The latest proposals are getting higher. An 80-story timber tower in London, 40 stories in Stockholm marked by a distinctive timber façade. Completed and in-process projects are also reaching new heights: the 14-story TREET residential tower in Norway (PDF) (completed in 2015 and surpassing Australia’s 10-story Forte tower as the tallest wood building in the world), the 18-story Brock Commons student residence in British Colombia and the 24-story HoHo project in Vienna designed by RLP Architects, set to be completed in 2017 and 2018, respectively.
In what has been described as a craze, a revolution and the dawn of timber, tall wood buildings have been taking the architecture and design world by storm. Slowly but surely, story by story, these towers of timber have moved from concept to reality and set in motion a 21st-century method for building skyscrapers.
The Game Changer
“This is the future of architecture”
“This is the future of architecture,” says Andrew Waugh, principal of London-based Waugh Thistleton Architects, which is behind several precedent-setting timber towers, in an interview for ArchiExpo. “And now it’s not only happening in the U.K. but all over the world.”
For over a century, concrete and steel skyscrapers have dominated our skylines. But as climate change and a demand for more urban housing has reached a critical point, the need for a building solution that requires less energy and offers a softer carbon footprint has come to the forefront.
What has been the game changer is mass timber—layers of wood laminated together to make massive panels. This includes, among other types, cross laminated timber (CLT), laminated veneer lumber (LVL) and laminated strand lumber (LSL); this engineered timber offers a strong, solid material that creates the stability to build higher.
“Mass timber buildings are changing the scale of what is possible to be built in wood around the world,” cites the 2012 report, The Case for Tall Wood Buildings, written by Michael Green, principal and founder of MGA and one of the leaders in the tall wood building movement. Lighter than steel and concrete, these often prefabricated modules are easier to transport and allow for quicker build times. Durable, resilient and beautiful, wood’s strongest benefit is its environmental advantages.
“When harvested responsibly,” says Green. “Wood is the only carbon neutral building material that can reduce green house gas missions and actually sequester carbon in buildings.
Going Vertical Differently
Projects around the world demonstrate the various approaches to mass timber construction. Completed in 2014, MGA’s 29.5-meter Wood Innovation and Design Centre in Prince George, British Colombia used CLT floor panels, Glulam (glued laminated timber) columns and beams and mass timber walls. The project is an example of the firm’s Creative Commons FFTT (Finding the Forest Through the Trees) system, which was introduced in the 2012 report as “a predominantly wood system with a solid wood central elevator and stair core and wood floor slabs. Steel beams are used to provide ductility in the system to address wind and earthquake forces. Concrete has been used for the below grade areas of the structure.”
In what will be the first timber building realized in the U.S. in more than 100 years—and the tallest in North America when it’s completed this autumn—MGA’s 22,000-square-feet Minneapolis T3 office building uses over 1,100 nail laminated timber (NLT) panels (most made from lumber from trees killed by the mountain pine beetle) and leaves the mass timber columns and floors slabs exposed, demonstrating the aesthetic and health benefits of a wood interior.
In Vienna, the mixed-use HoHo high-rise is an example of a timber-hybrid construction, which pairs mass timber with other materials. Here, with the service core constructed of solid reinforced concrete, which also acts as a support to the timber structure, 75 percent of the building from the ground floor up is made from timber. Ease of construction is achieved through “the stacking of four, prefabricated serial components,” as described on the project’s website. “Support, joist, ceilings panels and façade elements.”
Waugh Thistleton is behind what was the tallest modern timber building in the world at the time of its completion in 2009. Rising nine stories and constructed from prefabricated CLT panels, the Murray Grove residential building was one of the first with load bearing walls, floor slabs, stairs and lift cores constructed from timber. “The journey we started with Murray Grove in 2008 is now an international campaign,” Thistleton said in an interview for ArchiExpo.
The firm is now working on a 121-unit CLT constructed residential building, which is scheduled for completion in early 2017. Dalston Lane, located in London’s Hackney borough, which encourages timber construction, is being touted as the largest CTL project, by volume, in the world.
Developments to Manage
Although building code changes are showing signs of more acceptance of tall wood construction (Australia was the latest), perceptions still have a ways to go before building departments see the full advantages of wood over concrete and steel. Architects embracing tall timber are attempting to quell fears about fire by bestowing mass timbers advantages which char on the outside, creating an insulation and thus a slow burn.
Further developments include a look to the creation of mass timber with bamboo, which has a high growth rate and is plentiful throughout the world. In future our cities could go from concrete jungles to urban forests.
“It’s a very exciting time, the impetus is growing,” Waugh Thistleton continued in an interview for ArchiExpo. “And going tall for high density environmentally sustainable solutions is the only way we can viably extend our cities.”
Skyscrapers: High on Wood, featured image: Ten-story residential condominium building on 18th Street West NYC by SHoP Architects. The project is in its design development phase.