How can I improve my outdoor area to avoid getting water in my basement and near-flooding in my backyard?


How can I improve my outdoor area to avoid getting water in my basement and near-flooding in my backyard?

Asked by Susan Free

The wall that is leaking has a foot-wide flowerbed against it and then a sidewalk. I would like to get rid of the flowerbed and seal it in some way but am unsure what could be used to provide a watertight seal against the exterior wall. In the rear of the yard, an enormous amount of water accumulates in one of the back sections, where there is a small retaining wall. I'm not sure if it would help to get rid of the wall altogether. The problem started there after having a pool set up year after year, which I won't be putting up again because of this problem.

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Ryan Flegal's picture

Waterproofing basements can be tricky. The right way to properly waterproof walls and floors requires careful planning during construction. But many of us are left doing the best we can with old houses or homes with basement moisture problems.

We recently moved into a house with a basement that floods. There are a number of things that we are doing to minimize the chances of water intrusion.

Here are a few low-cost improvements you can make to minimize water intrusion in any basement:

  • Install gutters around your roof.Then make sure the downspouts turn and move water away from the base of your house. Roofs shed a tremendous amount of water and concentrate that water right next to your house and into the soil adjacent to your basement walls. Directing that water away is key.
  • Better yet... capture the water from your downspouts in rain barrels or cisterns for later use irrigating your landscaping. I use 275-gallon used IBC food-grade totes for this purpose (you can buy them used on eBay for about $100).
  • Make sure overflow water is directed away from the house. Gently slope the soil adjacent to your house to shed water away from your home. You don't need a lot of slope. A quarter-inch drop for every foot out from your house should suffice. But you want to avoid having any ponding water next to your home. Even small puddles allow time for water to thoroughly saturate the soil next to your basement walls.
  • Consider adding a French drain or swale. Many homes are built on sloping lots (even just a slight slope counts). So the water from the uphill side of the lot runs down toward the house. Consider adding a swale or incorporating landscaping to capture the water away from the house or move it to the sides of the lot where runoff can pass the house without running up against it.
  • Perhaps you might install a water infiltration pit. This is exactly what it sounds like; a shallow and wide pit to capture rainwater and replenish groundwater. If you have a grass lawn, the pit can also be grass, just contoured to collect and absorb rainwater. This keeps rainwater onsite, which is much better than sending it to oceans and rivers, picking up street contaminants along the way. An infiltration pit would need to be properly planned and sized based on your soil type and the area of watershed it needs to accommodate. The pit would of course need to be located away from the house.
  • I'm not a big fan of adding more concrete to solve flooding problems. Some concrete, to create a curb or channel to move water to one side or another, can be very effective. But it is very hard to keep water out of the ground altogether. And our ground needs water to replenish underground aquifers that help sustain balance in our ecosystems.

It is hard to know the right solution for your house without visiting the property, but I encourage you to look at the relatively inexpensive improvements I listed above before you consider pouring concrete or undertake a really expensive project like digging out the side of your basement walls to waterproof the walls themselves.

Remember that it is important to solve the issue of where the water is coming from. If you instead focus on just waterproofing one area (like the basement walls), you may end up with waterproof basement walls only to see the water seep in through the basement floor.

You may want to contact a local green landscaping expert or rainwater catchment expert to help you evaluate your specific site. Here's a link with a list of green landscapers. Once you take proactive steps to move the water away from your house, I think you are likely to have a dry basement.

For more information:

Read Shannon Demma's "Should we install cork flooring in our moisture-prone basement?" and David Edwards' "What type of board insulation is best to avoid basement moisture issues?" to learn more about resolving basement moisture infiltration.