I had a situation where water from my spa was seeping through the brickwork and then into the pool. I found a few microcracks in the grout on the top stone of my spa as well as a few other small cracks which I sealed with this silicone. During the Arizona summer, I left the silicone in the sun for 24 hours to give the silicone enough time to cure. I haven't had any leakage issues after using the silicone.