Gutter And Downspout Design Calculations

Table 1 1 design areas for pitched roofs pitch in ft.

Gutter and downspout design calculations.

This spread sheet will help you calculate the gutter width and maximum distance between downspouts based on your maximum rainfall roof area and style of gutter. Downspout sizes must not exceed the bottom width of the gutter. Adding additional sections of gutter reduces the length of each section and will reduce the gutter size. To limit the effects of thermal expansion in gutters 50 ft.

There are two major factors to consider when deciding a gutter design. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. Doubling the number of downspouts halves the required capacity for each. Calculations are based on level gutter capacity as experimentally determined by the national institute of standards and technology nist.

The gutter and downspout size requirement depends upon the number of sections and length of the gutter sections as well as the number of downspouts. Size downspouts to fit the gutter. With 1 gpm 0 063 l s flow rate. This wizard makes it easy to calculate the roof design area by providing various shape calculations and the calculation for vertical walls area per international plumbing code ipc.

Downspouts and gutters are sized in relation to rainfall on this basis. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. Experience has taught that use of the true area of a pitched roof often leads to oversizing of gutters downspouts and drains. Roof in the calculation of a drainage system.

The first is to make it wide and deep enough to collect all of the rainwater during the hardest rainfall.