Koshoshiki Passive House on Stilts

Location: Squamish-Lillooet Regional District, British Columbia
Building Type: Single Family Residential
Project Phase: Under Construction
Certification Type: PHI Low-Energy Building
Year of Construction: 2020
Gross Floor Area (m2): 4,249
PHPP Verification: Download
Certified Passive House

PHI Low-Energy Building


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Project Description

‘Kōshōshiki no ie”, 高床式の家in Japanese, roughly translates to “Stilt House”. The name acknowledges the central role that stilts play in the project’s overall concept. Koshoshiki Passive House on Stilts is a minimalist custom home built on pilotis, designed to take advantage of the natural views while reducing its environmental impact on the surroundings.

This project aims to understand its beautiful location in the bend of a stream, nestled between mountain ridges north of Pemberton. The architecture embraces the spirit of the West Coast with a smart and simple design that fortifies a connection to nature. The raised deck creates an outdoor space for occupants to safely flow from inside to out, without disturbing local bears and other fauna who are free to stroll beneath the structure. By lifting the house out of the ground, it is also raised out of the shadows. Large floor to ceiling windows provide excellent views while maximizing solar access for passive heating.

The decision to build Koshoshiki Passive House on stilts was driven by several ecologically inspired reasons. Firstly, a desire to reduce concrete and therefore CO2 emissions. Similarly, it eliminated the need to use fossil fuel based, non-biodegradable insulation materials like rigid foam insulation, as the wood floor is insulated with rock wool and cellulose. It also aligned well with the challenges of building on an uneven and remote terrain. Creating a structural steel grid on which to sit the house, allowed for floors, as well as the walls, and roof to be prefabricated off-site. This minimized the need for equipment on site and disruption to the surrounding ecosystem. The stilts quite literally reduce the house’s footprint, while maintaining topsoil and keeping native plant species intact, reducing disruption to groundwater, preserving infiltration on site and lowering the amount of water runoff to the creek.

The site has limited solar access due to shading from surrounding mountains. The house also has a large form factor, ironically due to its small overall size of only 1400SF. Both issues posed challenges for Passive House certification. Thanks to our dedicated team and motivated clients, Koshoshiki Passive House on Stilts meets the PHI Low Energy Building Standard.