SAB HOMES 7 - Captain Kidd’s Terrace
LEED Platinum house uses existing foundation and salvaged materials
This low-cost, 1,190sf, LEED Platinum house is sited on an existing 20-year-old foundation on pedestrian-oriented Protection Island, a five minute passenger ferry ride from Downtown Nanaimo.
By Dr Nancy Mackin
The rectangular floor plan, shed roof, wood technologies, and palette of regional materials recall the plank houses built for millennia by the indigenous peoples of south-coastal British Columbia.
Recycled and salvaged materials predominate, with the remainder of materials sourced regionally whenever possible. Cost savings from the recycling left enough room in the budget for technologies such as a grey water collection system, a hybrid hot-water tank that borrows heat from the surrounding air, highly efficient programmable heating systems, and dimmable LED lighting.
Because the building utilizes a foundation that had existed on the site for 20 years, all existing trees and 95% of groundcover vegetation were retained. The house was built without the use of large machinery, further minimizing disruption of existing plants, soil, and site hydrology. This woodland retention, which links to “Pirate’s Park”, adds resilience to the natural ecosystem, adding habitat for wildlife within the delicate island biogeography.
The narrow footprint enables daylight and fresh air to reach all spaces, all of which are within seven metres of an operable window. The double-height living/ kitchen/ dining space share a mini-split heat pump powered by clean hydro-electric power. [Solar power was not an option given the number of trees on the wooded, shady site, and wind power was rejected because of the abundant bird population.]
The house uses 75% less water than a reference three-bathroom house, largely due to the lack of turf grass and the established all-native planting, which enable the landscape to survive dry summers using only captured rainwater for irrigation. The shed roof slopes to the east [uphill] side of the site, and water is collected in a tank, to be gravity fed to the rest of the site when required.
These measures, together with the use of water-efficient dual flush toilets, greywater collection for toilet flushing, and a water-efficient clothes washer reduce potable water consumption per occupant to 20 gallons per month.
Energy conservation begins with the building envelope which is designed to have the minimum possible interior joints – even the stair is freestanding to ensure an uninterrupted air barrier. Despite its simple form, the house employs advanced systems for conserving energy and water. A highly efficient mini-split heat pump provides affordable comfort for the main living spaces. The bedrooms each have a ceiling-mounted radiant heater that makes spaces feel several degrees warmer than they are: more comfort for less energy. Occupants monitor seven programmable thermostats to ensure heat is not wasted.
The hybrid hot water tank uses heat pump technology, borrowing heat from surrounding spaces. The annual electrical consumption is about 90% better than that of an average three bedroom, three bathroom house, with the cost of energy being about $25 per month in the winter.
To minimize resource depletion, the owners/ architect salvaged materials before and throughout construction. Eight salvaged doors were transported to the site by a small barge; discontinued carpet tile samples were donated and the architect arranged them like a patchwork quilt; while kitchen cabinets and sink were salvaged from a demolition site. All wood floors [maple and tamarack] were repurposed. House numbers, window coverings, and furnishings were salvaged. 90% of new materials by value were regionally produced. All paints and adhesives were non-VOC for occupant health and comfort. 90% of waste materials were recycled during construction.
Through its combination of efficient design, simple form, attention to detail, use of salvaged materials and judicious application of energy and water saving technologies, this project demonstrates that LEED Platinum performance can be achieved even on a modest budget.
Dr Nancy Mackin MAIBC, MRAIC PhD LEED AP is principal of Nancy Mackin Architecture in West Vancouver.
