By Kira Barrett
North America is on the cusp of a mass timber revolution, and the Waterfront Toronto project is leading the way. But the material faces major obstacles.
Abuilding made primarily of wood conjures public fear of fire, but for a growing number of developers, it evokes opportunity. From constructing towering wooden condominiums, to timber college dormitories, to an entire neighborhood built from trees, experts in “mass timber” are creating buildings of the future.
Sidewalk Labs’ master plan for a futuristic smart city on the waterfront in Toronto includes an entire neighborhood made of wood, called Quayside, with 10 mixed-use building up to 35 stories.
The plan is audacious, considering that in the U.S., there are only 221 mass timber buildings in the works or fully built, according to the American Wood Council’s Kenneth Bland.
In most U.S. cities, mass timber buildings, and specifically tall mass timber buildings, are a rarity, if they exist at all.
But architects, city officials and timber advocates across North America are pushing conventional building codes and public perception because of the drastic impact these structures can have on reducing CO2 through carbon sequestration, compared to traditional concrete and steel.
“I think it’s a big opportunity for a lot of cities out there … The impact on reducing carbon emissions on earth could be dramatic,” Karim Khalifa, director of buildings innovation at Sidewalk Labs, told Smart Cities Dive. “And that gets me excited.”
What is mass timber?
One of the biggest obstacles for city officials is understanding the material. They are more than buildings made of wood — they’re defined by their structure. Steel or concrete buildings with wood accents don’t count, according to Andrew Tsay Jacobs from architecture firm Perkins and Will.
Mass timber buildings use solid wood panels to frame a building’s walls, floors and roofs, creating structures that can reach at least 18 stories, as is the case with the tallest mass timber building in the world in Norway. But these buildings aren’t just pure wood. Mass timber construction utilizes engineered wood, or panels glued together, and there are several types: cross-laminated (CLT), glue-laminated and dowel-laminated timber, with CLT being the most common.
While shorter wood buildings have existed for centuries, CLT panel technology is relatively new. It was developed in Europe in the 1990s, the material was only added to the international building code in 2015. Even then, all-wood buildings were capped at six stories, though that will change to allow taller structures in 2021.
By Robert Dalheim
COLLEGE PARK, Md. – The research team behind “super wood” is at it again – this time engineering a wood that’s capable of staying 12 degrees cooler than regular wood.
Researchers at the University of Maryland and the University of Colorado hoped to find a passive way for buildings to dump heat sustainably. The solution is wood – it is already used as a building material, and is renewable and sustainable. Using tiny structures found in wood – cellulose nanofibers and the natural chambers that grow to pass water and nutrients up and down inside a living tree – the researchers engineered wood that radiates away heat.
The UMD team soaked basswood in a solution of hydrogen peroxide, which destroys the wood’s lignin. The team then used a hot press to compress the remaining cellulose and hemicellulose components together. To make it water repellent, they added a super hydrophobic compound that helps protect the wood.
Wood may seem more at home in log cabins than modern architecture, but a specially treated type of timber could be tomorrow’s trendy building material. Today, scientists report a new kind of transparent wood that not only transmits light, but also absorbs and releases heat, potentially saving on energy costs. The material can bear heavy loads and is biodegradable, opening the door for its eventual use in eco-friendly homes and other buildings.
“Back in 2016, we showed that transparent wood has excellent thermal-insulating properties compared with glass, combined with high optical transmittance,” says Céline Montanari, a Ph.D. student who is presenting the research at the meeting. “In this work, we tried to reduce the building energy consumption even more by incorporating a material that can absorb, store and release heat.”
As economic development progresses worldwide, energy consumption has soared. Much of this energy is used to light, heat and cool homes, offices and other buildings. Glass windows can transmit light, helping to brighten and heat homes, but they don’t store energy for use when the sun goes down.
Three years ago, lead investigator Lars Berglund, Ph.D., and colleagues at KTH Royal Institute of Technology in Stockholm, Sweden, reported an optically transparent wood in the ACS journal Biomacromolecules. The researchers made the material by removing a light-absorbing component called lignin from the cell walls of balsa wood. To reduce light scattering, they incorporated acrylic into the porous wood scaffold. The team could see through the material, yet it was hazy enough to provide privacy if used as a major building material. The transparent wood also had favorable mechanical properties, enabling it to bear heavy loads.
Building on this work, Montanari and Berglund added a polymer called polyethylene glycol (PEG) to the de-lignified wood. “We chose PEG because of its ability to store heat, but also because of its high affinity for wood,” Montanari says. “In Stockholm, there’s a really old ship called Vasa, and the scientists used PEG to stabilize the wood. So we knew that PEG can go really deep into the wood cells.”
Known as a “phase-change material,” PEG is a solid that melts at a temperature of 80 F, storing energy in the process. The melting temperature can be adjusted by using different types of PEGs. “During a sunny day, the material will absorb heat before it reaches the indoor space, and the indoors will be cooler than outside,” Montanari explains. “And at night, the reverse occurs — the PEG becomes solid and releases heat indoors so that you can maintain a constant temperature in the house.”
By Andrew Moore
The tiny rod-like structures have been shown to improve the strength and durability of concrete structures and reduce the carbon footprint of manufacturing cement.
If you were to walk through downtown Greenville, you would likely notice several landmarks, including the Liberty Bridge and the old county courthouse.
While these iconic structures are unique in their own right, they share one commonality: They’re made of concrete. The coarse, gray material is the very foundation of modern infrastructure. It’s been used in the construction of everything from buildings and bridges to roads and sidewalks.
But despite all its benefits of strength and durability, there’s a major downside to using concrete.
The production of cement, which when mixed with water forms the binding agent in concrete, accounts for 5 to 10 percent of all human-caused carbon dioxide emissions, according to the International Energy Agency. These emissions have been on the rise since the industrial revolution and remain the leading cause of global warming.
Over the past decade, though, researchers from across the country have been working together to create a cleaner version of the versatile building material. And now they plan to test the capabilities of their environmentally friendly alternative in Greenville.
The U.S. Endowment for Forestry and Communities, a Greenville-based environmental nonprofit, has partnered with the U.S. Forest Service, Oregon State University, and Purdue University to study a concrete mixture infused with cellulosic nanomaterials.
Cellulosic nanomaterials are produced by breaking down wood to its smallest, strongest components through mechanical and chemical processes similar to making paper. These tiny rodlike structures have diameters 20,000 times smaller than the width of a human hair and can be seen only using an electron microscope, yet they are as strong as steel with only one-fifth the weight.
“Researchers are testing these cellulosic nanomaterials in a wide range of applications from substrate for computer chips, they don’t warp under heat like plastics do, to car and airplane bodies, lighter and stronger than steel,” said Dr. Alan Rudie, a chemist with the U.S. Forest Service’s Forest Products Laboratory in Wisconsin, in a news release. “Our team expects that concrete will be among the first commercial applications.”
By George Plaven
Timm Locke relishes a chance to drive around Portland and showcase the latest commercial buildings made with mass timber, a construction material that uses wood beams and panels instead of concrete and steel.
First stop: Albina Yard, a four-story office building that opened in 2016 featuring cross-laminated timber panels from D.R. Johnson, a lumber company south of Roseburg.
Every piece of cross-laminated timber — or CLT for short — is prefabricated, designed for a specific part of the building, said Locke, director of forest products at the Oregon Forest Resources Institute. That means buildings go up faster, with fewer workers.
Wood is also environmentally superior to steel and concrete, Locke said, because it sequesters carbon and takes less energy to produce.
“There are so many benefits, it doesn’t matter which one you choose to start with,” Locke said.
First developed in Europe, mass timber is now catching on in the U.S., and Oregon is working to position itself as the industry hub, kick-starting rural economies that have traditionally relied on forest products. On Aug. 1, Oregon became the first state to approve language in its building codes allowing for wood-framed buildings up to 18 stories tall.
By Emily Pollock
M-Fire’s fire-inhibiting wood looks increasingly important in an industry turning back to wood buildings.
The phrase “wood buildings” conjures up images of flammable, unsafe architecture, but M-Fire Suppression Inc. is looking to change that picture. And it wants its fire-resistant wood to be the new face of ecologically friendly building.
One of the most common tests of a material’s fire resistance is a spread test, where inspectors measure how long it takes fire to spread across the material as compared to control materials. Class A is the most fire-resistant class, and M-Fire is currently the only company making Class A fire-protected cross-laminated timber. To do that, the company infuses wood with surfactants that allow fire inhibitors to migrate into the pockets of oxygen in the wood. The result is a product much eco-friendlier than most traditional fire inhibition. M-Fire is currently the only Class A fire inhibitor with UL Greenguard Gold certification, which means that it’s safe around children and schools.
“We don’t even like the name fire retardant near our brand. We’re a fire inhibitor,” said Steve Conboy, the company’s chairman and general manager. “What happens is, we inhibit fire because we break the chemical reaction in the fire.” The inhibitor breaks the chain of free radicals (H+, OH- and O-) released during combustion, giving the fire nothing to feed on.
The fire protection results in what Conboy calls “defended carbon”: carbon that is stored in the wood and will never be released into the atmosphere. A carbon-absorbing building material gives M-Fire’s wood a distinct advantage over carbon-producing alternatives like structural steel.
by Jack McManus
Space Popular’s design gathers service functions into a central prefabricated core (resembling a Nordic hearth) that DIY-ers can build their own house around.
Solutions from the past can often provide practical answers for the problems of the future; as the London-based design and research firm, Space Popular demonstrate with their “Timber Hearth” concept. It is a building system that uses prefabrication to help DIY home-builders construct their own dwellings without needing to rely on professional or specialized labor. Presented as part of the ongoing 2018 Venice Biennale exhibition “Plots Prints Projections,” the concept takes inspiration from the ancient “hearth” tradition to explain how a system designed around a factory-built core can create new opportunities for the future of home construction.
Realized in the form of a brightly-painted model in the exhibition space at Serra dei Giardini, the Timber Hearth system gathers all the service functions, appliances, and fittings that require professional installation in typical residential buildings and contains them within a prefabricated hearth-like structure.
Fabricated in a factory and sized for shipping in one piece, the core is then installed on site and connected to service grids. After that, the remaining construction (including building the floor platforms, partition walls, facade, and roof) can be completed by the homeowners, either by traditional or contemporary timber-frame methods. According to the designers, this affords reasonably-equipped makers the flexibility, freedom, and affordability to build their own perfect home.
By Robert Dalheim
Freres Lumber Co. hopes its new-to-market, veneer-based massive plywood panels will revolutionize construction.
The Oregon-based manufacturer announced its new veneer-based panels in October after more than a year of development and performance testing at Oregon State’s Advanced Wood Products Laboratory. Freres says the panels, known as Mass Plywood Panels (MPP), could be used for floors and walls in multi-story commercial buildings, and they could be made to order.
Designed to be an alternative to cross-laminated timber, Freres’ massive panels can be as much 12-feet wide, 48-feet long and 2-feet thick.
Freres says there are many potential benefits:Structures made of MPP could be made in days instead of months, says Freres, and use 20-30 percent less wood than cross-laminated timber. The lightweight nature of MPP could reduce truckload transport costs. Large format panels could be manufactured at a facility to include window, door, and all other required cut-outs – minimizing waste and labor on the job site.