Downspout installation: enough outlets, the right size, and water sent where your yard can take it
Every gallon your roof sheds leaves the house through a downspout. We add outlets where one corner carries too much, fit 3x4 pipe under big roofs, replace crushed sections and point the water away from the wall.
The roof seen from above. In a one-inch rain the whole footprint sheds about 1,246 gallons.
Two more outlets halfway along the long sides. Each corner now takes a third less water.
How many downspouts does my house need?
Count one outlet for every 35 to 40 feet of gutter, then add one wherever a valley drops two slopes of water into a single section. On a run longer than 40 feet we pitch the gutter from the middle out to an outlet at each end, so the water never travels the full length. The numbers come from our article on gutter pitch and downspout placement.
Size goes by the roof area that drains into each pipe. The two openings below are drawn to the same scale.
2x3 inch
6 square inches of opening. Handles up to about 600 sq ft of roof.
Goes with a 5-inch gutter on most homes.
3x4 inch
12 square inches, twice the opening. Up to about 1,200 sq ft.
Goes with a 6-inch gutter under large, steep or tree-covered roofs.
Should I switch to 3x4 downspouts? If water sheets over the front of a clean gutter in a hard rain, or maple seeds plug the bottom elbow every spring, yes. Our guide to 5-inch against 6-inch gutters walks through the bigger system.
What we change on the downspouts you already have
Most of our downspout work is on houses whose gutters are fine. These are the six situations we find most, and what goes up in their place.
A gutter that sags, leaks at the corners or has lost its pitch is fixed first. That work is on our gutter repair page, and a full new system on seamless gutters.
How far from the house the water has to land
The strip starts at your foundation wall. Each mark is a published distance for where a downspout should discharge on the surface, and the ground past the outlet must fall away from the house.
3 ft, City of Chicago
The shortest the city's downspout disconnection guide accepts for an extension.
5 ft, U.S. Department of Energy
The surface distance in its building guide, and the length we aim for on a typical lot.
Your village may cap it
Mount Prospect allows the outlet no more than 5 feet from the foundation and no closer than 5 feet to a lot line.
Codes differ by village, so we check yours before an extension goes on. The rules, the gallons and the yard-by-yard choices are in our guide on where downspouts should drain.
What downspouts cost, worked from our published rate
We price downspouts by the foot at about the same rate as seamless gutter. Here is a two-story house with one downspout at each corner.
How much does downspout installation cost on your house? It depends on the stories, the number of outlets and the extensions. The rate comes from our gutter cost per foot guide. You get a written price after we measure.
Downspouts we've put up
After hail: which dented downspout matters
Soft aluminum dents at hail sizes too small to bruise a shingle, so dented downspouts are some of the first evidence that a storm reached your house. Photograph them and leave them alone until an adjuster has seen them.
Upper face crushed
Hail hits the surfaces that face up and into the wind. A visibly pinched pipe slows how fast the gutter empties, so it counts as functional damage.
Bottom elbow dented
Waist height, one or two dents, nothing else marked on the house. That was a mower or a ladder, and it's a repair rather than a storm claim.
What Illinois law lets a roofer do
Under Illinois law a roofer may not negotiate a claim for you. We photograph every damaged run, measure it and write a code-compliant estimate. Our partner State Adjusting Services, a licensed Illinois public adjuster, can represent you on the claim. More in our article on hail damage to gutters and downspouts and on the storm and insurance page.
Who comes out
Our own crews leave from Lincolnshire. We're a family business licensed in Illinois as a roofer under number 104.018671, working in the north and northwest suburbs such as Buffalo Grove, Northbrook and Arlington Heights.
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Call during these hours
7 AM to 7 PM on weekdays, 9 AM to 5 PM on Saturday and Sunday.
Questions about downspouts
How many downspouts does my house need?
Plan on one for every 35 to 40 feet of gutter, plus one at any section a valley drains into. A 2x3 pipe handles about 600 square feet of roof and a 3x4 about 1,200, so a big or steep slope may need two outlets instead of one.
Should I switch to 3x4 downspouts?
Switch when the gutter overflows in a hard rain while it's clean, when seeds plug the elbows every spring, or when you move to 6-inch gutter. A 3x4 has twice the opening of a 2x3, so debris and ice have more pipe to block.
How far should a downspout extension go from the house?
Aim for 5 feet on ground that slopes away, the U.S. Department of Energy figure, and never less than the 3 feet the City of Chicago asks for. Some villages cap the distance, Mount Prospect at 5 feet, so the local code is checked first.
How much does downspout installation cost?
At our published $6 to $14 a foot installed, four 20-foot downspouts on a two-story house come to about $480 to $1,120. Extensions, extra outlets and the height of the house move the final number, which you get in writing after we measure.
Want this looked at?
We inspect for free, document what we find and prepare a code-compliant estimate you can hand to your insurer. Our partner, a licensed public adjuster, State Adjusting Services, can represent you on the claim.
Call (866) 992-2982. Free Inspection