Brookfield Plans Largest Mass Timber Office Property
Don’t knock wood. Brookfield Properties is joining a growing wave of prominent U.S. developers turning to wood as it plans to build what it bills as North America’s largest mass timber office property at its mixed-use Pier 70 project in San Francisco.
The New York-based company said a new, 310,00-square-foot, 85-foot-high building made largely of wood will be the first ground-up office building at Pier 70, the developer’s $3.5 billion project on a historic former ironworks and ship-building site on the San Francisco waterfront.
Housing, office and light-manufacturing spaces, parks, arts venues and other elements in rehabilitated historic buildings are planned for the 28-acre community, with design reviews now underway by San Francisco city and port officials. Brookfield and its project partners have targeted a spring 2020 construction start for the six-story mass timber office building, expected to be completed within two years.
In a statement, Brookfield and its project designers touted the use of wood as a renewable resource with a lower carbon footprint than other structures. The office building plans call for featuring cross-laminated timber floor slabs and glue-laminated timber columns and beams, along with steel seismic framing and metal cladding.
"The Pier 70 office building will make a statement about how mass timber technologies are pushing design and construction towards environmentally sustainable design solutions that better connect the workplace to the natural environment," said Corey Martin, principal in Hacker Architects of Portland, Oregon.
Project leaders said cross laminated timber is a relatively new building material generally best used for mid-rise buildings. "By applying emerging technologies and innovative designs to the structures we’re building here, we are reinforcing that Pier 70 will be a thriving place for creative industries in San Francisco," said Cutter MacLeod, Brookfield Properties’ senior manager of development.
According to Washington, D.C.-based Woodworks, a nationwide trade group representing the wood products industry, the U.S. as of October had a total of 664 mass-timber projects – including multifamily, office and other commercial and institutional structures – either built or currently in design in 48 states.
While wood doesn’t necessarily help cut construction costs, there can be utility savings once buildings are open. A recent report from ReThink Wood, a wood products industry coalition, said a school district in Washington state saved $4.3 million in utility costs between 2004 and 2011 after rebuilding roughly 20 buildings with wood frames.
Small Environmental Effect
Hacker Architects’ Martin said the amount of resources and energy it takes to produce cross-laminated timber slabs is a fraction of that required to produce equivalent-sized steel or concrete components. He cited data from the Oregon Forest Resources Institute, indicating that it will take about 90 minutes for that state’s managed timberlands to grow the amount of wood that will be used in the Pier 70 building in San Francisco.
Also, the lighter weight of wood can help lower foundation costs and speed up construction, since off-site prefabrication is done in advance of building assembly, Martin said. Pier 70 is expected to see its construction time reduced by about four to six months compared with a similar-sized concrete building.
Brookfield has joined a mini wave that now also includes other prominent global commercial developers such as Houston-based Hines and Montreal-based Ivanhoé Cambridge, with projects underway in several major cities.
For instance, Hines is planning to build several office buildings made entirely of timber in Houston, Dallas and other Texas cities. Hines is also partnering with Ivanhoé Cambridge and Chicago-based McCaffery Interests to develop a six-story wood office building in Denver called T3, named for its building design incorporating timber, transit and technology.
Brookfield and its San Francisco project designers said timber floor panels will laminate layers of solid wood that can change direction in each subsequent layer, making the panels strong in two directions and giving them strength comparable to traditional building materials like steel or concrete.
Designers said mass timber projects are made with strong and flexible materials that can be light while still performing well in seismic events. Such structures include the addition of wood for a "char layer" that can resist fire better than steel, which otherwise would need added fire-proofing for a building the size of the Pier 70 office property.
"Mass timber is structure, finish and fire-proofing, where the size of the wood elements can be increased to withstand fire," Martin said. "Exposing the wood provides an exceptional finish, which minimizes the need to add ceilings and other fire-proofing material."
