How to Seal Leaking Block Walls in Your Basement So How to Seal Leaking Block Walls in Your Basement. Basement waterproofing has been around since basements have been constructed below ground level and sometimes even below the water table. The basement waterproofing design features are critical as basements are often subject to groundwater (hydrostatic) pressure. … Continue reading How to Seal Leaking Block Walls in Your Basement