What would you say if I told you that there is a 70-story, 1,148-foot high-rise on the drawing board made from 90 percent wood? How about an 80-story 800-footer? Maybe 18 stories is more believable? I know, it’s hard to imagine in a city where our wood buildings top out at a mere five stories loaded on top of a concrete podium.
But these new buildings aren’t your grandma’s two-by-fours. Enter Glulam, which stands for glue laminated and cross-laminated timbers (CLT). Think of plywood but different.
Glulam layers small, thin layers of wood together with industrial glue. Glulam weighs a third less than steel and a sixth of concrete. It can be used to span large distances, in fact it appears the limiting factors to length are the machines that make it and the trucks that haul it.
Cross laminating takes solid wood and laminates layers together at 90-degree angles (one layer up, one sideways, one layer up, etc.).
Both techniques result in incredibly strong products that make high-rise wood buildings possible. You may be thinking wood high-rises, or ply-rises as some are calling them, are the answer to a question no one asked. But we did ask.
Plyrises are green. First, they’re wood, but secondly, their manufacturing process generates less greenhouse gasses than steel and concrete. And as long as the building stands, they sequester carbon dioxide (burning wood is what releases CO2).
Increased use of wood spurs forest renewal. In both Canada and Japan there are trees rotting because there is more supply than demand. At first this seems good, but up to half the weight of a tree is CO2 and younger trees suck up CO2 faster, so forest management and tree culling would increase the amount of CO2 removed from the atmosphere. Better managed forests would also reduce the severity of forest fires.
I mentioned burning, didn’t I? Wood contains 15 percent water that must evaporate before burning and Glulam is constructed to form an exterior char layer that protects the core, dramatically increasing the time it takes to burn through. Unlike steel, it doesn’t warp in the heat. Also, according to the fire sprinkler industry, since sprinklers have been in use, most fires are extinguished immediately and those that don’t are contained to the room they originated in. Sprinklers and glulam are safe.
The other thing folks think about with wood is that at a certain point the weight begins to deform and crush the wood, making it unsuitable for taller (heavier) buildings. Because of the way these new wood products are manufactured, they are able to handle the loads. For any architect or curious bystander interested, the bible of timber plyrises, The Case for Tall Wood Buildings, was written by architect Michael Green and you can download and read it here.
I got on this kick seeing a February 8 press release from Sumitomo Forestry announcing the goal to create that 70-story, 90 percent wood high-rise to mark the company’s 350th anniversary in 2041. It’s not coincidental that the 70-story, 350-meter tall building to commemorate their 350th anniversary was announced on the 70th anniversary of the firm’s operation in its current incarnation. Symbolism everywhere.
The only non-wood used will be in exterior cross braces which will be made from a combination of hollow steel tubes and wood. The braces serve to curb seismic impacts in earthquake prone Japan. Elevator shafts will also be non-wood.
There will be balconies on all four sides to provide outdoor space as well as an overlapping grid of greenery that scales the building’s exterior. The building is expected to sequester over 100,000 tons of CO2 as it replants forest to remove more.
River Beech Tower
I just returned from Chicago, the birthplace of the high-rise, where I read about River Beach Tower a collaboration between architects Perkins+Will, engineers Thornton Tomasetti, and the University of Cambridge (UK). Instead of using the exterior steel the Sumitomo project does for wind and earthquake strength, River Beech Tower has created a diamond shaped exterior whereby the diagonal junctions connect to the floor for stability.
A series of intersecting diagonal wooden braces provides strength and beauty to the project. The 80-story concept would contain 300 duplex units with some multi-story connections to form communal public space atriums.
So far this is a concept for Chicago’s masterplan for the Chicago River.
HSB 2023, Stockholm
Another example comes from a design competition in Stockholm for a 34-story residential building constructed of wood around a central concrete core. Above, the top of the building is seen (obviously) where a series of stepped terraces and solar panels add to the greenery of the building. Architectural firm Berg | C.F. Moller’s winning design is scheduled for completion in 2023 to mark the 100th anniversary of Sweden’s largest housing association HSB Stockholm.
Brock Commons, Vancouver
Finally we have a completed project for a 404-room dormitory for the University of British Columbia (UBC). The 18-story project rests on a concrete base. As of September 2017, it was the tallest wood high-rise in the world. The building was designed by Acton Ostry Architects Inc. and included Structurlam, maker of timber products and others.
The building contains two concrete cores containing elevators. The prefabricated exterior panels made assembly a lot quicker than using traditional methods and materials. Once the prefabricated panels were on site, it took just 70 days to construct the 18-story building. Of course being a public university with less grand budgets, Brock Commons isn’t as sexy as the other projects above. However it is built and an example that high-rises and wood can go together in the 21st century.
Canada is particularly keen to encourage wood construction on a larger scale. Many of its northern forests have been infested with a blue beetle that tints the wood blue before eventually killing the tree. Being able to harvest infected trees before they die, the wood is still usable for construction and the glulam process isn’t effected by the blue tint. It’s easy to imagine some wood applications (like flooring) that might not want a blue tint, making the wood unsalable and left to rot in the forest.
Each of these designs demonstrates how wood can be used vivaciously and renewably in the construction of high-rises. It’s a funny evolution. From stone to steel and now to wood, engineering has changed how we are able to utilize previously unheard of materials in construction.
So Dallas, got wood?
Remember: High-rises, HOAs and renovation are my beat. But I also appreciate modern and historical architecture balanced against the YIMBY movement. If you’re interested in hosting a Candysdirt.com Staff Meeting event, I’m your guy. In 2016 and 2017, the National Association of Real Estate Editors has recognized my writing with two Bronze (2016, 2017) and two Silver (2016, 2017) awards. Have a story to tell or a marriage proposal to make? Shoot me an email [email protected].
