With $3 million up for grabs and a backing by the White House, it's no wonder the US Tall Wood Building Prize Competition has drawn a global audience.
The first batch of winners have been chosen in the climate-driven initiative, which was announced by the White House Rural Council and the United States Department of Agriculture (USDA) last year.
Leading architecture firms SHoP and LEVER will bring their winning wooden ambitions to life in New York and Portland, Oregon.
The projects have now become two of the most anticipated buildings for the wood industry. They also provide a great opportunity to represent the possibilities in tall wooden construction in the US.
The two winning proposals – Framework and 475 West 18th – were selected by a panel of distinguished jurors in the architecture and engineering fields who are familiar with innovative wood building systems.
“The US wood products industry is vitally important as it employs more than 547,000 people in manufacturing and forestry, with another 2.4 million jobs supported by US private forest owners,” said US Secretary of Agriculture Tom Vilsack.
“By embracing the benefits of wood as a sustainable building material, these demonstration projects have the ability to help change the face of our communities, mitigate climate change and support jobs in rural America. I look forward to seeing how these two buildings help lead the way in furthering the industry.”
Each building was required to showcase the safe application, practicality and sustainability of a minimum 80-foot structure that uses mass timber, composite wood technologies and innovative building techniques.
Wood is the only building material that sequesters carbon, making it an ideal environmentally sound alternative to concrete, masonry and steel.
Vilsack told The Washington Post that wood construction also provides an opportunity to support the restoration of American forests.
“There’s 45 million acres of that diseased wood that’s available, and that currently presents a fire risk,” he said. “And so, to the extent that we can create this opportunity, it will result, I believe, over time, in more of that diseased wood being removed as opposed to burned.”
LEVER’s winning entry, a 130-foot/12-storey mixed-use project, was officially named Framework: An Urban + Rural Ecology.
The building stands to become one of the first tall buildings in Portland and will feature five levels of offices, five levels of workforce housing, ground floor retail and a rooftop amenity space.
The firm plans to use its $1.5 million in prize money for research.
“The USDA grant will allow the project to engage the exploratory phase including the research and development necessary to utilise Cross Laminated Timber (CLT) and other engineered wood products in high-rise construction in the United States,” said the firm.
“This includes working with Portland and Oregon code authorities during the pre-permitting process to define and perform the necessary testing and peer review to demonstrate the feasibility of tall wooden buildings.”
Thomas Robinson, principal of LEVER Architecture said his team is expected to incorporate new structural and architectural technologies that include an engineered wood core and lateral system for seismic integrity and CLT floor panels fabricated up to 50 feet in length.
The framework that will incorporate a post-tensioned rocking CLT core stands to be a benchmark to the industry.
“This is a mission driven project that embraces regional sustainability that unites rural and urban economies,” the firm said. “This project will also be a catalyst to align the regulatory framework with the technology for mass timber construction in the US.”
“The relationship of our cities to our rural communities, what we call ‘forest to frame,’ is strengthened by Framework,” added Anyeley Hallova, a partner at project^, the real estate developer for Framework. “On a national scale this project will be catalytic, leading to more tall wood buildings, driving more wood products and wood product innovation, and boosting rural economic development.”
The second project, 467 West 18th Street, was developed by 130-134 Holdings LLC, in partnership with Spiritos Properties, SHoP Architects, Arup, Icor Associates, and environmental consultancy Atelier Ten.
The 120-foot/10-storey residential building will feature commercial space at ground level and a limited palette of materials – mass timber columns, beams, shear walls and floors.
The project has notable environmental benchmarks, targeting LEED Platinum certification and pursuing higher levels of sustainability not yet captured in the LEED system.
“By combining aggressive load reduction with energy efficient systems, the project team anticipates reducing overall energy consumption by at least 50 per cent relative to current energy codes,” the firm said.
SHoP is looking to “create a holistically better approach in terms of energy performance and carbon footprint, construction tolerances and speed of erection, and life-safety performance matching other buildings of the same height built of conventional materials.”
The firm’s $1.5 million prize will go toward researching architectural, structural and fire projection solutions for a building system that is relatively new to North America.
The project also has impressive carbon sequestering estimates.
“Our preliminary studies of the full timber structural system solution estimate a potential reduction of approximately 700,000 kg – 1,200,000 of CO2 equivalents in the range of 30 per cent up to 100 per cent,” said SHoP and David Farnsworth, principal at Arup.
“This rather high variability is dependent on where the final sourcing of the timber comes from, how its use at the end of life is defined, and as well the final material selections for other elements of the building.”
For the fire sceptics, SHoP noted the natural fire resistance of wood.
“Wood has a natural process to combat fire: When it burns, it forms a char layer on the exterior that protects cold wood inside,” the firm stated. “This charring occurs at a predictable rate of 1.5 inches/hour and so the size of structural members are increased in order to provide a fire rating of up to three hours. This is not dissimilar to how steel members are used in construction by adding protective coatings to the steel to provide fire-resistance, except in the case of wood, it is an inherent property of the material itself.”
The timber structure will be elevated off the ground by extending the concrete sub-structure above-ground and potentially incorporating a physical termite barrier.
“This is typically the preferred approach (to termite concerns) rather than chemical treatments,” the firm said.
While the US building code does not allow for more than six storeys of wood frame construction, both winning teams have obtained early permission to proceed with their projects.
475 West 18th Street is set to join New York’s skyscraper skyline with construction commencing in fall 2016, while Framework is expected to be completed by December 2017.