Sub-floor framing - Floor joists

• Introduction
• Position
• Spacing
• Span
• Notching
• Joints
• Supporting fitted floorboards
• Supporting platform floors
• Deep floor joists
• Size and grade

Deep floor joists

Deep floor joists are those where the joist height exceeds four times its width.

Deep floor joists must be restrained from rolling over. They require blocking between the joist spacings. This can be achieved by:

• providing a continuous trimming joist to the ends of the joists immediately over the external bearer
  or
• solid blocking between the outer pairs of joists and between intermediate pairs at not more than 1.8 metre centres. Where span exceeds 3 metres additional mid-span blocking at 1.8 metre spacings may also be required.