What Causes Moisture in the Basement in the Summer?

So the obvious sources of moisture in summer are rain and humidity. But, how does the moisture get in the basement?

Let’s start with humidity. Of course, in the summer, humidity is higher than in the winter. Why? Because warm air holds a lot more moisture than cold air. More dampness is noticeable because it’s more difficult for water to evaporate into saturated air than dryer air.

Ducts and old basement windows can let in moist air. When the moist air comes in and the basement is air-conditioned, this can cause condensation or dew drops that form on pipes, windows, or walls.

Also, when warm air rises in the basement due to the air leakage, moisture can be drawn up through sump pits or cracks and openings in the foundation.

Vapor diffusion and capillary suction can draw moisture in through the walls and floors that are made out of porous materials like concrete.

Rain is the main source of water in the basement especially when your basement is below the grade or ground. The ground is softer in the warm weather and can get over-saturated with water. The excess water has to go somewhere, so it leaks into cracks and openings in the walls and floor.

Whether the basement is finished, or unfinished damage can occur to either one. For example, the air gets musty and the odor is not pleasant. This does not contribute to the quality indoor use of the basement.

Carpets are stained, the drywall is degraded, and wood decays and rots. Cement walls and floors develop cracks and blistering and peeling paint. Even mold streaks can form.

This is not an insurmountable problem. Action can be taken to keep moisture out of your basement.