Calculate How Many Downspouts Gutters Need

As with gutters a downspout s capacity must match or exceed the expected runoff.

Calculate how many downspouts gutters need.

Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. 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. 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. Large gutters can hold more water and may not need as many spouts.

Use the chart below to figure out how many extra downspouts you need. Aluminum is the most popular choice for gutter material because it s lightweight and durable. Use the chart below to figure out how many extra downspouts you need. Not only can runoff from a roof ruin landscaping next to a building it may cause erosion that will damage the foundation.

Typically professionally installed aluminum seamless gutters cost 10 12 per linear foot. On average two hundred feet of gutter and 50 feet of downspout will cost approximately 2250. Doubling the number of downspouts halves the required capacity for each. Cost of aluminum gutters and downspouts.

In terms of material options most seamless gutters roughly 80 of all installs are made from aluminum. One 3x4 downspout will drain 1200 sq. Smaller gutters may need extra downspouts to make up for their low volume. Heavy rainstorms put a lot more pressure on gutters.

So if you need to install 150 ln ft. Size downspouts to fit the gutter. Cost of vinyl gutters and downspouts. Of gutters and downspouts you will be spending about 1 500 1 800.

The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. 3 by 4 inches 1 200 square. From time to time rain gutters wear out and must be replaced.

Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. As with gutters a downspout s capacity must match or exceed the expected runoff. 2 by 3 inches 600 square feet. Prices range from 6 12 per linear foot for both gutters and downspouts.

Gutters come in many sizes. Keeping gutters in good condition is more important than many people realize. Particularly wet climates could require better drainage systems than relatively dry climates rainy.