Sizing Residential Gutters

A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour.

Sizing residential gutters.

You should have enough gutter downspouts to effectively handle the size of your entire gutter system. Size downspouts to fit the gutter. Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage. Gutter downspout sizes are 3 to 6 inches.

Doubling the number of downspouts halves the required capacity for each. 5 inch 5 520 square feet. Then use the chart below to see what size gutter you need. The larger a gutter downspout the more water it can drain quickly.

Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage. Then use the information below to see what size gutter you need. The gutter and downspout size required is highly dependent on the amount of gutter and the spacing of the downspouts. How to size gutters downspouts.

5 inch 5 520 square feet. Please lower the maximum spacing between downspouts to see this effect. 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.

6 inch 7 960 square feet. If frequent heavy showers occur where you live then a down spout with a bigger size would prove more suitable. Half round and k style gutters are the two most common gutter types found on residential homes. Each gutter style comes in two sizes and each has the capacity to.

The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website. Residential sizing samples are available to check the optimal fit but in most cases the 5 half round gutter requires standard gutterbrush for 5 gutters 4 25 dia while the 6 half round gutter requires oversized gutterbrush for 6 gutters 5 25 dia. If a roof s various drainage areas call for different size gutters go for the biggest one k style. 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.

By clicking below i m interested in having your products installed on my home and would like to learn more about gutter helmet by harry helmet products and sales in the future i understand you use an autodialing phone and text system and my consent is not required to obtain a free estimate i can call 888 543 5638 instead. Most downspouts are rectangular but they can also be round or square.