Gutter Downspout Installation: A Complete Guide for Homeowners
Ask most people about their gutters and they'll talk about the gutters. Hardly anyone brings up the downspouts, but around metro Atlanta that's where we find a lot of the trouble.
When a gutter overflows, the gutter itself is usually fine. Most of the time the downspout just can't let water out as fast as the roof is pouring it in.
How Downspouts Get Sized Against Roof Area
Downspout size is about how much roof drains into it. How big the house is doesn't really matter.
On homes you'll mostly see 2x3 and 3x4. The 3x4 has about twice the opening, so it empties a gutter a lot faster.
2x3 downspouts show up on a lot of existing homes, and on bigger or steeper roofs they can have a hard time keeping up. Over a small
section of roof, they're usually fine.
Steep roofs shed water faster than flatter ones. So two houses with the same roof area might still need different downspouts.
Want to figure out your own house? Our guide on how many downspouts a roofline needs walks through it.
Where Downspouts Should Be Placed
The idea is simple. Shorter trip inside the gutter, less chance of a spill.
Say you've got a long gutter with one downspout way down at the end. Rain from the far end has to go the whole length, so that's the end that fills first and spills.
Add a second downspout and you cut the trip about in half. On a long ranch house that's often a better fix than a bigger gutter.
We also like to look at inside corners. Water comes in from two sides there and slows down, so a downspout close by tends to do better than one farther along.
And it has to empty somewhere that makes sense. The perfect spot on paper is no good if it drains onto your front walk or right at the foundation.
What Goes Wrong When Downspouts Are Undersized
A downspout that's too small usually tells on itself. None of these signs are about cleaning, they're about size.
The same corner spills every storm while the rest of the gutter is fine. You clean it, it's good for a bit, then the next big rain it's back.
On a steep roof, water sometimes comes down so fast it skips right over a small opening.
Water sits in the gutter between rains. All that weight hangs on the hangers, and eventually it pulls the gutter out of slope.
One spot in the yard keeps washing out, or a little ditch forms in the mulch. That's where too much water is landing at once.
For all of these the fix is the same: a bigger downspout, or another one.
Cleaning more often won't solve it. You'd just be clearing a gutter that was never going to keep up in the first place.
Installation Details That Determine Whether It Lasts
Where the downspout meets the gutter, the hole needs a clean cut and a good seal. A rough cut slows the water, and a bad seal lets it leak behind the gutter into the fascia.
Brackets should be close enough that the downspout doesn't wobble. A full one is heavy, and if it shakes in the wind it'll loosen its own fasteners over time.
Go easy on elbows. Every bend slows the water down and gives leaves a place to snag, so one that zig-zags around trim with four elbows will clog before a straight one.
Then the bottom. If the extension is just sitting there, the mower's going to knock it off, and once it's loose it's not doing a thing.
When to Upgrade Downspouts as Part of Other Work
Getting new gutters anyway? Do the downspouts at the same time.
A lot of the work overlaps, so it's an easy time to go to 3x4 if your roof needs it.
Same if you're going from 5-inch to 6-inch gutters. Hook a 6-inch gutter to a 2x3 downspout and you lose most of the benefit, because the downspout can't keep up.
Built an addition? That new roof might be draining into an old gutter, and the downspout on it was sized for the house before the addition.
Getting Downspout Work Done Right in Atlanta
A good assessment checks how much roof drains into each gutter, the pitch, what downspouts you have now, and how the ground slopes where each one lets out.
Ask why for every recommendation. You should hear which gutter has too much roof for its downspout, and how that lines up with the overflow you've been seeing.
At Gutters 4 Less we walk you through what we find with no pressure and no upsell. We'd rather add a downspout to a good system than sell you a replacement you don't need.
Gutters 4 Less handles
downspouts and drainage work across metro Atlanta, and a free estimate is the place to start.
You might also like
Gutters 4 Less Blog
