Neil Norris, certified Passive House Designer and senior member of Morrison Hershfield’s Façade Engineering group, gave an intensive Happy Hour talk on November 25 that focused on the construction details of the Artscape project. Located in Vancouver, British Columbia, Artscape is a seven story Passive House building that will host gallery space on the ground floor with art production spaces in the upper levels. It is cool, artsy, and geeky—and unsurprisingly the geeky envelope detailing took center stage.
Before we jump into these details, however, Norris did discuss some of the thinking that helped guide their decisions with respect to the building’s mechanicals. As the interior of the building is expected to be filled out by the artists who will occupy it, this means the projected internal heat gains should be fairly low. The same can be said of the need for active cooling measures, even if temperatures rise due to climate change. The team at Morrison Hirschfeld has modeled the building using future climate scenarios and the combination of external shading, operable windows, and the VRF system providing heating and cooling should be able to meet future comfort demands. A single centralized ERV will be used for ventilation.
And now on to the building envelope.
Norris showed the wall assembly and particularly the window installation details that are allowing this building to meet both non-combustible and Passive House requirements. He discussed the optimization of the wall assembly whose first iteration was a very thick wall that included 10 inches of exterior mineral wool insulation. By shifting the steel studs to the interior and spacing the exterior cladding attachments 32 inches on center, among other measures, his team was able to cut the mineral wool insulation depth to 8 inches.
But what really got the Happy Hour crowd’s attention was the depth of the team’s commitment and training that is allowing the detailing to be implemented. The project benefitted in this regard from having a long lead time: two years from its initiation to the start of construction. Lecor, the construction firm involved, received a private tradesperson training course, and Prudence Ferreira led preconstruction team trainings at the British Columbia Institute of Technology’s learning lab, which were deemed extremely helpful.
This mockup was also appreciated by many members of the design team. “Some people are tactile learners,” noted Morgan McDonald, Director of Operations at Lecor. Being able to see and touch a physical structure rather than just a representation on paper gives them the ability to better understand the technical elements of the design and, in some cases, may provide insights into improvements that can be applied to the final project.
In addition to the mockup at BCIT, a very large and thorough mockup of the wall and window assembly was built in the garage (or parking arcade for Canadians) at the start of construction. Although the mockup could not be used to test the airtightness of the final assembly, it was used to familiarize the construction crew with airtightness testing and the use of a smoke pencil to find leaky trouble spots. The use of a translucent air and vapor barrier (3015 by 3M) helped to also show tradespersons how certain penetrations can effect the integrity of the barrier and overall airtightness.
Last, but definitely not least, the crowd was wowed by the extremely impressive catalogue of thermal bridging details that Norris and a team at Morrison Hirschfeld have been analyzing and compiling, thanks to funding from BC Hydro.
Thank you, Bronwyn!
This 800-page catalogue has gone through several iterations and is available at:
The team is currently working on improving search functionality and will eventually release a digital encyclopedia of these and many more details that will be accessible at https://thermalenvelope.ca/catalogue/.
As Monte Paulsen from RDH Building Science pointed out, this guide has revolutionized the understanding of thermal bridging heat losses and how to optimize assembly details to minimize them—not to mention the work required to model them. Moreover, designers who are struggling to overcome an obstacle may be able to see the solutions that others have employed in similar scenarios. If you are given the opportunity to stand on the shoulders of giants, you should take it.