TarsemHaus Townhouses

TarsemHaus, an eight-unit townhouse development, makes a striking ecological statement from its Passive House goals to its clustered design that enhances social connection and small-community character.

Squamish, a former logging town in coastal British Columbia, has seen rapid growth in the last few years due to its proximity to Vancouver and countless outdoor activities on its doorstep. As the first proposed certified Passive House development in the area, TarsemHaus provides a promising precedent of quality design, while achieving calculated high levels of energy efficiency.

The 1,570-m2 trapezoid-shaped lot was extensively studied to create a unique layout and maximize usability, according to Derek Venter, principal of Derek Venter Architectural Design, Incorporated. The result was eight spacious townhouses averaging 150 square metres that form a horseshoe around a prominent landscaped central courtyard. The courtyard is easily accessed from each unit, promoting safe and inviting spaces for children to play and neighbours to interact, while a central stair invites the public into the courtyard. The development provides ample outdoor space for residents; in addition to the courtyard, each townhouse has a private rooftop deck, capturing the remarkable views of the surrounding mountains.

As the Passive House certification goal for this project was a first for Squamish, the project was confronted by all the related firsts associated with a development of this nature. While the municipality and community have supported the project, the learning curve for many involved parties has been a challenge. The unwavering determination of the developer, LTO Developments, Incorporated, to ensure that Passive House standards would be met was largely what made this project possible. The high level of liveability, neighbourhood amenity, and architectural expression—along with the pursuit of the Passive House standard—helped the developer to sell most of the units before they were completed and led to the project winning the Design of the Year for 2018 award in the Residential category by the District of Squamish Advisory Design Panel.

The project’s complexity was compounded by the fact that the lot is situated in a floodplain, making it necessary for the living spaces to be elevated. For this reason the ground floor contains only the garages and additional storage space. The thermal envelope of the building begins at the second storey, with most of the mechanical equipment located within the units. To maximize the floor area within the units, the sprinkler system and some electrical equipment are situated in a ground-level mechanical room that utilizes a watertight submarine door to eliminate any potential damage caused by flooding.

Set over the unconditioned garages at the second storey sits a 46-cm TJI floor filled with dense-packed glass wool insulation for a total R-value of 73. The plumbing and all other services are run through this assembly, eliminating freezing concerns. An air barrier membrane wraps from the bottom of this assembly up to the walls to form a continuous airtight layer.

The exterior wall assembly achieves an R-value of 68 with 2 x 6 framing and a 30-cm TJI installed vertically on the exterior, both filled with glass wool insulation. The insulation on the interior side of the air barrier was specifically chosen for its greater health benefits to the occupants. An air barrier membrane covers the TJIs and is encased by two layers of 1 x 4 treated strapping set at opposing 45° angles to form a rain screen gap. This allows both vertical and horizontal ventilation and accommodates siding materials set at different orientations. Fibre cement panels, corrugated and standing-seam aluminum, and cedar panelling make up the external layer montage, visually differentiating and clearly identifying each unit from the streetscape.

The total roof assembly consists of insulated 41-cm TJIs together with a 2 x 8 overframing layer insulated with an additional 14 cm of mineral wool above the TJI layer. The 2 x 8 layer supports a two-layer torch-on membrane, creating a durable roof assembly with an impressive R-value of 84.

The outstanding R-values reached in the external assemblies allow the mechanical equipment to be as simple as possible. The project boasts the latest generation in ERVs to efficiently ventilate the spacious homes, each of which contains three bathrooms. Heating within each townhome is provided through in-line duct heaters connected to the ERV units, and in-floor electric heating provides additional comfort in bathrooms. The building is cooled in summer through passive cross-ventilation strategies implemented by the residents, which are explained in a detailed user manual supplied with each home. In keeping with the sustainable ethos of the project, all the homes feature electrically powered appliances and equipment, including induction cooktops, ventless condensing dryers, and LED lighting.

The architectural and development team state that their ambition for TarsemHaus is first and foremost that it be a home for families to make memories in and build lasting relationships with their neighbours in a healthy and sustainable environment—and that this experience instills a culture of environmental consciousness in all.