Waterproofing Cracked Basement Floors In Northern Virginia is Fairfax Contractor’s specialty. But the big question is how to stop water from entering your concrete basement slab. There are three main reasons your concrete basement slab is leaking. Fairfax Contractor can solve all types of waterproofing caused by a cracked basement floor. One reason your basement slab is flooding your basement is you have a major crack in the concrete that is allowing water to pass through this crack. The second reason waterproofing problems are present in your basement slab is the condition of the concrete. The third problem is your Northern Virginia home is located in a flood zone, and the hydrostatic water is leaching into your basement slab.