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Trefethen Historic Building

Napa, CA
  • Bldg system

    Mass Timber

  • No. Of Stories


  • Sq. footage


A 2014 earthquake left the historic Trefethen winery in a precarious tilt when the second and third story of the three-story structure shifted nearly four feet. Because it was built in 1886 and listed on the National Register of Historic Places, the Trefethen family decided to undertake an extensive restoration. Crews removed and repaired the exterior redwood siding, then strengthened and straightened the internal wood structure by adding two bolted-connection steel moment frames, aligned with the original timber posts. Where possible, they repaired damaged wood framing members by injecting color-matched wood epoxy. They also installed new connectors between existing beams, posts and foundations, and added bolted steel side plates at floor beams for additional strength. By doing all this, they were able to preserve the majestic, vaulted spaces in the tasting room and barrel storage area, while still showcasing the original timber construction. Next, they installed new exterior shear walls and re-clad the building using the original redwood siding. As final tribute, the Trefethen family left a single ‘Remembrance Post’ in its deflected state to illustrate the magnitude of the earthquake withstood by the structure.

  • Construction Type:


  • Building Type:

    Assembly (Worship, Restaurant, Theater)

  • Material Types:

    Mass Timber, Hybrid (wood with steel or concrete)

Companies Involved:
  • Taylor Lombardo Architects


  • ZFA Structural Engineers

    Structural Engineer

  • Facility Development Company

    General Contractor

Individuals Involved:
  • Tom Taylor


  • Marianne Wilson

    Structural Engineer

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