Box Gutter Overflow Design

Holes through the splash guard and the gutter.

Box gutter overflow design.

Rainhead overflow or specific box gutter overflow must be at least 30mm below the height of the back of the box gutter. A wider overflow needs less depth of overflow hence the box gutter depth will also be reduced. Making the box gutter wider will also reduce the box gutter depth. There are two categories of gutters.

There will also be an overflow facility on the side or the end. This effectively states that all box gutters must allow for 30mm of freeboard which is from the overflow point eg. You can find these precut gutter splash guards about 3 in brown and white aluminum at a home center but you could easily make your own out of aluminum or sheet metal and spray paint them to match your gutters. Sump with a side overflow device.

All domestic box gutters must be a minimum of 200mm wide and 75mm deep. Eaves and box gutters. However a wider overflow may increase the length of the sump. 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.

Failing to install appropriately designed box gutters and correctly sized and positioned overflow devices can lead to serious damage to buildings and contents especially in shed and flat house roof designs often resulting in hefty insurance claims which are a total burden. This is very important so that water will overflow externally to the building rather than flood into the roof cavity. Roofs may be constructed with or without gutters. 2015 3 7 4 layout.

Drill rivet holes for the gutter splash guard. Overflow box gutters must have independent overflow provision discharging to the atmosphere. The box gutter depth and the sump length are influenced by the size of the overflow. Box gutters sit within the façade or structure of the building.

Overflow devices need to discharge to the atmosphere in such a way as to prevent damage to buildings and property. Layout box gutters must. A good box gutter design will have falls along its length together with sumps to collect water before it is fed into large downpipes.