An introduction to open web joists

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Open Web Joists are parallel chord trusses made from strength-graded timber joined together with either timber of metal webs. The resulting joist combines the lightness of timber with the structural qualities of the metal webs or plates, to produce a factory made precision-engineered component that is lightweight, strong and versatile.

This data sheet from the Trussed Rafter Association explains the benefits of open web joists which make them ideally suited to modern methods of construction. It also details how, despite being designed for flooring, Open Web Joists can be used for a variety of other commercial, domestic and industrial structural applications.


  • Description
  • Services
  • Practical benefits
  • Applications
  • Sizes
  • Support details
  • Technical Approvals
  • Site handling & storage
  • Do's and Dont's

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