Add A Downspout To Drain Water From Overflowing Roof Gutter

To add a downspout to control an overflowing gutter, whether putting up a whole new gutter or just supplementing what’s already there, is the same. In my case, the gutter spans the entire rear of the house. The long gutter section only has one downspout at the far end for all the water coming off a large roof area.

Another elbow may be required at the bottom of the downspout to direct the water away from the house. I drain the downspout water to my underground drain pipes through a receptor adapter for whichever size downspout you’re using.

You’ll need another adapter to connect the downspout to the gutter. Get a downspout outlet to match the size downspout you’ll be installing (2×3 or 3×4). Cut the hole in the gutter for the outlet, drop it in and apply a bead of seam sealer to cover the flange to seal the connection.

Decide where to put the second downspout. For me, the overflow problem was solved by connecting it to a downspout already in place; not adding an additional downspout. But depending on your problem, you have to think about this.

If the gutter was hung properly, it should be sloped slightly toward the existing downspout. For most gutters with a run with only one downspout, the optimal place will be to add a new downspout at the opposite end. So now the gutter has to be sloped toward both ends with the slope higher in the middle. Maybe the change is easy, maybe it’s not.

If adjusting the slope is too difficult, just add the new downspout somewhere near the center to drain half the gutter. To hide the new downspout, paint it the house color or along some vertical trim.

Remember to use seam sealer at the junctions.