Slab crack leaks are most common with balconies, penthouses, or any concrete ceiling structures. Once the water begins to make it past the waterproofing layer it will start to leak. This can happen for a multitude of reasons, such as natural deterioration, installation defects, faulty construction methods, etc. If you are struggling with concrete leaks CL Wizard is the solution for you! Our signature polyvinyl material will permanently fill your slab cracks.