Lattice Floor Joists


All frame and truss optimized FRAMA machines can produce lattice trusses as standard.

The lattice truss is a cost-effective way of spanning larger areas and the truss depth can be varied to achieve different spans. Howick’s truss system offers a floor truss with greater spans and lighter weight than timber alternatives, and can be produced on a just in time basis. The FRAMA 4200 dedicated truss system allows for greater spans with thinner material than the equivalent joist made using a standard framing profile.

Indicative truss spans FRAMA 4200

Lattice Floor Joists
Depth (mm) Centres (mm) Section thickness (mm) Total load  Span (m)
225 400 1 2KN 7.09
250 400 1 2KN 7.47
300 400 1 2KN 8.19
225 600 1 2KN 5.79
250 600 1 2KN 6.10
300 600 1 2KN 6.46

Advantages of lattice joist system

  • Lightweight
  • Dimensionally accurate
  • Fits standard brackets and ties
  • Can be doubled up for longer spans
  • Riveted joint allows for bolted attachments
  • Howick's rivet is equivalent to 5 standard screws
  • The triple section connection (right) reduces the number of fixings and also increases the capacity of the joist
  • Very efficient use of steel* 

* The amount of steel used to construct a lattice floor joist only marginally increases as the joist depth becomes greater. Generally, only the extra height of the joist (x2) is the actual extra steel used and the number of fastenings actually reduces as less diagonal webs are used. This means very large gains in strength can be made, with no increase in weight or cost.