AVOIDING WET BASEMENTS – Part 1 – Downspouts


One of the most common problems I come across is missing and loose or otherwise improperly installed down spouts. In the Midwest we have fairly flat properties and the soil is generally a layer of top soil over a clay base. Many of the homes I inspect have several issues related to water control and drainage. This week and most weeks in the spring and summer I hear about wet basements. Most basement leaks stem from misdirected downspouts. Sometimes homeowners try to fix a wet basement with a sump pump but if the moisture is seeping through a wall and creeps out onto the floor, a sump pump will not help. I always emphasize the importance of controlling rain and melt water on the outside first.

There are two major repairs you can do to keep your basement dry. 1. Move the water from the roof a long ways from the home. Many inspectors recommend at least 8’ but I’ll go a bit further to say make sure the discharge of the downspout is landing in an area where the water will continue to move away on its own. All too often I see 8-10ft extensions added but the water is pooling and back grading towards the home none-the-less. I often recommend using a fence as a fastening device to add more length to your roof control systems. In this way you can move water along the fence and discharge it at the front or back of the yard where it can run to the street or the back alley. In a heavy rain this could make the difference between a wet or dry basement. 2. Secondly always try to use a clay base to create a positive slope away from the home. If you have a concrete basement this should not be a difficult task, simply remove the top soil and slope away from the wall with clay. Depending upon the severity of the problem you may want to add a plastic water drainage plane and rock as ballast. If the slope is not too negative simply correct the slope and add a layer of top soil on top and seed again.

Correcting the slope and filling in low spots commonly found under decks, together with properly positioned downspouts will usually keep your basement dry. If you have a deep basement you will likely need to install window wells in order to bring up the slope near the basement. Remember that some basement windows need to be a means of egress so a large window well will be required. In extreme situations the property slope may not be repairable. In these situations you may need to add an exterior sump which is a topic for another blog. Good luck and call for free advice anytime.

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