rot and mould, which can compromise the durability of the roof, the efficiency of the home, and health of the homeowners. The bulk of moisture moving into any insulated cavity is driven primarily by moisture laden air from the interior of the house. The best practice for any cathedral ceiling is to create an airtight roof assembly.
We spray closed cell spray foam insulation to the underside of the roof deck and making sure that the thickness is adequate to meet minimum code requirements (R30 5 inches). This insures that moisture-laden interior air can no longer penetrate and condense on the underside of the roof sheathing. The same goals can be achieved by insulating from the exterior as seen in the videos.
