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Dec
11

Circular economy: salvaged lumber

Every year, about 500 buildings in Seattle and over 400 homes in King County are demolished. This creates a large volume of lumber that is often as good as, or even better quality than new lumber. By collecting and reusing this lumber, and scrap lumber from new construction, we can create a more sustainable, circular system. But to do this, we need more regional infrastructure to process salvaged lumber.

Learn about our work and resources concerning salvaged lumber.

Clean wood, salvaged lumber, and circularity

Over 60,000 tons of clean wood each year ends up in King County’s landfill, with even more burned as hog fuel. Research shows that these disposal methods are more harmful to human health and the environment compared to reuse. Diverting clean wood for reuse or recycling offers significant benefits, helping King County advance our climate, waste reduction, and equity and social justice goals.

Scrap lumber at Bow Lake Recycling & Transfer Station
Scrap lumber at Bow Lake Recycling & Transfer Station

Most of the clean wood being burned or landfilled is dimensional lumber and pallets. By changing how these materials are handled, we can ensure more of it is reused in buildings and construction materials.

Salvaged lumber examples courtesy of Sledge Seattle
Lumber salvaged by Sledge Seattle

By deconstructing homes instead of demolishing them, we can save resources and reduce impacts. A study of Portland’s 2016 deconstruction law showed that about 7.6 metric tons of CO2e is saved for every house that is deconstructed rather than demolished. A typical 2,000 square-foot wood frame home can yield 6,000 board feet of reusable lumber. That same house, when demolished, produces about 127 tons of debris.

View photos from the City of Portland's deconstruction trainings

Building wood back into buildings

After years of collaborating with experts, we’ve come to understand the best ways to increase the use of reused wood in building products. We consulted with salvage experts, reuse businesses, wood processors, manufacturers, builders, and designers, among others. The key is to create a facility to collect and process wood – a Salvaged Lumber Warehouse (SLW). Ideally, this SLW would be part of a larger circular ecopark with related businesses. The SLW would accept, process, grade (by size, strength, etc.),  inventory, and sell the wholesale clean lumber, known as salvaged lumber.

We're learning from similar partnerships and projects currently underway:

Advances in technology are helping bring this vision to life. For example, Urban Machine uses robotics and AI in their inline equipment to automate much of the wood processing, which has traditionally been a painstaking, manual process.

Oregon State University, Cornell University, and several European universities have also published promising results on the reuse of salvaged lumber in mass timber:

Example of salvaged CLT panel courtesy of Raphael Arbelaez and Oregon State University
Example of salvaged CLT panel courtesy of Raphael Arbelaez and Oregon State University

And finally, changes to building codes make it easier and less expensive to build with salvaged lumber by simplifying the grading and structural reuse of used sawn lumber. Similar to Oregon, the Washington State Building Code allows used sawn lumber to be structurally re-used for both residential projects (section R602.1.1.1) and commercial projects (section 2302.1.1.3). And building code appendices Y and Z allow local jurisdictions to adopt salvage and deconstruction requirements.

We’re currently collaborating with other jurisdictions to create a more sustainable, circular wood ecosystem in the region.

Resources

Building codes

Clean wood research

Deconstruction case studies and reports

Demonstration projects for wood collection and processing

Local businesses

Webinars and videos

Related topics

Re+ (zero waste)

Learn about our approach for reducing the amount of waste going to the landfill

Construction and Demolition (C&D)

Recycling and disposal options for C&D

Solid waste planning & monitoring

Find information on our solid waste reports, plans, and advisory committees
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