Seattle’s first tall timber housing project, Heartwood, is now open and accepting tenants with Timberlab—one of North America’s largest mass timber manufacturers – confirming that the ‘fully circular’ 126-unit apartment block is America’s first Type IV-C built under the International Building Code.
A key part of the 2021 International Building Code (or IBC), Type IV-C allowed Skipstone, the developer, Community Roots Housing, the owner as well as atelierjones, DCI Engineers and Swinterton, the architect, engineer and contractor, to build a timber tower up to nine storeys and with 2-hour fire resistance.
“The project is the first tall wood building permitted by Seattle and received a $250,000 Wood Innovation grant from the U.S. Forest Service,” Timberlab said, adding that the project validates the feasibility of Type IV-C multifamily housing” nationwide.
According to Timberlab, the timber system is lighter than steel and concrete and allows for faster assembly times. In effect, this means that the decision to use timber allowed the developer to add an extra floor of units (compared to the conventional 5-over-2 approach) and speed up the construction schedule.
“The glulam post-and-beam frame is laid perpendicular to the corridor, aligning with demising walls between units,” Timberlab said: “This layout facilitates the horizontal distribution of services throughout the building and allows for strategic encapsulation of some timber elements as a cost-saving strategy.”
To deliver a fully exposed timber structure, Timberlab worked with the design team to develop a unique wood-to-wood bearing connection, eliminating steel hardware and saving time and money.
“Utilising a wood-to-wood bearing system, we reduced steel connections, saving costs and creating schedule efficiencies during construction,” it said, with cuts made by CNC machines added to install intumescent fire tape, routed into beam ends and around columns to provide floor-to-floor fire separation.
“By eliminating steel connectors, reducing the number of bolts and bolt holes, and utilising layers of slip sheet and gypcrete for sound attribution on top of the CLT in place of a traditional composite slab, the project can be easily disassembled at the end of its life cycle, reducing wood fibre waste and allowing for immediate reuse of the CLT.”
Timberlab on the innovative wood-to-wood bearing system used on the project.
Last week, Wood Central spoke to Jared Revay, Timberlab’s Director of Manufacturing, who said the growing demand for design for disassembly is pushing Timberlab to develop newer and more innovative mass timber applications.
“There is this idea that we could build prefabricated wood buildings that can be disassembled one day and the wood used for something else. I mean, wood can last for centuries if you take care of it, right? And so it all comes down to smart design and smart maintenance.”
Mr Revay on the potential for prefabricated timber buildings to be recycled and reused as part of a fully circular economy.
Mr Revay, one of nine international presenters at Timber Construct, Australia’s largest timber conference, will speak live from the airport just hours before its opening: “It’s cool that I can present live from the airport, and it’s pretty exciting to share the project with all the delegates and attendees,” Mr Revay said told Wood Central it’s most recent podcast.
“So far, we have 39 presenters lined up,” said Andrew Dunn, the organiser of Timber Construct, who said the Melbourne event “focused on materials and design, prefabrication, and building techniques.”
“Tickets are still on sale for the August 12 and 13 event,” Mr Dunn said, “so secure your early bird tickets before it is too late.”
