Timber Frame Residence: Timber Frame Structural Engineering in Oregon

Location: Eugene, Oregon
Client/Owner: Our client, the owner
Partners: Six Degrees Construction (builder)
Year: 2005
Size/scale: Two-story home with an interior timber frame of four bents
JBE services: Structural design of the timber frame, including member sizing and joinery checks; foundations, floor framing and the lateral system; special inspection of the joinery and structural observation during the raising
Sector: Residential

Timber frame residence structural engineering project, Oregon — photo 1

The challenge

This two-story single family home is built around an elegant timber frame, and its frame is left exposed. The frame uses traditional mortise-and-tenon joinery, so the joints are on show as well as working hard. Every joint has to carry its load and look right. Timber floor beams carry tongue-and-groove decking at the second floor, and timber rafters run over timber purlins at the roof.

Project photos

What we did

We sized every member of the timber frame and checked its joinery joint by joint. Where traditional joinery wasn’t strong enough on its own, we added conventional metal hardware, and only there. The timber frame carries the home’s gravity loads. A conventional stud wall around the outside carries wind and earthquake loads, which let the frame stay open and uncluttered inside. We also designed the footings and foundation, the first-floor framing and the shear walls.

The City of Eugene required special inspection of the joinery and structural observation of the frame. We measured the bents and members before they went up, observed the bents as Six Degrees Construction assembled them for raising in September 2005, made periodic site visits until the frame was complete, and checked late changes to the frame and to the shear walls around the windows.

The result

An elegant timber frame home in Eugene, completed in 2005–2006, with its structure on display. It’s the kind of timber frame structural engineering in Oregon where the engineering is part of the architecture.