Calculate How Many Downspouts Gutters Need

Aluminum is the most popular choice for gutter material because it s lightweight and durable.

Calculate how many downspouts gutters need.

3200 square feet of roof is calculated as 3200 600 5 33 rounding up you would need 6 2x3 downspouts or 3200 square feet of roof is calculated as 3200 1200 2 67 rounding up you would need 3 3x4 downspouts one 2x3 downspout will drain 600 sq. Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. In terms of material options most seamless gutters roughly 80 of all installs are made from aluminum. The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website.

Cost of aluminum gutters and downspouts. Use the chart below to figure out how many extra downspouts you need. So if you need to install 150 ln ft. One 3x4 downspout will drain 1200 sq.

Gutters come in many sizes. Not only can runoff from a roof ruin landscaping next to a building it may cause erosion that will damage the foundation. Large gutters can hold more water and may not need as many spouts. Rectangular 2 by 3 inches 600 square feet 3 by 4 inches 1 200.

Particularly wet climates could require better drainage systems than relatively dry climates rainy. Cost of vinyl gutters and downspouts. Size downspouts to fit the gutter. 2 by 3 inches 600 square feet.

3 by 4 inches 1 200 square. From time to time rain gutters wear out and must be replaced. As with gutters a downspout s capacity must match or exceed the expected runoff. Heavy rainstorms put a lot more pressure on gutters.

On average two hundred feet of gutter and 50 feet of downspout will cost approximately 2250. Prices range from 6 12 per linear foot for both gutters and downspouts. Smaller gutters may need extra downspouts to make up for their low volume. 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.

Use the chart below to figure out how many extra downspouts you need. Of gutters and downspouts you will be spending about 1 500 1 800. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. As with gutters a downspout s capacity must match or exceed the expected runoff.

Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. Doubling the number of downspouts halves the required capacity for each. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.