Here's Why Your Garage Floor Is Always Wet (& If You Should Worry)

Have you noticed that your garage floor is often wet? It may seem like a strange phenomenon, but a damp garage floor is something that plagues many homeowners. It's happened enough that it has been given its own name, sweating slab syndrome. Typically, sweating slab syndrome occurs because of the difference in temperatures from the ground and the slightly warmer air. 

Specifically, this happens when warmer air comes into contact with your concrete garage floor that is a cooler temperature. Condensation on the floor will appear if the air cools at or below the dew point. While this is the most common explanation for your damp garage floor, it isn't the only one. It is also possible that moisture is coming up from the ground below your floor and seeping through the concrete to gather on its surface. This could have happened if your garage floor wasn't built with some form of moisture barrier. 

Regardless of the reason behind your damp garage floor, it is something you should concern yourself with. Slick moisture can easily become a safety hazard, risking bad falls or other injuries. The continued moisture can also end up causing damage to your floor or stored items in the garage as well as becoming a breeding ground for mold.  How you stop the floor from feeling damp will depend on whether the condensation is coming from the air or coming up from below ground. 

To figure out what is causing your damp garage floor, you can perform an easy test. Simply grab a bit of plastic sheeting, clear and dry a section of the floor, and tape the plastic sheeting down. The following day, check the sheeting for moisture. If there is moisture above the sheeting, the condensation is coming from the air and there are some options to prevent it. If, however, the moisture is below the sheet ... then your condensation is coming up from the ground and you have a bigger problem on your hands. In that case, it's best to call a professional out to assess your situation.

For condensation that's forming from warmer air, you have a couple of different possible solutions. A fan or dehumidifier can help regulate the temperature so that it doesn't reach that dew point. If you want to add something on top of your concrete as a more permanent fix to the sweating, know that there is more to it than simply slapping it on. 

There are advantages and disadvantages to adding epoxy flooring and depending on whether or not your floor has a vapor barrier, they may make your problem worse by trapping moisture from underground. If you know your moisture problem is from the air, a good concrete floor sealer like Siloxa Tek 8500 will work safely and keep you from worrying about that sweaty floor again for quite some time.