Timber Wave at the University of Washington

The Barry Onouye Endowed Studio in the Department of Architecture at the University of Washington explores the intersection of architecture and structural engineering.

In spring 2025, graduate architecture students in this studio designed a reciprocal timber pavilion, titled the Timber Wave.  Made entirely of interlocking 'W' shaped modules of dimensional lumber, this pavilion highlights the strength and beauty of Washington-grown timber.  Led by Associate Professor Tyler Sprague, and visiting instructors Leif Johnson & Marne Zahner of StructureCraft, the design was inspired by a Leonardo da Vinci sketch to be self-supporting at all stages of construction - requiring no scaffolding or falsework.  

From the beginning, the studio worked with a donated stock of 8-foot long 2x3, 2x4, 2x6 Doulgas Fir and Hemlock lumber.  This material was facilitated by the Sustainable Forestry Initiative, Washington Implementation Committee, and provided by Sierra Pacific & Hampton Family Forests.  The studio prioritized making maximum use of Washington-state grown timber to create a structural pavilion and maximize re-use potential.

After individual case studies and early concept work, students collectively pursued a modular reciprocal structure – one where individual modules both support and are supported-by the adjacent modules.  This structure takes advantage of the bending capacity of the timber during construction, but results in a largely compressive, form-active vault.  The ‘W’ module required minimal fabrication and provided in-plane dimensional depth and stability.  Four 2x4 diagonals and one 2x6 cross member were fastened together with metal screws, retaining their entire length and possibility for screws to be reversed. Minimal notching at the ends of the 2x4s ensured good bearing surfaces between adjacent modules and provided construction alignment guides.

Through an over-under, interlacing construction process, a single, reciprocal arch could grow in size by simply lifting one end and adding an additional module. At this scale, the end of each arch (one module wide) could be easily lifted by 2-3 people without assistance.  Each arch began at the top of a pre-existing stem wall and gradually grew to span over 28’ and rise over 9’ tall.  Five rhythmic arches combine to create the vaulted pavilion, spliced together to engage shell behavior and enable an interior opening to the sky.  The wall base condition become an opportunity for seating, and the studio designed a hanging bench interconnected to the pavilion’s base.  The lower base condition fit into an existing gutter, resolving outward thrust with minimal timber elements.

The timber arches merge into a continuous wooden wave, an architectural ripple that invites exploration, curiosity, and tactile engagement. At its core, a central void allows close inspection of the structural joinery, while adjacent scaled-down modules offer visitors the opportunity to build and disassemble a miniature version of the structure themselves.

Instructors:

Tyler Sprague, Associate Professor
Leif Johnson, StructureCraft
Marne Zahner, StructureCraft

Students:

Bradlee Anderson
Jeremy Arena
Jonathan Bechtol
Aaron Best
Garrett Dorn
Brannon Ellinwood
Bearach Miwanti-Minter
Marco Nielsen
Salar Salahshoor
Zoe Willig
Bixuan Zou

Photographer Credits:

Tyler Sprague, University of Washington
Alex Blair, College of Built Environments, University of Washington
Garrett Dorn, University of Washington