There are two reasons why concrete sweats. The first and most common reason why concrete sweats is that the concrete is cold and the air is warm. When the concrete is cold and the air is warm, the moisture in the air hits the cold concrete and condensation forms on the surface. Have you ever taken an ice cold soda and left it on the counter? The entire outside of the soda can will be dripping wet with water because the soda is cold and the air is warm. The same exact thing happens with concrete. Sealers can't stop condensation. Sealers can reduce the absorption of water on the surface, but they can't stop condensation from forming. In order to stop concrete sweating caused by condensation, you need to either warm up the concrete or cool down the air temperature.

The second cause of concrete sweating is sub surface moisture. To be honest, this is very rare, especially in a garage or Garage Floor Coatings to Stop Sweatingwarehouse. Subsurface moisture is caused when hydrostatic pressure pushes water and moisture up through the concrete from below the surface. It is very common for concrete slabs to have issues with moisture, but concrete sweating is rarely caused by subsurface moisture pushing through. 

It is very hard to test the cause because most moisture vapor tests and even plastic tests, will measure moisture in the air as well as below the surface. The results of the tests won't be accurate. There are a few things you can do to try and reduce concrete sweating, and protect concrete against the damage and deterioration caused by the absorption of the condensation.

1. You can run a de-humidifier to try and reduce the moisture in the air. As mentioned above, condensation forms when moisture from the warm air lands on the cold concrete. Condensation is primarily caused from a difference in temperature however so you may not notice much of a difference, if any at all, by running a dehumidifier. 

2. When the water droplets hit the concrete, the concrete gets wet. In most cases, condensation is just an annoyance and there isn't enough water on the surface present to cause staining and deterioration of the concrete. You can apply a water repellent sealer, like the Armor SX5000, or a garage floor coating, like the Armor AR500 or Armor UTN60, to protect the concrete against staining and deterioration caused by water absorption.