With the fall and winter weather, the floor of the garage tends to be damp on a number of days, as if it were condensation. Do you have any suggestions as to how we can cure this problem?


Condensation, or moisture out of the air, causes the wet concrete garage floor. A combination of warm air with relatively high humidity coming into contact with the cold concrete garage floor is what causes the wetness. This is the same situation as cold glass on windows having water droplets inside your house during the cold winter months. Read more about window condensation.

Like the walls of a cave the water vapor condenses out of the warm air and turns into water droplets when it touches the cold stone, cave walls. Your concrete garage floor is like the cave wall, cold and moist. When the temperature drops and the humidity rises, the dew point is reached. The dew point is the point where the water loses its gaseous form turns back into water droplets.

There is no coating, paint or insulation that avoids this. Heating your concrete floor with a radiant heat system through the cold winter months will avoid this condensation problem on the few days that conditions are right. This is just the law of physics manifesting itself on your garage floor and is very common in the St. Louis area. Just keep an eye out so it doesn’t become a tripping hazard.

For help with any type of water or moisture issue, call the Mosby office at 314.909.1800 or contact us here. And for answers to other frequently asked homeowner questions, visit our Home Improvement Library.