Rust Bullet Concrete coatings are moisture sensitive. Even the smallest amount of moisture on the surface can cause a coating failure. A moisture meter, calcium chloride test, or a plastic sheet test can be conducted to check for moisture.

To perform the plastic sheet test for moisture, cut a sheet of plastic into roughly a 1″x1″square (one side cut from a gallon resealable bag works great) and tape the edges onto the floor. Make sure to completely seal the edges so no air can escape. Leave it for 24 hours. Look for condensation on the underside of the plastic sheet or a visible darkening of the slab below the plastic that is damp to the touch. Both are signs of an excessively moist floor.

Another way is to use a moisture meter or calcium chloride test kit which are sold at home improvement stores. Follow the provided directions if using either of these methods.