Working for a safe, affordable, vibrant, innovative, and interconnected city.
Learn More Home Page This Department
Link to Seattle Department of Planning and Development home page DEPARTMENT OF PLANNING & DEVELOPMENT

Cross-Laminated Timber

Evaluating whether the Seattle Building Code should allow more height for buildings designed with cross-laminated timber.

What is Happening Now?

Our Seattle Building Code currently limits buildings made of wood products to no more than 85 feet in height and no more than 6 stories (depending on use of the building). With the aid of the Construction Codes Advisory Board’s Innovation Advisory Committee, we are deciding whether to allow bigger buildings built of cross-laminated timber (CLT).

CLT is an engineered product made of sheets of boards placed in layers perpendicular to one another in a manner similar to plywood. However, unlike plywood, CLT is made of thick layers of lumber with enhanced structural and fire-resistive performance.

Large CLT buildings have been built in other parts of the world. The Graphite Apartments in London is a nine-story CLT building, and a 10-story residential building, Forté is nearing completion in Melbourne, Australia.

Proposed Benefits

  • Carbon negative construction
  • Sustains local materials and industries
  • Reduces construction time
  • Cost competitive with concrete and steel
  • Clean and quiet construction process
  • Ideal for tight urban sites

The End Result

We will continue further evaluation to determine if the Seattle Building Code should be modified to allow buildings designed with cross-laminated timber to achieve greater height.

Meetings & Events


 Ask Us

Kathleen Petrie
Sustainable Codes Analyst
(206) 615-0541

icoFacebook24x icoTwitter24x