Roof Square Footage Per Downspout

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

Roof square footage per downspout.

Gutters come in a wide range of materials the cost depends on which you choose. It doesn t take many sticks leaves or needles to impede the proper flow of water in the eavestrough. A high slope moves water more quickly and if gutters have trouble dealing with a lot of water in a short period of time an extra downspout can alleviate that issue. A large roof is going to move a lot of water which means the downspout locations may need to be adjust to compensate.

To do that simply multiply drainage area calculated earlier by roof pitch factor and rainfall intensity. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. Intensity lasting calculated roof area intensity lasting calculated roof area 5 minutes drained per 5 minutes drained per downspout area downspout area in hr mm hr sq ft sq m in hr mm hr sq ft sq m sq in 100 sq mm sq in 100 sq mm 7 4 187 160 2 30 10 4 265 110 1 70 7 1 181 170 2 40 9 9 251 120 1 70 1 8 46 660 9 50 3 1 77 390 5 70. For a 5 inch k style gutter the square footage should be up to 5 500 sq ft and for a 6 inch k style gutter the square footage should be upto 7 900 sq ft.

For a 2 400 square foot roof you can expect to spend 792 to 1 704. Size downspouts to fit the gutter. For the vast majority of rains gutter and downspouts sizes considerably less than recommended will do the job. A house in chicago has a roof whose actual drainage area is 1 000 square feet.

One foot of 6 k style gutters holds 2 0 gallons of water. Multiplying that number by the local maximum rainfall intensity 6 8 inches per hour yields an adjusted square footage of 7 480 square feet. There is a range of different solutions for roofing underlay some are tacked or stapled while others are self adhesive ranging in price from 0 18 to 0 49 per square foot for materials only. 8 inches and you have an 8 in 12 pitch.

Therefore this roof should be equipped with 6 inch k style gutters. Multiplying that number by the local maximum rainfall intensity 6 8 inches per hour yields an adjusted square footage of 7 480 square feet. Pitch measurement method 2. Metal gutters vary in price from 6 to 12 for aluminum and 9 to 20 for steel to 25 or more for high end copper.

Vinyl gutters cost 2 to 5 per linear foot. One foot of 5 k style gutters holds 1 2 gallons of water. Two hundred feet of gutter can cost anywhere between 660 and 4 500. If this distance measures 4 inches you have a 4 in 12 pitch.

The 6 in 12 pitch factor 1 1 multiplied by 1 000 yields an effective area of 1 100 square feet. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed. On a ladder beside the roof place the level a foot or so up the roof hold it level and measure from the 12 inch mark on the level s bottom straight down to the roof.