An Interior pressure relief system or French drain is a way to relieve hydrostatic pressure from under the concrete slab as well as draining the cinder blocks. The floor is broken away from the wall between 12-20 inches. A trench is then dug out to install filter fabric, 4" pipe and gravel. The cinder blocks are weeped to allow water to flow out and into the newly installed pressure relief system. The water is then led to a sump pit/pump or a gravity drain away from the house.