Rain Gutter Slope Calculator

The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website.

Rain gutter slope calculator.

If the length of the gutter is 10 5 metres 35 feet the amount of slope required is 1 25 cm 1 4 inch multiplied by 1 metres 3 5 feet which when rounded up is 2 5 cm 1 inch. 15 m is a practical maximum gutter length to be served by a downspout. For example if you have 30 feet of guttering the calculation is 1 4 x 3 0 75 i e. We recommend using this calculator as a basic tool to begin determining the requirements for your drainage system however all information should be verified by hand prior to ordering or installing your gutter system.

3 select gutter type. Working out gutter slope as a general rule gutter slope is set at 1 4 inch per 10 feet of guttering. To limit the effects of thermal expansion in gutters 50 ft. This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end.

Now architects engineers designers and contractors can easily and accurately size downspouts and gutters according to the specifications in smacna s architectural sheet metal manual 7th edition 2012. Place the line spirit level on the string. Calculate the gutter slope by dividing the length of the gutter needed by 10. How to use the calculator 1 measure the length of your gutters along the eaves of your roof and plug in the number in the length field.