How to find and cure the basement leak


IF YOU HAVE even the slightest problem with water coming into your basement and you live on the East Coast, Hurricane Floyd surely put your walls to the test. Several readers have written Ron with questions about how to detect and prevent leaks in their basements. (And others, too busy emptying buckets, haven't had time to compose a message.)

Finding the source of such a leak can be very difficult. Where the water is getting in on the outside may be far removed from where it is showing up on the inside. The best way Ron has found to locate a leak is with an ordinary garden hose. Wait until you have a nice dry day to do it.

Start at one end of the wall where the water comes in. Slowly work your way along the wall, letting the water from the hose run against the wall. You will need someone inside to tell you when the water begins to come in. "Slowly" means very slowly, about 1 foot every 5 minutes. The water may be entering a crack, filling up to a point inside the wall, and then leaking on the inside. The water-hose method also works very well for finding the source of roof leaks.

Once you find the source of the leak in the wall or roof, you know where to correct the problem. However, the hose system may or may not work as accurately on an underground, or basement, wall.

Actually, there are several things you can do to help prevent foundation leaks.

First look at the grade of the land around the foundation. It should always fall away from the house. Check the way the downspouts are located and where the water from them is directed. If a downspout is dumping water along the wall, it is likely to be at least contributing to the problem. Be sure you have splash blocks under the downspouts and that the water is being directed away from the house.

If you have rain leaders (underground pipes) that your downspouts feed into, check to see that they are not clogged or broken. Old terra-cotta rain leaders often break and fill with dirt. If they don't drain, you should either replace or abandon them. Planters or landscaping timbers around the foundation walls can trap water and cause it to run back to the wall.

Those are the first things you should check, and correcting them could solve your problem simply. However, if you still have leaks, you most likely need professional help.

There are many ways to deal with leaky basement walls. The best way is to dig around the foundation, all the way down to the footing, and re-waterproof the walls. This is very expensive and makes a really big mess in your yard.

The alternatives deal with the problem on the inside of the walls. The most common solution is to install or repair an existing french drain. The drain is installed by removing about one foot of the concrete floor around the perimeter of the basement. Then you dig down to the footing, below the slab, and install a perforated pipe that drains into a sump pump pit.

The block walls need to have holes drilled into them to allow any water to drain into the french drain. Then the concrete is replaced, usually with a gap at the wall to allow any water that might run down the wall to go into the drain.

There are some newer systems that are made of vinyl or PVC (polyvinyl chloride), in which sheets of material are applied to the walls to direct the water to a base channel 3 or 4 inches high that is applied to the floor with an epoxy glue. The base channel carries the water to the sump pump. These systems do not require breaking up the floor. They also do not stop the water from coming through the wall, although they control it once it does.

For very minor leaks, you can get an expanding cement, called hydraulic cement, to patch a small hole. Some types will stop the water while it is leaking. There are also waterproofing masonry paints that work well for sealing walls and help to keep the humidity level in the basement under control.

If you feel you need to hire a waterproofing contractor, there are a lot of good ones out there. Be sure to check references and get prices from more than one. You will likely get a variety of solutions from different contractors: You'll just have to decide which is the best one for your situation.

Ron Nodine is owner of American Renovator Inc., a Baltimore design-build remodeling firm, and former president of the Remodelors Council of the Home Builders Association of Maryland. Karol Menzie is a feature writer for The Sun.

If you have questions, tips or experiences to share about working on houses, e-mail Ron at or Karol at Or write c/o HOME WORK, The Sun, 501 N. Calvert St., Baltimore MD 21278.

Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.

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