We just moved to a new house (built in 1979). The previous owner had the walls and floor painted/sealed, we repainted/sealed the walls and put down a vinyl no glue floor (we did not re-paint/seal the floor). We just pulled back the vinyl floor and found mold and some of the paint was coming up. I'm sure we will have to pull up the flooring and re-paint/seal the floor and add a dehumidifier, but my question is: We have about a one inch gap between the basement walls and the concert floor. Could this gap be filled in? What is purpose for this gap? Any other suggestions for keeping a basement dry? We do have a sub-pump one corner.