Site Features: Energy Efficiency, Indoor Air Quality, Design, Solar Power, Advanced Building Envelope
Madrona Passive House, a new home designed by SHED Architecture & Design and under construction by Hammer & Hand, combines contemporary design with high performance building to create an environmentally responsive and resource-efficient house for a family of four.
Built on a Seattle hillside with sweeping views of Lake Washington and the Cascade Mountains, the project illustrates the flexibility of Passive House to deliver super-efficient buildings to sites with challenging topographic and environmental conditions. To negotiate the site’s environmentally critical steep slope, a structural slab supported by 26 piles drilled deep into the hillside effectively “floats” the house above marginal soils on a “platform-on-stilts.”
Structural foam insulation lines retaining walls and the structural slab to eliminate thermal bridging. Exterior walls employ high-density cellulose insulation, ZIP sheathing, mineral wool, and a rainscreen of vertical cedar siding. The roof features high-density cellulose, tapered foam and a thermally isolated stanchion for the project’s 10kW solar PV array, sized to offset much of the home’s energy demand. Exterior mechanical blinds on the home’s triple pane windows modulate solar gain to avoid over-heating. A green roof and rainwater harvesting reduce stormwater run-off. Planning for the future, the 3764sf home will divide into a 2964sf main house and 800sf ADU when kids go to college.
By investing in sustainable site development strategies, efficient building systems and an advanced envelope, the project aims to respect the home’s environmentally critical site and achieve one of the world’s most demanding building energy standards: Passive House.