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Thurston County Building Codes

Truss Design Drawings and Specifications

trussIf your building project will use truss-framed roof or floor systems, you are required to submit engineered, stamped truss design drawings and specifications along with your building permit application.

Truss design drawings and specifications must include, at a minimum:

  • Slope or depth, span and spacing.
  • Location of all joints.
  • Required bearing widths.
  • Design loads as applicable.
    • Top chord live load (including snow loads)
    • Top chord dead load.
    • Bottom chord live load.
    • Bottom chord dead load.
    • Concentrated loads and their points of application.
    • Controlling wind and earthquake loads.
  • Adjustments to lumber and joint connector design values for conditions of use.
  • Each reaction force and direction.
  • Joint connector type and description (e.g., size, thickness or gauge) and the dimensioned location of each joint connector except where symmetrically located relative to the joint interface.
  • Lumber size, species and grade for each member.
  • Connection requirements for:
    • Truss to truss girder.
    • Truss ply to ply.
    • Field splices.
  • Calculated deflection ratio and/or maximum description for live and total load.
  • Maximum axial compression forces in the truss members to enable the building designer to design the size, connections and anchorage of the permanent continuous lateral bracing. Forces shall be shown on the truss design drawing or on supplemental documents.
  • Required permanent truss member bracing location.


Contact Us

Questions can be emailed to staff at the email addresses below. Just click on the e-mail address and send your questions. We would be glad to help answer any question you have about your construction plans.

Commercial and Residential plan review: Available Monday through Friday, 8 a.m. - 4:00 p.m. at the Building Development Center.  Tim Rubert: tim.rubert@co.thurston.wa.us; Rowland Zoller: rowland.zoller@co.thurston.wa.us; (360) 754-3355 ext. 7289.

Building inspections: Available Monday through Friday, 7 a.m. - 8 a.m. at (360) 786-5489.  Requests for permit extensions: permit@co.thurston.wa.us.  To request an extension of a building permit, submit a request prior to the expiration of the building permit.  Click here for the building permit extension request form.

Fire marshal and fire annual safety inspection: Bobby May: bobby.may@co.thurston.wa.us

All other building or fire code questions can be directed to the Building Services Supervisor, Chris Edmark: chris.edmark@co.thurston.wa.us or by calling (360) 786-5466.



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