No Canadian architect since Moshe Safdie has risen to global prominence as fast as Vancouver’s Michael Green. He has become respected across the continent as the apostle of wood, a charismatic Moses bringing forth tablets of CLT, MTP and LSL as the carbon-sealing solutions to the crisis of climate change. His powerful 2013 TED talk Why We Should Build Wooden Skyscrapers has been viewed an astonishing 1,108,728 times — more views, without doubt, than those garnered by videos from all other Canadian architects combined.
When Green arrived in Vancouver in 1997 after studying at Cornell and working eight years for César Pelli, an advanced wood-design scene was emerging in the city, centered around architects Bing Thom, Peter Busby, Larry McFarland, Florian Maurer and the Patkaus; engineers Paul Fast, Gerry Epp, Robert Malczyk and Eric Karsh; and manufacturers StructureCraft of Delta and Structurlam of Penticton. While at MGB, Green became intrigued by the possibilities of mass timber high-rise construction — buildings of 20 storeys and more. In 2012 he coauthored the resulting report The Case for Tall Wood Buildings with engineer and frequent collaborator Eric Karsh of Equilibrium Consulting. With this, the lecture invitations poured in and his career took off.
And since Green’s status as an advocate of wood is secure, it is time to look at one of his firm’s key finished constructions, as this polemicist is also very much a builder.
Wood Innovation Design Centre, Prince George
Gathering together several wood-industry promotional organizations, plus the University of Northern British Columbia as a prospective tenant, in 2013 the British Columbia government announced a design-build competition for a project that would demonstrate high-rise wood construction in downtown Prince George. Michael Green Architecture (MGA), engineers Equilibrium Consulting and PCL Construction won the $25.1 million Public Private Partnership contract. However, the commission came with some onerous conditions: rigourous testing and documentation of the proposed emerging building technologies, and more, a timeframe of only 15 months for design and construction, with penalties for delays.
If there is another Canadian building so technically innovative, so powerful in its built arguments to the construction industry, achieved with such architectural finesse and completed as quickly as the Wood Innovation Design Centre, I do not know it. Topping out at 30 meters (from concrete foundation to roof), at the time of its construction the WIDC was the tallest mass timber tower in the world at eight storeys (officially six, with a mezzanine and penthouse). The architects and engineers designed components for functionality in a tower at least twice that tall, but this was the height limit set by funding availability and program space needs. That taller all-wood towers are soon to open is no criticism, because this is also one of the more handsome office buildings constructed in Western Canada in years. The building’s program was improvised and evolving, mainly devoted to a new UNBC wood engineering program, some wood-oriented design programs for Emily Carr University of Art and Design, and some provincial forestry-industry-related offices.
By virtue of its occupation and construction, the WIDC is very much a demonstration project. As such, many of its design details exist to show possibilities — there is a strong rhetorical dimension to this tower. For example, Green decided against the skiff of concrete that is typical for the upper floors of mass timber buildings, in his words, “for purity and buildability reasons — mainly to avoid a ‘wet trade.’” By limiting concrete forming trades to the foundation, the design would demonstrate the rapidity of erecting mass timber structures using drop-in dry elements, many of them milled off-site. As well, a concrete floor was not needed for structural reasons, and the flexibility of CLT floor plates of varying thicknesses made for easy in-floor provision of sprinkler, electrical and computer connections. Duct space was minimized through use of perimeter heating and air movement via Jager units with micro-fins. However, MGA’s chosen all-wood construction created significant acoustic challenges, especially since many of the spaces are classrooms that are required to meet UNBC’s high sound-isolation standards, and there is a noisy wood shop off the main lobby, to boot. MGA had to work closely with engineers and builders to meet the standards, developing new details and establishing their worth in testing while under the regimen of a tight and inflexible construction schedule.
A similar set of issues informed the structural connections between columns, beams and CLT floor plates on the high-rise floors. While some high-rise wood towers use standard platform framing, MGA elected for wood-on-wood connections, capitalizing on wood’s vertical dimensional stability. Engineer Eric Karsh has a colourfully apt phrase for the metal connectors, seats and braces often used in North American mass timber construction: “Pots and Pans Connections.” Codes require these metal wood-to-wood connectors be fire-separated, meaning many of these visually interesting building elements have to be bulked up and hidden within enclosures. A key virtue of mass timber construction is the time-tested principle of “charring” as an equivalency to wrapping connections to ensure structural integrity during fires; during a fire the outside layer of wood may burn away, but enough residual structural strength is retained in the remainder to ensure stability. The WIDC’s metal connections — blades, seats, braces — are set within the columns and beams.
This means a clean wood-on-wood aesthetic with most of the structural connections located out of sight. The glowing all-wood clarity of the column and beam connections in the lobby and higher floors are one of WIDC’s finest interior features. “Our design solutions are driven by technical reasons, but we are interested in the aesthetic, the beauty that emerges out of that kind of thinking,” says Green. Similarly, the exposed all-wood sets of exit stairs are an unexpected delight, and here’s hoping that manufacturers soon follow Green’s lead to bulk produce these banal necessities, making more sensuous spaces that render those healthy flights more enjoyable.
Charred surfaces are a design element on the tower’s exterior. MGA alternates panels of naturally aging cedar with charred surfaces of the same using the traditional Japanese technique of shou sugi ban, which in theory creates a low maintenance surface with some flame resistance. A common sense strategy regarding fenestration sets the highest ratio of glazing on the south and east elevations (for light and early heating), and the least on the north (to reduce radiant heat loss) and west (where late day heat gain is an issue).
The variability of the curtain-wall glass and alternation of charred and natural wood create a crisply dynamic presence in downtown Prince George. Prior attempts over the past two decades to architecturally galvanize one of British Columbia’s most troubled downtowns with a postmodern law-courts building or a mastodon-inspired art gallery have failed. WIDC is more transforming of its surroundings because unlike that previous pair, it builds on Prince George’s forestry-based economy and manifests a sheer range of invention balanced with artfulness. This is a demonstration project presenting a collection of arguments on the possibilities of mass timber structure and cladding. It should become a pilgrimage point for every Pacific Northwest architect interested in wood’s new possibilities. When it comes to truly appreciating the substance of architecture, one site visit is worth 1,108,728 page views. However, a bit like the most brilliant but least known of Le Corbusier’s villas — the Maison Curutchet in La Plata, Argentina — WIDC’s geographic isolation may conspire against such in-person encounters.