Radiant Or Spray Foam Roof

Foam insulation most commonly comes in two forms.

Radiant or spray foam roof.

All manufacturers of radiant barrier sheathing say not to spray against their product it will render it useless. Spray foam insulation doesn t protect attic spaces from radiant heat but does protect them from convection and conduction. 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. This means that radiant barrier sheathing keeps your home comfortably insulated against outside heat and saves energy your power utility bills up to 17.

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 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. 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. Another alternative to radiant barrier foil are the various types of foam insulation.

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. Some heat will still flow by conduction through the roof foam assembly. I typically spray enough foam 5 lb open cell to achieve r 38 in our roofs.

What is foam insulation. 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.