Air-Sealing and Insulating, Images 9-19

The sheathing is strapped on 2-foot centers, directly over the wall framing. The top of the venting channels is open to the soffit, ensuring positive airflow from the bottom up.

Ridgevent material blocks the gaps between strapping, forcing an insect barrier screen against the back of the siding.

The fiber-cement siding was custom- ripped to allow narrower courses and tighter stacking at the base of the wall.

Foam-board vent baffles prevent wind-washing of the cellulose insulation in the attic ceiling areas.

A 3-inch layer of spray foam effectively air-seals the vent baffles against the framing and insulates the rim joists to about R-18.

Sloped ceiling rafter bays were fully baffled with 2-inch foam board, then filled with closed-cell foam.

Note the insulated rim joist and squash blocks below the single top plate. A layer of 2-inch R-13 foam board completes the sloped ceiling insulation, yielding a total approximate R-value of 70.

Complex framing areas are ideal spray-foam candidates.

At roughly R-6 per inch, the 2x8 framing bays approach a nominal R-44. Two doghouse dormers were also insulated with closed-cell foam.

The finished basement walls were insulated to R-25 with a combination of 2-inch XPS foam and R-15 fiberglass batts.

Note the air-sealing tape over the seams. Spray foam on the rim joist laps onto the XPS on the foundation walls, creating an air seal along the top of the board.

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