Does your basement feel damp? Do you feel a musty smell every time you go to the basement, more so after a heavy rain? Water may be leaking into your basement or you may only have a humidity problem.

Here is how to make sure the culprit is a water leak and how to prevent water from further leaking into your basement.

A thorough visual inspection of the basement walls and basement floor will usual reveal whether water is leaking into your basement, especially after a heavy rain.

If the exterior drain gets clogged and hydrostatic pressure builds up against your basement wall, water may leak through the joint between the floor and the wall.

In addition, if you basement wall is made of clay tiles the mortar joints can get loose and water leaks through. For stone wall, water may leak through the joints between the stones. Block walls may also leak at the mortar joints and sometimes the block itself can crack and allow water to leak through. Likewise, concrete basement walls may crack.

Carefully inspect all the basement walls, the joint between the floor and the wall and the basement floor for any sign of water leakage.

In finished basements you have to look for moisture signs on the drywall and floor. Presence of mold, paint pealing and drywall or floor swelling a sure signs of water leaking through into your basement. Affected drywall and flooring must be removed to further investigate and repair the cracks.

Here are the most easy ways to repair the cracks and waterproof your foundation or basement floor:

  • patch the cracks with hydraulic cement compounds and apply waterproof paint or hydraulic cement on the inside wall
  • injected the cracks with specially formulated epoxies or polyurethane grouts and apply waterproof paint or hydraulic cement on the inside wall

I do not generally recommend installing an interior water drain, also known as French drain, as it usually gets clogged over time. Instead, you can install a subfloor drainage system equipped with a sump pump system.

In extreme cases, exterior excavation will be required to waterproof the foundation from the outside. Some companies may inject special crack filling grouts around the outside of your foundation and will apply waterproof paint or hydraulic cement on the inside wall.

If you do not see any evidence of water leaking into your basement, the musty smell is most likely caused by the high humidity in your basement. In some homes, the hydrostatic pressure on the walls pushes water vapor into the basement and increases the humidity level.

An inexpensive and easy-to-use hygrometer, or humidity sensor, can confirm whether your basement has too much humidity. Humidity levels over 60% typically indicate that your basement has a humidity problem.

Installing and running a dehumidifier will definitely help maintain the humidity levels under control and the musty smell will eventually disappear from your basement.