Los Angeles Mixed-Use Structure is Utilizing CLT
To avoid ongoing supply chain issues, Boston-based Shawmut Design and Construction has planned to use cross-laminated timber (CLT) for a mixed-use office building in Los Angeles.
According to reports, Shawmut is working in conjunction with Santa Monica, California-based real estate firm Redcar Properties and Portland-based architecture and design firm Lever Construction on the 75-foot-tall, 125,000-square-foot mixed-use project.
Once completed, the structure will be one of the tallest CLT structures in Los Angeles.
About the Project
Roughly 30% completed after breaking ground in the city’s Chinatown district downtown last April, the new structure is the adaptive reuse of a single-story retail mall. The old structure had been reportedly vacant for the last 30 years.
Split into two sections, the new five-story building will feature a vertical garden courtyard between the office wings. The structure’s design also features several outdoor terraces and decks, as well as open-air circulation elements, which were created with the help of landscape architecture firm James Corner Field Operations.
The installation of CLT launched just last month after Shawmut received materials from British Columbia-based mass timber manufacturer Structurlam. The CLT, which is reported to be 5-ply, is thinner than normal, due to the structure’s hybrid construction and reinforced concrete decks on every floor.
Other CLT material benefits include fire- and earthquake-resistance. In addition, the CLT allows for less concrete, reducing the building’s carbon footprint. (CLT is also a carbon negative material.)
The project is slated to use 364 panels of CLT, totaling 75,776 square feet. According to Greg Skalaski, Executive Vice President-West in Shawmut’s Los Angeles office, the project would have used more CLT if code-mandated limitations permitted it.
Shawmut builds 75-foot-tall LA office building using cross-laminated timber: Employing C LT, the company dodged supply chain issues and high fabrication prices. One executive said… https://t.co/d6Bqs3lKlH #constructionjobs #civilengineering #construction #constructionnews #civil pic.twitter.com/aM1qKK5NKl— constructionjobs.design (@constructionj11) November 17, 2021
Although there have been ongoing uncertainties about lumber pricing and availability, Skalaski noted that the use of CLT on the project “adds stability to the supply chain” and that it was a “California-type” form of building technology.
“The connection with the outdoors has always been there with buildings in California and you look at some of these really great houses in California, there's always this indoor-outdoor component, the doors are open, the windows are open. It's that kind of environment that is now being transformed into the CLT office building,” Skalaski said.
The project is slated to be completed in August 2022.
Mass Timber Elsewhere
In August, officials behind what is slated to be the tallest mass timber building in the United States reported that construction was on track for a February 2022 completion.
The $150 million structure in Cleveland, Ohio, replaces an old strip mall and is slated to host about 300 apartments, ground-floor retail space and a top-floor event venue. At the time of the progress update, about 80% of the 36,000 square feet of the ground floor already had tenants committed.
Reportedly, the timber used for the project is blond hem-fir and spruce trees harvested in the Austrian Alps. The structure was designed by Hartshorne Plunkard Architecture of Chicago.
James Litwin, Vice President of Construction for, Harbor Bay Real Estate Advisors LLC, the Chicago-based company behind the project, noted that while the timber is costing about $38 a square foot in comparison to $35 for concrete, the speed that workers are able to move on the job is making up for that cost difference.
Harbor Bay chose to have its mass timber components manufactured and shipped via containers from Binderholz GmbH, based in Austria, also because of costs.
The project is aiming for LEED Gold certification.
While Intro Cleveland will hold the title for tallest U.S. mass timber building, it will only do so for a short period of time, as a Milwaukee project, dubbed “Ascent,” is slated to complete next summer.
Construction began on the 25-story Ascent last September. Upon completion, that tower will stand 284 feet tall and house 259 apartment units, along with retail, parking, a swimming pool and fitness center.
Proposed in October 2018, the initial design of the high-grade timber-based mixed-use tower involved 21 stories and was predicted to be one of the tallest buildings in the world of its kind, according to its developer, New Land Enterprises LLP (Milwaukee).
The then-predicted 238-foot tower would feature laminated timber—columns and beams created by pressing layers of wood together—encompass 410,000 square feet and was designed by architectural firm Korb + Associates (Boston), with Thornton Tomasetti as the project’s structural engineer.
Months later, at the end of January, the Milwaukee City Council’s City Plan Commission unanimously recommended that a requested rezoning at 700 East Kilbourn Avenue move forward, a first step forward in making the residential tower a reality.
According to The Architect’s Newspaper, the first five stories of the mixed-use development would feature cast-in-place concrete, with up to 8,100 square feet of ground-floor retail and four stories of enclosed parking above that. Moving farther up the tower, the remaining 16 stories were slated to contain 205 rental units and would be built from mass timber fastened with steel connectors.
Partner and project architect Jason Korb reported at the time that because the project planned to use the prefabricated timber, the 16 residential stories could be installed in only four months. Additionally, the mass timber’s structural elements were stated to be fire resistant, in the sense that in the event of a fire, they would only char and not burn through.
In March 2019, the rezoning for the residential tower was unanimously approved by council and, in May, the United States Department of Agriculture’s Forestry Service division awarded the project with an undisclosed grant. In total, the division awarded 41 grants totaling $8.9 million, suggesting that an average size grant would total roughly $217,000.
Urban Milwaukee reported that the received grants would be used for support engineering work and was already engaging with Catalyst Construction (Milwaukee) on pre-construction plans.
By August, another proposal was sought by city zoning approval to add two floors to the Ascent tower, bringing the structure’s total height to 23 stories.
However, in September, the Milwaukee Plan Commission and the Zoning, Neighborhoods and Development Committee unanimously approved changes to the project, making the structure even taller.