Toronto's first commercial timber-framed building is slated for completion by the end of the year, and excitement is mounting as the precedent-setting 80 Atlantic Avenue races to become the first of potentially many timber frame projects across the city. The Toronto Society of Architects recently organized a tour of Hullmark Developments' 80 Atlantic, which was led by Richard Witt and Wayne McMillan of Quadrangle.
The tour started with a walk-around on the exterior of the 5-storey building, exploring the relationship between 80 Atlantic and the neighbouring 60 Atlantic, previously completed by the same team of Hullmark and Quadrangle. The two buildings actually share the same property, so since 60 Atlantic is a heritage building, 80 Atlantic was also subject to the same heritage requirements. Witt explained the dialogue between the two buildings across the shared sunken courtyard, with main circulation spaces and expanses of contemporary glazing mirroring each other on the two structures. As well, 80 Atlantic is pulled back from 60 Atlantic at its southwest corner to allow the heritage facade to remain exposed. A cantilever above the third floor bumps 80 Atlantic back out to the edge of the neighbouring building, which can be seen at the far corner of the courtyard in the image below.
The exterior cladding is nearing completion, with the porcelain panels being installed on the east elevation. Witt described the design process of the building, how the contemporary punched-out window pattern of 80 Atlantic was inspired from the typical window patterns of the surrounding heritage buildings in Liberty Village. The south facade is considered the principal facade of the building, so it was given full wall-to-ceiling glazing, while the other elevations are more solid with the use of porcelain.
We enter the building from the main entrance on Atlantic Avenue. In front of us, a ramp leads down along the south elevation of the building to the main lobby, while to our right, the large retail space is taking shape. The structure of the ground floor is actually concrete, not timber like the rest of the building. Due to the different retail and office uses between the ground floor and upper floors, a higher fire rating was required to separate them, so it was more practical to opt for a concrete structure. As well, given the higher ceilings on the ground floor, concrete provided more flexibility for column spacing and placement.
We head down the ramp to the main lobby space. Along the way, Witt points out that a steel structure was used for the ramp pavilion in order to avoid having columns by cantilevering the I-beams from the main building. There are two other cantilevers in the building—the east elevation and at the southwest corner—where steel was also used. Glazing on both sides of the ramp provide views into the courtyard and the retail space.
The main office lobby features a staircase that connects to the retail spaces. Not knowing what retail tenants would eventually set up shop, Quadrangle envisioned a certain openness and connectivity between the retail and office components of the project, so the staircase was meant to provide easier access between the two. The lobby now awaits its final interior finishes.
Heading upstairs, we arrive at the main event: the exposed timber office spaces of the upper floors. The first noticeable thing is the smell; instead of the earthy odours of concrete or metallic smell of steel, the group is greeted by the scent of fresh-cut wood. The open plan and expansive floor plates feature timber columns and ceilings spreading outward from a concrete core, ending in panoramic views through the large sections of glazing.
The structure is composed of glulam beams and columns, on which are installed nail-laminated timber (NLT) panels for the floor plates. The floor section is composed of the exposed NLT at ceiling level, on top of which is an acoustic layer that includes a concrete pad, which is used to minimize deflections in the floor and to provide an even surface.
On top of the concrete, a 400mm (16") raised floor is constructed, which will hide all of the mechanical and electrical equipment within the plenum space. The only exposed equipment on the NLT ceiling will be the light fixtures and sprinkler pipes. A final floor finish will eventually be applied to the raised floor tiles, which currently are steel or cement.
Witt described some tricky situations they ran into using timber structure and how they were able to work around them. One was the connection from column to column between floors, in both a structural and fire safety sense. Steel connectors were used that pass through the floor at each column, allowing a break in the timber frame at each floor level. The gypsum seen around the base of the connector in the photo below is to protect the steel from fire, and the raised floor will slot in on top of the gypsum. Quadrangle raised the steel angle slightly above floor level to create an aesthetic reveal at the base of the column, hinting at the assembly that lies below.
Another issue Quadrangle had to work around was vertical penetrations - mechanical ducts, electrical conduits, plumbing, and other equipment that must pierce through the floor. They avoided having to deal with these penetrations and the firestopping measures they would require by having all vertical risers pass through the core, and then fan out horizontally at each floor level through the raised floors. This kept the ceiling clear of unsightly holes and equipment, leaving the wood to be fully exposed and uninterrupted.
As the group passed through each floor, it was clear that progress is moving quickly, with all structure in place, the raised floor being installed, and preparation being done for the final finishes. Ending the tour on the fifth floor, a panoramic view toward Exhibition Place and Lake Ontario could be seen from the expansive glazing on the south facade.
Keep checking back for updates as 80 Atlantic comes together, but in the meantime, additional information and images can be found in our database file for the project, linked below. Want to get involved in the discussion? Check out the associated Forum thread, or leave a comment in the field provided at the bottom of this page.
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|Related Companies:||Cushman & Wakefield, DeepRoot Green Infrastructure, Eastern Construction, Hullmark, Kramer Design Associates Limited, LiveRoof Ontario Inc, Quadrangle, RJC Engineers, Trillium Architectural Products, Vertechs Design|