How Many Downspouts Are Needed For Gutters

For most homes this means installing spouts at either end of a gutter section.

How many downspouts are needed for gutters.

Use the chart below to figure out how many extra downspouts you need. The typical recommendation is one downspout for every 20 to 30 feet of gutters. 2 by 3 inches 600 square feet. How many downspout installations should your gutters have.

The next factor to take into account is the pitch of your roof because the pitch will cause water to flow in a certain direction. Doubling the number of downspouts halves the required capacity for each. Size downspouts to fit the gutter. The gutter troughs and downspouts must be installed with this pitch in mind so that water flows down instead of remaining stagnant in the gutter trough.

Rectangular 2 by 3 inches 600 square feet 3 by 4 inches 1 200 square feet. Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area. A general rule of thumb is one downspout per 20 feet of guttering but more may be necessary depending on the local weather the size of the drainage area and the design of the gutter system. 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 feet. If we have to sum it up in a single rule gutters need a downspout around every 30 to 40 feet. 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.

First you must consider how many downspouts you will need. As with gutters a downspout s capacity must match or exceed the expected runoff. Poorly designed or installed gutters and downspouts can cause rainwater to pool around the base of the home or back up into the gutters.