Calculate Rainwater Gutter Size

If gutters don t slope water gathers in them.

Calculate rainwater gutter size.

Downspout sizes must not exceed the bottom width of the gutter. Proper gutter and downspout sizing rainfall intensity downspout capacity. To determine the design area multiply the plan area by the factor in b column these areas are then divided by the proper factor given in table 1 2 thus obtaining the required area in square inches square mm for each downspout. To determine the design area for a pitched roof table 1 1 is used.

Roof often leads to oversizing of gutters downspouts and drains. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. Doubling the number of downspouts halves the required capacity for each.

Box gutter with rain water head at end of box gutter. Simplified suitable for flattish roofs with little or no vertical faces or steep roofs draining to one side of box gutter only or any roof if you are in a hurry and make the necessary allowances for all catchments. From table 1 3 select the downspout. Welcome to gutter supply your online reference for gutters gutter machines gutter guards and accessories.

The gutter slope also called the pitch is the amount the gutter tilts down to let rainwater flow out of it. Subtracting 3 4 for under the roof edge and 1 8 outside edge allowance this is the width that is available for the rainwater to enter the gutter total width of a flat piece of building material maximum total gutter drop before any downspout this assumes 4 7 per hour maximum rain intensity. Come visit our selection of quality products. Boasting considerable experience spanning over 25 years gutter masters company has operated on different buildings scenarios and designs with success at each turn.

If gutters slope too severely they don t hold water and water could splash over the sides in heavy rain. To limit the effects of thermal expansion in gutters 50 ft. Cost calculator rain gutter installation calculator. However in areas like san diego orange county and other parts of southern california we are often praying for rain and do not seem to get enough rainfall to cause builders to automatically add a.

15 m is a practical maximum gutter length to be served by a downspout. To determine the design area multiply the plan area by the factor in b column these areas are then divided by the proper factor given in table 1 2 thus obtaining the required area in square inches. The amount of collected water increases until it spills over the sides of the gutter.