Notches and holes
Notches
- Should only be made in the top edge of the joist
- Should be no deeper than 0.125 times the depth of the joists.
- Should be no closer to the support than 0.07 times the span and no further away than 0.25 times the span.
Maximum notch depth
Joist depth | Notch depth |
---|---|
125mm | 15mm |
150mm | 18mm |
175mm | 21mm |
200mm | 25mm |
225mm | 28mm |
Holes
- Should only be drilled on the centre line of the joist.
- Should have a diameter no greater than 0.25 times the depth of the joist.
- Should be no closer together than 3 times the larger diameter.
- Should be no closer to the support than 0.25 times the span and no further away than 0.4 times the span.
- If the above requirements cannot be met within the limitation shown, then increase the joist depth by the depth of notches or diameter of holes.
Last updated: Wednesday, 5 October, 2022.