Spray Foam For Your Attic Spaces

There are two common ways to insulate your attic space and protect your home from other weather and moisture related damages using spray polyurethane foam.
Building Science (The Traditional Way)
Attic Floor Spray Foam Insulation Application (Through a Vented Attic)

Building science and design principles that your builder/architect subscribes to can often dictate the method of spray foam used in the attic. Insulation is used on the attic floor to insulate the ceiling from the seasonal cold and/or heat in a traditional vented attic setting. Between the floor joists, where cellulose and fiberglass insulation is traditionally used, spray foam is also applied. However, no insulation is applied to the rest of the attic. The attic, via soffit, ridge, and gable vents, remains highly vented. Although it is not the most effective system, it is the most common engineered system used throughout the U.S.
This is considered the most effective application by members of the spray foam industry because it effectively seals off and insulates the entire attic space from any air infiltration. The air barrier is created by applying foam directly in between the joists, on the gable wall ends, and down around the rim and into the soffits of the underside of the roof.

The traditional practice of to work in that type of severe conditions. There is also opportunity for moisture to form due to condensation on these appliances.
To achieve insulation of the attic space from the extreme heat that radiates through the roof, the sheathing, and the singles, spray foam needs to be applied directly to the underside of the roof deck. This provides the attic with the type of insulation that blocks out severe temperatures. The attic then becomes as comfortable as any other room in the house, since it is now a “conditioned” space. It is argued that this system can cause the shingles on your roof to overheat and curl off. According to designers and builders, the reason for this happening is because wood needs to breathe.