The Intergenerational House is a prototype 3,000 sf energy-efficient residence inspired by multi-generational living in close yet separate quarters as can be found in Europe and Asia. The design provides a three-storey main house, lower suite and a laneway house on a typical 33’ x 122’ Vancouver building lot with space allocated as: two adults and two children in the main house, grandparents in the spacious, lower two-bedroom suite, and tenants in the small laneway home, which could possibly house the children in future.

By Kenneth Chooi and Stefan Levasseur

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Novel living concept wrapped in a passive design

Site, Light and Air
The outdoor open spaces are designed as shared outdoor rooms, featuring native and edible plants, and fruit trees. The site’s surface is a combination of permeable, crushed local recycled stone and eco-turf grass that requires less irrigation and allows water to infiltrate the surface to reduce surface run-off. The old practice of using rainwater barrels is an economical way to irrigate the gardens.

Two roof gardens on the main house provide additional living spaces.  The laneway house has a bright south-facing terrace, which promotes another area for container gardening.
Windows are strategically placed to maximize natural direct and reflected sunlight into every room. Location of the main living spaces allow south-facing sunlight to provide natural light and solar heat during overcast winter months.

Light-coloured surfaces reflect sunlight within the interior. LED lights with timers are rarely used in the daytime and provide energy-efficient night lighting. All of the occupied floor area has an operable window within 7m. Heat recovery ventilators [HRV] in both buildings provides fresh air changes.

Passive design measures
Passive design for heating and cooling has delivered highly energy-efficient housing, according to BC Hydro. The measures include the following:
– South-facing windows allow direct sunlight during colder months to contact exposed concrete floors [thermal mass units], supplementing the radiant floor heating.
– Roof overhangs on the south elevation block out the direct summer sun to avoid over-heating during the summer.
– Window openings are designed to allow south-east summer winds to cross ventilate all the floors including the laneway house and basement suite. The staircase allows warm air to rise to the third floor where opening windows allow stack effect cooling in the main house.
– Prefabricated framing of walls, floors and roofs reduce construction waste and minimize thermal bridging.
– The cool roof reduces heat island effect.
– Solar Thermal Panel provides hot water heating for domestic use. [Estimated 30% of energy consumed is from renewable resources.]
– In-floor radiant heat and on-demand hot water heating.
– Drain water heat-recovery system and on-demand hot water system.

FSC [Forest Stewardship Council] certified engineered wood floors and marmoleum tile flooring provide healthy, environmentally-friendly choices. The framing of the main house and laneway house was prefabricated into 99 panels, reducing framing waste to less than 3%, and the on-site erection took only four days, reducing construction time.
Designing the framing in a 3D CAD program allowed for better detailing of the structure, reduction in thermal bridging and better coordination with mechanical and electrical consultants. Computer cutting machines based on the CAD drawings cut all roof joists, ensuring better accuracy of tapered roof joists and sloped roof areas. About 10% of doors, energy star light fixtures and appliances were reused from the previous home on the site; and  50% of materials during demolition were sorted and mostly recycled thus reducing landfill.

MATERIALS

• – Insulated concrete forms by Logix, supplied and installed by Fab-Form; wood framing prefabricated off site with computer cutting machines, including 99 wall and floor panels; batt R-20 Insulation and R-50 spray insulation in the ceiling, low-VOC interior paint; metal siding and fibre cement lap siding.
• – Euroline 4600 series tilt and turn windows with low E glass, made of PVC which contains -no plasticizers or lead, and is recyclable.
• – Grohe Canada Eurphoria 110 Mono hand shower, 2726500E, delivers a maximum flow rate of 5.7 L/min using Grohe DreamSpray® technology, distributing even and consistent water flow to every nozzle, and Grohe SpeedClean™ anti-lime system for easy maintenance.
• – Solar hot water heating panels are Viessmann Vitosol 200t with SCU124 Monitoring.
• – Radiant floor heating is Uponor EP Radiant Manifolds with Uponor tubing supplied by a Viessmann Vitodens 100 condensing boiler.

PROJECT CREDITS

• Architect DSK Architecture
  General Contractor Econ Group Construction and Development
  Framing Contractor Cutmytimber
  Landscape Designers RUF Project
  Structural Engineer Bevan Pritchard Man Associates Ltd.
  Mechanical Contractor Terra Mechanical Ltd.
  Energy Consultants E3 Eco Group

Kenneth Chooi, Architect AIBC, MRAIC, LEED Green Associate, Principal of DSK Architecture; Stefan Levasseur, AT, B.EnDs