Calculate How Many Downspouts Gutters Need

Doubling the number of downspouts halves the required capacity for each.

Calculate how many downspouts gutters need.

Cost of vinyl gutters and downspouts. As with gutters a downspout s capacity must match or exceed the expected runoff. 2 by 3 inches 600 square feet. Size downspouts to fit the gutter.

So if you need to install 150 ln ft. Gutters come in many sizes. Rectangular 2 by 3 inches 600 square feet 3 by 4 inches 1 200. 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. As with gutters a downspout s capacity must match or exceed the expected runoff. The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website. Of gutters and downspouts you will be spending about 1 500 1 800.

Cost of aluminum gutters and downspouts. Use the chart below to figure out how many extra downspouts you need. 3 by 4 inches 1 200 square. 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.

From time to time rain gutters wear out and must be replaced. In terms of material options most seamless gutters roughly 80 of all installs are made from aluminum. Keeping gutters in good condition is more important than many people realize. 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.

Heavy rainstorms put a lot more pressure on gutters. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. One 3x4 downspout will drain 1200 sq. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour.

Elbows miters end caps gutter outlets gutter wedges gutter offsets coil sheet goods gutter hangers downspout brackets gutter flashings gutter fasteners conductor leader heads aluminum soffit trim gutter decorations downspout guards accessories paint sealant solder polish tile. Typically professionally installed aluminum seamless gutters cost 10 12 per linear foot. Aluminum is the most popular choice for gutter material because it s lightweight and durable. Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area.

Smaller gutters may need extra downspouts to make up for their low volume. Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. Particularly wet climates could require better drainage systems than relatively dry climates rainy.