Why are my gutters overflowing?

Are the gutters overflowing because they are blocked with leaves? Keeping gutters clean of debris should be a part of every homeowner’s routine maintenance program. Depending on the surrounding trees, gutter cleaning may be required a few times a year or every month.

Products are available to prevent leaves from getting into the gutters. See gutter covers and gutter protectors. There are no standard tests to determine how well they perform, so the homeowner must rely on the word of the product manufacturer in regarding their effectiveness.

Are gutters overflowing because there are an inadequate number of downspouts (the pipe that goes down the side of the house and dispurse water to yard, garden etc.) on the house? There are construction industry standards to calculate how many downspouts are needed. You'd think contractors would follow them and calculate for each project, however, it's pretty rare. Many times the person is just using guidelines heard verbally from someone else and no one really knows what the standards are. When purchasing new gutters ask to see if someone is doing these calculations which should take into accou roof area, roof pitch and general weather patterns.

The adequacy of the downspouts can be checked during a heavy rainstorm. The first step is to clean out the gutters as described in Item 1. Next, if you don’t mind getting wet, and it is not lightning, go out and look at the gutters during a heavy rainstorm after it has been raining heavily for at least 15 minutes.

If you see any water overflowing the gutters, you have a problem. Any water overflowing out of the gutters is running down next to the house foundations. Even if the water is not getting into the basement, it could be causing unseen problems like eroding soil from under the house footings, which can lead to cracking of walls and ceilings.

How can I fix the problem? Assuming your gutters are in good condition and there are no other issues, the easiest solution to overflowing gutters are to either add another downspout on that run of gutter or to increase the size of the downspout. The best solution between these two is probably adding another downspout because the second downspout can act as a back-up downspout if the other one gets blocked.

Most downspouts are 2 in. x 3 in. in size. The next standard size is 3 in.x 4 in. While this doesn’t seem like much, increasing 2 in. x 3 in. downspouts to 3 in. x 4 in. doubles the capacity of the downspout. For Atlanta, we strongly recommend 3 in.x 4 in. If you choose to replace the existing downspout with a larger one, make sure the contractor increases the size of the corresponding hole in the gutter. It doesn’t do much good to install a larger downspout if the gutter hole is left small.

How far do the downspouts extend from the home? Three feet is accepted as the minimum distance needed to discharge the water coming off the roof far enough away from the house. While many homeowners do not like downspouts extending out this far, ten feet is probably better.

A lot depends on the soil around your house. Besides an extension, you will also want something that will prevent the rushing water from eroding your landscape. With homes, a common practice is to use something called a splash block. Discharge water beats on the block, not the ground. Splash blocks are OK most of the time, but might be lacking during torrential downpours. You may also want gravel or rocks be placed at in the discharge are to reduce the chance of erosion.

When designing the gutter system on a new house or for gutter replacement, a little pre-planning helps keep the horizontal run of the downspouts out of the way and less noticeable.

Be careful not to discharge downspouts too close to your neighbor’s property. Most towns and cities have ordinances that prevent downspouts from discharging too close to the property line and causing water problems for neighbors.

Do the downspouts drain into the footing tile system? It was common practice in the first half of the 20th century to have the downspouts draining into the footing tile system around the house. Vertical tiles were installed up from the footing tile system at each downspout location and the downspout was inserted into the open end of the tile. Sometimes the gaps around the downspout were mortared shut.

Having the water from the roof drain down next to the footings can add to the hydrostatic pressure problems, especially if the footing tile is leaking or blocked. This can occur over time due to soil movement or damage from tree roots. If the downspouts are draining into the footing tile system, the downspouts should be modified so they drain onto the ground and discharge at least 10 feet from the house. The vertical tile should be capped with a preformed cap or with concrete.

Footing tile systems sometimes drain into city storm sewer systems. Many cities and towns do not allow drainwater from the roof to drain into city sewer systems because the rainwater would overload the city sewer system. This could cause the sewer system to back up into homes and create enough water pressure to lift manhole covers off the ground.