Wii Gyemsiga Siwilaawksat Student Building

Award of Excellence

Morrison Hershfield

The Wii Gyemsiga Siwilaawksat Student Building at Coast Mountain College in Terrace, B.C., integrates light wood-framed modular housing units with a site-built mass-timber central atrium. Morrison Hershfield’s (MH’s) energy modelling and airtightness testing resulted in a high-performing building envelope that contributes significantly to the residence being net-zero ready. It exceeds the minimum threshold of the BC Energy Step Code 4 energy-efficiency requirements in a particularly cold, northern coastal climate (Zone 6).

An integrated process The three-storey, 230,000-sf building replaces four aging student housing buildings. It features a cultural space, 108 student rooms, two visitor suites, an elder suite, two shared kitchens, two collaboration areas, a computer lab, an esports room, two shared kitchens and bike storage.

The college selected a design-build team to deliver the volumetric modular and mass-timber hybrid student building in a fast-tracked 17-month schedule. The prime consultant, HCMA Architecture + Design, retained MH.

The performance of the building envelope was verified by a blower door test conducted in compliance with ASTM E779, Standard Test Method for Determining Air Leakage Rate by Fan Pressurizatio. The final building envelope airtightness was measured at 0.25 L/s/m2 @ 75 Pa.

By integrating MH’s energy consulting with façade-envelope design, a larger variety of options for achieving (and exceeding) the energy-performance threshold were available.

Factory-built and site-built The project involved site-built hybrid structures and volumetric modulars with wood framing and metal-skinned structurally insulated panels (SIPs) for the floors and roofs. Air, vapour and moisture control detailing improvements were needed to integrate the SIPs with the conventional envelope system and co-ordinate various high-performance assemblies, to reduce thermal bridging between the site-built and factory-built construction.

Thermal component modelling was undertaken to determine assembly performance and overall thermal bridging impact for compliance with the energy model. The building envelope of the volumetric modulars was partially completed in a factory in Edmonton, then tied-in to the site-built steel and mass timber hybrid atrium structure and finished on-site.

The cladding design repeats custom metal brake-shape profiles a pattern to form a closed-joint rainscreen system. Fabrication, sequencing and flashing details were developed on-site.

An unconventional, site-specific foundation was constructed as an above-grade insulated void system for the residential-wing volumetric modulars and

aligned to a raised slab on compacted fill for the central atrium area. Early co-ordination enabled a rapid start for volumetric modular manufacturing, which overlapped with on-site foundation construction.

Reducing emissions The project featured many energy-saving and environmental measures, including the following: • a high-performance envelope with triple-glazed windows. • exterior wall thermal bridging reductions and efficient detailing (R-22.5 effective). • a minimum R-40 roof. • in-suite electric baseboards to reduce the greenhouse gas (GHG) emissions of natural gas. • ventilation air heat recovery in suites and the atrium. • natural and energy-efficient lighting. Also, wood is a natural, renewable and sustainable construction material. The building combines wood-framed volumetric modulars and heavy timber to satisfy the BC Wood First Act.

Rapid construction The design-build process was successfully delivered within a tight schedule using non-traditional construction. Air barrier terminations were pre-stripped in the modular manufacturing factory and tied-in on-site. The atrium building and the entire shared foundation were constructed onsite before the modular components arrived. The residential corridors and stair cores were infilled afterwards.

The site-specific foundation design enabled a rapid start to the construction, avoiding winter delays and fast-tracking approvals for the start of modular manufacturing. Once construction was completed, Wii Gyemsiga Siwilaawksat was able to welcome students in January 2022.

Wii Gyemsiga Siwilaawksat Student Building, Terrace, B.C. Award-winning firm (building envelope and energy modelling consultant): Morrison Hershfield, Burnaby, B.C. (Brett Pattrick, P.Eng.; Eric Wood; Voytek Gretka, P.Eng.; Stephen Wong, EIT). Owner: Coast Mountain College. Other key players: HCMA Architecture (prime consultant, architect), IDL Projects Inc. (design-build contractor), MODUS Structures (modular manufacturer), McAuley Architectural Consulting (code consultant), Scouten Engineering (structural), Interior Mechanical Consultants (mechanical), NRS Engineering (electrical), L&M Engineering (civil), GeoNorth Engineering (geotechnical), A&J Roofing (supplier), Competition Glass (supplier), Acadia Mechanical (supplier), Bryant Electric (supplier).

ENGAGING with our clients and communities helps us understand their sustainability goals, so we can provide balanced and resilient solutions.

morrisonhershfield.com