Radiant Or Spray Foam Roof

What is foam insulation.

Radiant or spray foam roof.

I typically spray enough foam 5 lb open cell to achieve r 38 in our roofs. A foil manufacturer suggested the foil on the inside of the truss leaving an air gap between the foam and the foil. The challenge with a spray foam enclosed attic roof is that you cannot typically have a radiant barrier because of the lack of a proper air gap. Spray foam applied to the underside of the roof deck has the potential to trap moisture caused by roof leaks potentially leading to rot and decay of the roof framing.

Spray foam insulation doesn t protect attic spaces from radiant heat but does protect them from convection and conduction. In the summer radiant heat is the biggest contributor to heated attic spaces so spray foam insulation may not be as effective in keeping attics cool. The radiant barrier acts as your first line of defense against radiant heat and the foam closed attic acts as the second line of defense against conductive heat flow. The shingles are connected to the roof deck and the deck is connected to foam.

Bill delamar i have wondered if spray foam installed directly on the sheathing will shorten the life of the roof covering if no baffling is provided. Some heat will still flow by conduction through the roof foam assembly. This means that radiant barrier sheathing keeps your home comfortably insulated against outside heat and saves energy your power utility bills up to 17. Another alternative to radiant barrier foil are the various types of foam insulation.

Foam insulation rigid boards are 4 x8 sheets usually cast of closed cell polystyrene designed to fit directly inside walls against the interior or exterior of plywood sheathing as. Foam insulation most commonly comes in two forms.