Radiant Or Spray Foam Roof

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.

Radiant or spray foam roof.

Foam insulation most commonly comes in two forms. Spray foam insulation radiant barrier sheathing radiant barrier sheathing can reflect back up to 95 of the heat absorbed and can consequently reduce attic temperatures by up to 20 degrees f. 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. 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.

This means that radiant barrier sheathing keeps your home comfortably insulated against outside heat and saves energy your power utility bills up to 17. Spray foam insulation doesn t protect attic spaces from radiant heat but does protect them from convection and conduction. What is foam insulation. The shingles are connected to the roof deck and the deck is connected to foam.

These issues may go unnoticed for years until it s too late. 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 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. All manufacturers of radiant barrier sheathing say not to spray against their product it will render it useless.

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. I typically spray enough foam 5 lb open cell to achieve r 38 in our roofs.