Box Gutter Overflow Design

Rainheads are an essential design element for buildings where internal box or trough gutters are used.

Box gutter overflow design. The gutters downpipes and overflow gdo calculator assists in developing a better understanding of the ncc volume two part 3 5 3 gutters and downpipes acceptable construction practice acp provisions. To use the gdo calculator enter information about the location roof design and types of overflow measures. The box gutter depth and the sump length are influenced by the size of the overflow. Holes through the splash guard and the gutter.

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. 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. Drill rivet holes for the gutter splash guard.

Making the box gutter wider will also reduce the box gutter depth. A rainhead or sump is a container located between the gutter and downpipe that aids the flow of water away from the roof. Overflow devices need to discharge to the atmosphere in such a way as to prevent damage to buildings and property. This is very important so that water will overflow externally to the building rather than flood into the roof cavity.

The hydraulic capacity of the overflow device must be no less than the design flow for the associated box gutter outlet. There will also be an overflow facility on the side or the end. A wider overflow needs less depth of overflow hence the box gutter depth will also be reduced. Overflow provisions rain shadow roof slopes how to find rainfall intensity how to calculate the area of any catchment how to find the hydraulic grade of charged pipes how to design box gutters using the code how to use the extra features of the dp calculator box gutters allowable width slope length other plumbing codes how to exceed the.

However a wider overflow may increase the length of the sump. A good box gutter design will have falls along its length together with sumps to collect water before it is fed into large downpipes.