Rain Water Gutter Size

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.

Rain water gutter size. But houses with big steep roofs or those located in climates prone to heavy downpours may need wider gutters and extra downspouts to keep rainwater from overflowing. Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage. The larger a gutter downspout the more water it can drain quickly. You should have enough gutter downspouts to effectively handle the size of your entire gutter system.

Then use the chart below to see what size gutter you need. If a roof s various drainage areas call for different size gutters go for the biggest one k style. Also the gutter width in relation to height may also be adjusted. Adding additional sections of gutter reduces the length of each section and will reduce the gutter size.

Size downspouts to fit the gutter. Unless special provisions are made for flexibility in downspouts rain gutters and their support systems gutters should expand away from downspouts and downspouts should not be located near gutter expansion joints. 6 inch 7 960 square feet. However too large a gutter downspout can look unattractive.

5 inch 5 520 square feet. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. Use this handy guide to make sure your rain collection is up to the task during even the heaviest storm. Measure your gutter across the top from the back where the gutter meets the home to the outer edge.

Most downspouts are rectangular but they can also be round or square. To limit the effects of thermal expansion in gutters 50 ft 15 3 m is a practical maximum length of gutter to be served by a downspout. Doubling the number of downspouts halves the required capacity for each. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.