Roof Area Per Downspout

Multiply the drainage area by the roof pitch factor and rainfall intensity to find out the adjusted square footage.

Roof area per downspout.

Size downspouts to fit the gutter. Rainfall intensity should always be checked with the local authorities. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. A large roof is going to move a lot of water which means the downspout locations may need to be adjust to compensate.

The roof plan area that is drained by each downspout is plan area 40 x 40 1600 sf. Given the area factor b in table 10c the design area is design area plan area x b 1600 x 1 05 1680 sf. From table 10a column b2 the area drained per square inch of downspout is 130 sf. The more roof surface above the gutters the more rainwater will be caught and funneled down into those gutters.

There are 5 easy steps to figure out how many drains your commercial roofing project will need. Gutters and downspouts are vulnerable for obstructions caused branches and leafs from surrounding trees and similar. A high slope moves water more quickly and if gutters have trouble dealing with a lot of. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.

Compatible with 2 in. Determine leader or pipe size. More product details close. The minimum downspout size is min.

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. 5 inch 5 520 square feet. Calculate total roof area. Welcome to gutter supply your online reference for gutters gutter machines gutter guards and accessories.

This durable downspout is maintenance free and has uv stabilizers to help prevent uv light degradation. Calculate the total roof area by multiplying its length by width. Then use the information below to see what size gutter you need. Come visit our selection of quality products.

The table is based on rainfall intensity 100 mm per hour 4 inches per hour. If a roof s various drainage areas call for different size gutters go for the biggest one k style. Metal or vinyl downspouts this versatile downspout has a lifetime guarantee. This wizard makes it easy to calculate the roof design area by providing various shape calculations and the calculation for vertical walls area per international plumbing code ipc.

Smacna s new downspout and gutter sizing calculator enables the user to manually enter the design area of the roof or use the design area wizard for the calculation.