Rain Water Gutter Size

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.

Rain water gutter size.

The larger a gutter downspout the more water it can drain quickly. 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. Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage. See photos below most residential gutters will measure approximately 5 inches across the top with the actual opening being approximately 4 5 inches.

6 inch 7 960 square feet. 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. Measure your gutter across the top from the back where the gutter meets the home to the outer edge. Adding additional sections of gutter reduces the length of each section and will reduce the gutter size.

You should have enough gutter downspouts to effectively handle the size of your entire gutter system. If a roof s various drainage areas call for different size gutters go for the biggest one k style. 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.

However too large a gutter downspout can look unattractive. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. Use this handy guide to make sure your rain collection is up to the task during even the heaviest storm. Then use the chart below to see what size gutter you need.

Doubling the number of downspouts halves the required capacity for each. Also the gutter width in relation to height may also be adjusted. Most downspouts are rectangular but they can also be round or square. Size downspouts to fit the gutter.