Foundations are rarely permanently waterproof. Even foundations that are built with all the best wet-basement defenses are likely to leak eventually. The house shifts and settles over the years, causing gaps and cracks to form. Slow changes in the arrangement of landscaping, walks, drives, and gutters contribute to excessive water in the soil around your foundation. Sooner or later, the water finds a way in. The problem is very common among homes over 25 years old and often shows up in much newer homes as well.

Because solutions are rarely simple and because the waterproofing industry has a deservedly rotten reputation, many homeowners put off dealing with the wet basement problems. The problem only gets worse with more wetness more often. In no time, people end up with a basement full of rusted, rotted, and moldy heirlooms. Termite infestation is another common outcome of a neglected wet basement.

If your walls are occasionally damp, especially during humid months when the windows are open, your problem could be condensation rather than seepage. To find out if this is so, securely tape a 10" x 10" piece of plastic wrap onto the basement wall in an area where you have noticed dampness, sealing the edges of the plastic wrap with the tape. Check on the plastic over the next few days. Eventually you will see moisture: if the moisture is on the wall side of the plastic, you've got a leak; if the moisture is on the room side of the plastic, you've got a condensation problem.

Condensation problems are solved by reducing the moisture in the air or improving the air circulation. It may be a simple matter of not opening lower-level windows during muggy summer evenings. For a complete description of condensation remedies, ask for the guide mentioned at the end of this article.

Another common and easy-to-fix cause of water problems is flooded window wells or stairwells. Flooded window wells can usually be prevented by adjusting gutters or installing plastic well covers. It is very difficult to keep an exposed stairwell drain clear of debris. Most people decide the best solution is to have a roof built over the stairwell.

If your wet basement problem is a result of seepage, there are basically two approaches you should start with. First, have a good look at how the water flows around your home during a heavy rain.

Regrade the ground, reconfigure gutters and replace patios and walks if they have the effect of directing water near the foundation of your house. Surface water near the foundation will saturate the soil and find its way through tiny cracks and fissures into your basement. Next, inspect any exposed walls inside your basement. Caulk any gaps or cracks. With luck, these steps will stop the problem, but many people have to go the next step and have a sump pump and drain system installed.

In a sump pump and drain system, pipes with holes in them are installed beneath the basement floor. Water in the soil trickles into the pipes which in turn drain into a concrete pit. The pit contains a pump that turns on whenever water starts to fill the pit. The pump expels the water harmlessly out a pipe. The water level in the soil never reaches the level of the basement floor and the basement remains dry.

Here are some answers to common questions about waterproofing:

Q. I remember seeing a TV report about sump pumps and drain systems that indicated the whole thing is a rip-off. Now you say it's okay. What's the deal?

A. Sump pumps deal with a symptom, namely excess water in the soil, rather than the cause, poor drainage. This is true. That is why you should attempt to solve the problem by looking at water flows first. However, if those efforts are unsuccessful, the sump pump is an effective remedy.

Q. I heard of one neighbor who paid $14,000 for a sump pump system. Why do they cost so much?

A. They shouldn't. Unfortunately, price gouging by unscrupulous companies is hardly a rarity in the waterproofing industry. For most homeowners, the system should cost in the $2000-$5000 range.

Q. I can't afford to spend much money on my damp basement problem. What can I do that's inexpensive?

A: Simple things like keeping your gutters clean and extending the downspouts so that water is directed well away from the foundation can reduce or eliminate the problem. Inside, keep things in the basement at least one foot off the floor and at least one foot away from the walls to allow good air circulation and minimize the damage caused by moisture.

Q. I'm no expert and don't really understand what needs to be done outside to deal with drainage problems. What can I do?

A. Hire a home inspector who specializes in water problems. For under $200, the inspector will come out, do a complete analysis and make specific recommendations.

Q. I'm getting ready to sell my house. On very rare occasions we've had moisture in the basement. We've repainted and there is no evidence of moisture. Do we have to disclose anything?

A. I'm not a lawyer, but in general you have to tell the truth. Some potential buyers may accept your explanation and remain interested in the house. Others will reject the explanation, fearing the problem may be more serious. In general, buyers don't want to buy your problems. For most sellers, installing a sump pump and drain system will give buyers the assurance they want. Such systems are the only treatment that comes with a guarantee.

Q. A contractor told me about a treatment where they squirt something into the soil around the foundation that blocks out the water. Does it work?

A. Most experts agree that this approach is a waste of money. Stay away from it and anyone who recommends it.

Q. When we first bought the house years ago, the grading was perfect. Now, the yard and the patio tilt slightly towards the house. What caused the shift?

A. The shift is caused by settling of the soil around the foundation. It occurs at every home. When soil is dug up, it expands to as much as three times its original volume. This is why when you turn over the soil in your garden; the bed becomes so much fuller. The same thing happens when they dig a hole for your foundation.

When they refill the hole around the foundation, the builder tries to tamp it down, but inevitably it remains a bit puffed up. Over the years it settles back to its original density. Walks, patios, and driveways settle with it. Dirt can be added to depressed areas of earth, but paved areas usually have to be replaced.

by David Hollies, reprinted courtesy of HomeAdvisor.com