Spray foam Insulation is the more efficient thermal barrier to prevent heat transfer from Attic space towards the living space. The most used practice is applying the foam directly underneath the roof deck, between the joists, down to the exterior walls of the house, on the gable wall ends and sealing off the entire attic space.
The method used is called the “non-vented attic method”
With this method, the attic becomes conditioned space. The great advantage is that it reduces the high summer temperatures (more than 130 degrees) inside the attics where the duct system usually is located, which implies the reduction in the workload of your air conditioning system.
The SPF will provide better energy performance, comfort, and interior air quality.