Air Sealing and Insulation Contractor Alert
This is a Seattle City Light BUILT SMART project and the following requirements must be met when constructing a BUILT SMART building in the Seattle City Light service area.
For a detailed explanation of program requirements, refer to the BUILT SMART Technical Specifications provided to the General Contractor.
Air Sealing Requirements
All penetrations through the building envelope shall be sealed with appropriate material (caulking, insulating foam, mineral wool, backer rod, etc.) to limit air-leakage, including:
- Around glazing and doorframes, between the unit and interior Sheetrock or rough framing.
- At any exterior penetrations in the rim joist framing, (especially around all blocking where the floor joists are cantilevered to support an exterior deck).
- At the bottom of the wall plate where it meets the slab floor.
- Around any penetrations in the building envelope for ducts, through-the-wall air inlet vents, and access hatches.
- Around all outlet, switch, or other electrical boxes in the exterior walls, ceilings, or floors (foam gaskets under finish cover plates meet this requirement).
- All recessed fixtures (e.g., wall heaters, exhaust fans, medicine cabinets, recessed lights, etc.) shall be sealed to the component assembly in all walls and ceilings.
Seattle City Light BUILT SMART Inspectors will thoroughly inspect the quality of all insulation applications, including the following areas:
- Perimeter slab on grade insulation must be R-15.
- Exhaust ducts in unheated spaces shall be insulated to R-4.
- Insulation must be cut to fit cavity. No voids or compression are allowed.
- All framing cavities in exterior wall must be fully insulated (no voids).
- All headers must be fully insulated to capacity of cavity.
- Split or cut batts around all plumbing and wiring.
- All rim joists between floors shall be insulated to the above-grade wall R-value.
- Insulation shall be installed in a permanent manner and include the required vapor barrier.
- All fan and recessed light housing on the top floor only must be fully insulated above.
- Vapor barrier required on all exterior walls and exterior ceilings.
- All interior stairwell and elevator shaft walls adjacent to any residential unit, or any other conditioned residential space shall be insulated to a minimum of R-19.
- All concrete walls above and below grade must be insulated to a minimum of R-21.
A BUILT SMART inspector must conduct the following inspections:
- All slab-on-grade insulation prior to concrete pour.
- All caulking prior to covering with insulation.
- All insulation and vapor barrier(s) prior to covering with wallboard.
- All outside exterior wall insulation prior to covering with exterior finish.
For more information, call Peter Held, BUILT SMART Program Coordinator, at 206.684.3605.