3. Insulation and air infiltration sealing

From the exterior the framing was sealed to the foundation with a foam pad. The sheathing on the outside of the house was taped and then 1.5" of foam insulation was attached to the sheathing and taped. This was all sealed further with house wrap to decrease air infiltration and to decrease the thermal transfer through the studs. From the interior all the gaps in the framing were sealed with calk. Then spray foam insulation was used to seal all the outside wall perforations any other possible places for air leaks and to seal and insulate the roof deck. Roof deck perforations were kept to a minimum to decrease leakage of conditioned air outward and water penetration inward. Blower door tests were done a) at the end of framing with the spray foam sealing = 2.44, b) at the completion of drywall installation = 1.41, c) at the end of construction = The result was 974cfm @50pa or 1.35 ACH@50pa (Air Changes per Hour). This is an exceptionally tight measurement. The 2012 IRC has 3.0 ACH at 50pa as a maximum infiltration.

After this, cellulose insulation was applied and allowed to dry. Cellulose was used for the remainder of the insulation due to its recycled content, its lower cost, fire retardant factors, and increased R values in the walls with complete cavity fill versus foam.

The regular attic space as most people are familiar with does not exist.  The roof deck is insulated; therefore the space above the ceiling is usually within 10 degrees of the house temperature.  HVAC ducts can then be run in that space with a decrease in thermal loss.  It also makes better storage space if that is needed, but then the spray foam insulation will need a fireproofing paint or wall board covering it.