Sizing Residential Gutters

Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.

Sizing residential gutters.

How to size gutters downspouts. If a roof s various drainage areas call for different size gutters go for the biggest one k style. You should have enough gutter downspouts to effectively handle the size of your entire gutter system. Adding additional downspouts will require less gutter and downspout volume resulting in smaller gutters downspouts.

However too large a gutter downspout can look unattractive. Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage. Once you are done deciding the correct size for your downspout depending upon the size of your gutter and the amount of rainfall in your area the next step shall be figuring out the kind of downspouts you want installed gpm stands for gallons per minute. Most downspouts are rectangular but they can also be round or square.

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. 5 inch 5 520 square feet. Then use the information below to see what size gutter you need. 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.

If a roof s various drainage areas call for different size gutters go for the biggest one k style. The gutter and downspout size required is highly dependent on the amount of gutter and the spacing of the downspouts. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website.

If frequent heavy showers occur where you live then a down spout with a bigger size would prove more suitable. Gutter downspout sizes are 3 to 6 inches. Half round and k style gutters are the two most common gutter types found on residential homes. 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. 6 inch 7 960 square feet. Doubling the number of downspouts halves the required capacity for each. Please lower the maximum spacing between downspouts to see this effect.

Each gutter style comes in two sizes and each has the capacity to. Size downspouts to fit the gutter.