Wall Assembly & Connection Detail Drawings

This is a forum discussion, not really applicable to most homeowners planning upgrades. A homeowner in central Texas designing and building a new house asked for feedback on his wall and roof assembly plan. His design uses a slab foundation with post-tension cables, 2x6 exterior walls filled with mineral wool (Rockwool) batt insulation, plywood sheathing sealed with a liquid-applied weather barrier, 2 inches of exterior mineral wool board insulation, furring strips, and fiber cement siding. For the roof, he planned zip sheathing (structural panels with a built-in weather barrier), asphalt shingles, and closed-cell spray foam insulation, with the wall sheathing wrapping up through the soffit to connect with the roof sheathing and form a continuous air barrier.

A building science expert who replied said the plan would work, but noted that wrapping the sheathing through the soffit would be awkward to build. Instead, he suggested adding blocking between the roof rafters and using the spray foam itself to seal the connection between the wall's top plate and the roof, which would also help the structure resist wind better. The expert also cautioned that turning a few construction details into a complete, buildable drawing set takes more than sketching connections — it requires accounting for plumbing, wiring, and ductwork, and confirming everything meets structural and safety codes, which is why architects and designers charge for that work.

For a homeowner, this exchange is a reminder that airtight construction details at wall-to-roof connections matter for a home's long-term performance, but getting them right on paper usually calls for professional design help.