Silicate sealants are an excellent choice for protecting concrete surfaces. They can take up to 90 days to fully react beneath the surface, but the initial chemical reaction occurs within the first 72 hours. If you apply the sealant and it rains within 24 hours, the rain can dilute unreacted material beneath the surface. Generally, these sealants take about 48 hours to completely dry, so it is important to wait before doing any activity on the surface.
However, if absolutely necessary, you can walk on them at 12 o'clock. To guarantee that the sealant is completely dry before applying it, open as many windows and doors as possible, use a fan to move air across the floor, and do another test after 24 to 36 hours of drying. If the building's heating, ventilation, and air conditioning system is working, run the air conditioner to help remove moisture. When the humidity readings drop low enough to seal the concrete (4 pounds or less), apply the sealant in the afternoon or evening, when the humidity is lowest. It's a good idea to wait at least two days without rain for the pavers to be completely dry before applying the sealant.
Another option for sealing concrete surfaces is using a basic plunger sprayer, similar to the one that would be used to apply gardening chemicals. Not only are they nearly twice as thick as an acrylic sealant (3 to 5 thousandths of an inch), they also produce a very durable, chemical-resistant coating that doesn't yellow. Unlike acrylic sealants, they don't change the look of pavers and work completely below the surface.
