Rain Water Gutter Size

Five inch k style gutters or 6 inch half rounds the most common residential sizes are able to handle the rainfall on most houses in most parts of the country.

Rain water gutter size.

5 inch 5 520 square feet. Then use the chart below to see what size gutter you need. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. You should have enough gutter downspouts to effectively handle the size of your entire gutter system.

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. The larger a gutter downspout the more water it can drain quickly. 6 inch 7 960 square feet. Doubling the number of downspouts halves the required capacity for each.

See photos below most residential gutters will measure approximately 5 inches across the top with the actual opening being approximately 4 5 inches. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage. Also the gutter width in relation to height may also be adjusted.

If a roof s various drainage areas call for different size gutters go for the biggest one k style. However too large a gutter downspout can look unattractive. Size downspouts to fit the gutter. Most downspouts are rectangular but they can also be round or square.

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. 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. Use this handy guide to make sure your rain collection is up to the task during even the heaviest storm. Adding additional sections of gutter reduces the length of each section and will reduce the gutter size.