One 3x4 downspout will drain 1200 sq.
How many downspouts do i need on my gutter.
Most gutter installers add a downspout about every 20 or 30 feet of gutter although depending on the slope of your roof and the rooflines you may need more.
Gutters come in many sizes.
First you must consider how many downspouts you will need.
Large gutters can hold more water and may not need as many spouts.
Particularly wet climates could require better drainage systems than relatively dry climates rainy.
Smaller gutters may need extra downspouts to make up for their low volume.
If you want a neater look try burying the downspouts.
Size downspouts to fit the gutter.
Heavy rainstorms put a lot more pressure on gutters.
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.
3 by 4 inches 1 200 square.
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.
Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area.
Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.
Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area.
Use the chart below to figure out how many extra downspouts you need.
Buried or underground roof drainage downspout defects clogging overflowing holes corrosion leaks that cause wet basements or crawl areas proper installation of buried downspout extensions proper installation of french drains seepage pits at flat sites gutter downspout defects cause wet basements crawl areas questions answers about installing maintaining repairing buried roof.
But it a job many homeowners can do says mark weisman owner of mark s lawn and landscape in halethorpe maryland.
In areas with heavy rainfall your installer may also determine that for optimal flow you want downspouts on each end of a gutter run even if it.
Expect to pay more if the route is obstructed by tree roots or pavement.
You can hire a professional to dig a trench and bury a drain pipe for about 12 to 25 a foot.
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.
The gutter troughs and downspouts must be installed with this pitch in mind.
A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour.
How many downspouts do i need.
Rectangular 2 by 3 inches 600 square feet 3 by 4 inches 1 200.
If i could do it all over again i would have used 3x4 size downspouts the 2x3 size just can t handle these 100 year storms.
As with gutters a downspout s capacity must match or exceed the expected runoff.
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.
