It even stops active water seepage under hydrostatic pressure. It permanently waterproofs and damp-proofs poured concrete, cinder blocks, and mortar . If your basement or slab is new or appears dry, now is the time to seal the concrete with RadonSeal to prevent future moisture or radon problems, and to preserve it against efflorescence and deterioration. The exterior asphalt coating on the foundation cracks under attack by chemicals from inside the concrete. Concrete becomes more permeable to moisture and radon as it ages.
Houses settle and underground water flows change.
A new building on the street or blockages in the drain system, gutter or leader may change your water situation. RadonSeal only seals concrete, it is not a miracle cure. You still must caulk all cracks and openings. After sealing the inside of concrete with RadonSeal, its exterior surface is still vulnerable to water leaching, particularly cinder blocks. You should still take the basic steps to eliminate water around your foundations like downspout extensions and soil grading.