Calculating Size Of Gutters

Downpipe and eaves gutter calculator valley gutters generic rain water outlets for flat roofs.

Calculating size of gutters.

Adding additional downspouts will require less gutter and downspout volume resulting in smaller gutters downspouts. If a roof s various drainage areas call for different size gutters go for the biggest one k style. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. 15 m is a practical maximum gutter length to be served by a downspout.

So for a roof that is 5 m long with a height of 4 m and the roof width is 8 m which makes the half roof width 4m we can calculate the effective roof area like this. Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage. 5m x 4m x 4 2 40 square metres. The gutter and downspout size required is highly dependent on the amount of gutter and the spacing of the downspouts.

In plastic k style 5 inch guttering will drain up to 5520 ft 6 inch up to 7960 ft. Calculate the area of a roof to work out how much guttering is required. Downspout sizes must not exceed the bottom width of the gutter. In response smacna s technical resources department has created a free downspout and gutter sizing calculator.

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

If a roof s various drainage areas call for different size gutters go for the biggest one k style. Size downspouts to fit the gutter. To limit the effects of thermal expansion in gutters 50 ft. Water pipe size calculator information video water pipe size calculators size every pipe in your project in seconds with just 3 clicks.

Now architects engineers designers and contractors can easily and accurately size downspouts and gutters according to. Simplified app for android phones. Multiply the surface area by the pitch factor to find the rain collection area for your roof and you can buy the right size guttering. 5 inch 5 520 square feet.

Then use the chart below to see what size gutter you need. In half round the capacities are 2500ft for 5 inch and for 6 inch 3840ft. Please lower the maximum spacing between downspouts to see this effect. 6 inch 7 960 square feet.

Doubling the number of downspouts halves the required capacity for each. The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.