Overflow devices need to discharge to the atmosphere in such a way as to prevent damage to buildings and property.
Box gutter sump installation.
The side with the maximum flow is used to size the box gutter.
The total flow is used to size the sump and overflow.
Establish the sump location this should be the lowest point in the box gutter.
With building design being so restrictive on space these days this is the area where designers must think about how the roofing contractor will make the box gutter comply.
If the box gutter has no overflow provisions this causes a waterfall over the sides of the box gutter typically running down the walls.
This free online box gutter calculator will calculate the size of box gutters and sumps with a side overflow in accordance with the australian plumbing code as nzs 3500 3 2003 part 3 storm water drainage.
Layout box gutters must.
If you have any questions about the vid.
Support the entire weight of the gutter and sumps when full of water as well as a trafficable load at any point in the gutter and sumps.
At this stage plan the connection to the downpipe.
Rainheads are an essential design element for buildings where internal box or trough gutters are used.
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.
A rainhead or sump is a container located between the gutter and downpipe that aids the flow of water away from the roof.
Each box gutter run must discharge independently to ether a sump or directly out of the building without changing the size of the gutter or changing direction.
The outlet of the box gutter may be blocked by debris or the box gutter outlet simply cannot discharge the water fast enough.
Refer to hints for box gutter design marking and cutting the sump spigot mark cut sump hole dress the cut out to neatly fit to the sump decide on the position of the spigot mark and cut the hole.
It sounds like you have an overflow situation.
Outlets box gutter outlets must discharge through either a rainhead or sump.