Trial box gutter width the minimum width allowed for domestic projects is 200mm.
Box gutter overflow requirements.
Hang the gutter lower the top of the bead must be 20mm below the top of the fascia to allow water to overflow safely over the bead.
Use a 10mm spacer this creates a gap behind the gutter so water can overflow freely.
Have a minimum width of 300mm for commercial installations 200mm for domestic installations.
Box gutters must be straight no bends.
Have a minimum depth of 75mm at the high end.
This effectively states that all box gutters must allow for 30mm of freeboard which is from the overflow point eg.
Sides must be vertical.
The vba has provided several options for plumbers to make an installation compliant.
The minimum width allowed for domestic projects is 200mm.
For commercial projects the minimum allowable width is 300mm.
The hydraulic capacity of the overflow device must be no less than the design flow for the associated box gutter outlet.
However any width can be entered.
If draining to a sump with a vertical overflow somewhere along the box gutter use this calculator.
Code box gutter requirements.
Rainhead overflow or specific box gutter overflow must be at least 30mm below the height of the back of the box gutter.
Overflow devices need to discharge to the atmosphere in such a way as.
For commercial projects the minimum allowable width is 300mm.