For commercial projects the minimum allowable width is 300mm.
Box gutter sump regulations.
The regulations require that guttering has allowances for water to overflow gutters in a way that does not cause water to flow back into the structure.
Must have a constant slope between 1 40 and 1 200.
Sumps are to be appropriately sized in accordance with as nzs 3500 3 with a minimum length of 400 mm and when fitted with a high capacity overflow device with a depth of not less than 150 mm when either one or two box gutters enter the sump.
For the associated box gutter outlet.
Read more about compliant guttering options what does it mean for installers.
Experiment with this figure to get the depth of box gutter you require.
Sump with a side overflow device sumps do require an increase in the depth of flow in the box gutter and gutters are to be fitted with either.
Sides must be vertical.
The minimum size of a sump is 400mm x 200mm minimum width of box gutter and 150mm deep.
Down pipe must be vertical from sump not to the side minimum sump length is 400mm.
Have a minimum depth of 75mm at the high end.
Have a minimum width of 300mm for commercial installations 200mm for domestic installations.
Have a sole width which is not reduced discharge at the downstream end without.
Trial box gutter width the minimum width allowed for domestic projects is 200mm.
However any width can be entered.
Vertical faces enter the full vertical face area.
Sizes the depth shown of the box gutter is the depth at the upstream end.
Overflow devices need to discharge to the atmosphere in such a way as to prevent damage to buildings and property.