Don't Get Soaked by Wet Basements


In the 20 years I spent as a professional home inspector, the top three problems my home-buying clients were concerned about can best be summed up as this: water; water and water! But while leaks through roofs, pipes and basements are constant concerns, leaking basement always ranked highest as the home improvement problem most likely to send buyers running for the nearest open house.

Whether you are a buyer, seller or owner of a home, wet basements are always a concern. Not only is a wet basement unusable, flooded foundations can be seriously weakened and toxic mold, the newest threat to residential indoor air quality, can fester faster when an ample supply of water lies just below foot.

The good news about these unplanned indoor pools is this: while wet basements are often thought of as one life’s biggest home repair headaches, they are generally easy and inexpensive to fix. Yes – we said easy and inexpensive!

The Wrong Way to Fix a Leaking Basement

Ask 10 people how to fix a wet basement and you’re likely to get answers that include use of jackhammers to break up basement floors, backhoes to dig out dirt from foundation walls, sump pumps that have to be wired and plumbed, and other such drastic and expensive measures.

While these solutions may seem to make sense, they all attempt the impossible: to seal a foundation so tightly, that it will somehow hold off water like a boat. Well, unless your house is a house boat – it won’t float so you might as well stop thinking about all the ways to stop it from doing that.

Most people blame a wet basement on a high water table, the natural level of water in the soil under the building site. This is another myth that could not be further from the truth. Homes are not built below water tables. Builders attempting such a feat would find themselves constructing a foundation in a muddy mess. Likewise, basements that flood after a storm are also never caused by rising water tables. A water table moves slowly and seasonally. If your leaks show up after a heavy rainfall or snowmelt, the cause of your problem is far easier to spot and to fix.

Most basement leaks can be traced to trouble with the drainage conditions around the outside of the house. If too much water is allowed to collect in the soil around the foundation, it will naturally leak into the basement through the walls, or even up through the center of the floor.

The solution lies in improving these drainage conditions. Something that is easy, cheap and highly effective. Here’s where to begin:

Good Gutters

Roof drainage is, by far, the number one cause of basement leakage. Since roof surfaces are as large as the house, they collect lots of water in heavy rainstorms. What happens to that collected water can make the difference between a wet and a dry basement.

Properly designed gutters should have at least one downspout for every 600 - 800 square feet of roof surface. Gutters must be clean. Dirty gutters fill up and the water overflows directly where you don't want it to be: near the foundation. It’s also important to make sure the ends of the downspouts are extended to discharge at least 4 - 6 feet from the foundation. Spouts which discharge too close to the foundation are like big fire houses that just blast water into the basement.

If your yard and local building laws permit, one of the best ways to control roof drainage is to discharge downspouts into solid PVC pipes that run underground and discharge to the street or to another low-lying area. When making this improvement, be sure to pitch the pipe slightly towards the discharge point to avoid back-ups. And, don’t attempt this with the soft, flexible black pipe landscapers like to use around flower beds. This pipe is easily crushed and can not be “snaked” clean like PVC plumbing pipe can.

Sloping Soil

Next to gutter problems, the angle of the soil around the foundation perimeter can also cause wet basement woes. The soil should slope away from the house to keep rainfall from collecting against foundation walls.

The angle and type of soil are also important. The soil should slope downward 6 inches over the first 4 feet from the foundation wall. Thereafter, it can be graded more gradually but should never allow water to run back towards the house.

If grading needs improvement, use clean fill dirt (not top soil) to build up the soil around your house. Tamp the soil down to the correct slope and finish with a layer of top soil and grass seed to prevent erosion. Or, just use stone or mulch. Whatever the top layer is, be certain the slope is established with the fill dirt - or else the water will just run through the more porous material and into the basement. Also, don’t use straight top soil for the grading improvement. This kind of soil is too organic and will hold water against the foundation, which is the opposite of what needs to be done. ,

It is also important to avoid landscape treatments that hold soil to the house. A brick, stone or landscape timber edging around flower beds adjacent to foundation walls may look attractive, but these edges can prevent water from draining away from the foundation and increase your risk of flooding.

Following these simple guidelines will solve 99% of wet basement blues. The improvements are inexpensive and can usually be done yourself or with a little help from your friends.

Note: Tom Kraeutler is the Home Improvement Editor for AOL and host of The Money Pit, a nationally syndicated home improvement radio program. To find a local radio station, download the show’s podcast or sign-up for Tom’s free weekly e-newsletter, visit the program’s website at www.moneypit.com.

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