I have a 24'x24' cinder block foundation with dirt crawlspace straddling the border between 2 drainage basins. Water flows away from the house on all sides. The house has one support beam down the center directly below the front entry and stairs, and the load-bearing wall holding up the second floor is off-center by about 2 feet. The humidity and mold in the crawlspace are causing health problems, and concerns have been raised about the integrity of the structure in and below the first floor. I want to tear out the floors and fill the crawlspace in with cement to end all of these problems all at once, and serve as heat retention for the radiant floor heating that I plan to install. I just had a basement contractor come to the house, and he says it's a bad idea, but his reasoning doesn't add up to me. It just sounded like he was trying to talk circles around me to sell me vinyl encapsulation with a larger profit margin. What he said was that water would fill up into the cinder blocks and cause problems, but wouldn't specifically say what problems. It seems to me that vinyl encapsulation would be no different because it seals against the cinder blocks just the same as the vapor barrier in a slab. Also, it seems irrelevant considering the cement would be the new floor, so if the water table were to rise high enough for it come over the floor, we'd have problems anyway. Furthermore, with the house straddling two drainage basins, I wouldn't expect water to come up in the cinder blocks at all. He even mentioned that I'd need a sump pump the prevent water problems with a slab, but wouldn't talk to me about it when I asked. If it's not a terrible risk, I'm determined to have a slab poured. I grew up on a slab and loved the solid feeling under my feet, and we never had to worry about mold, termites, nor rot. Since nobody here will make a profit depending on what I choose, I'm hoping somebody can explain why a slab might be a bad idea without trying to sell me something else, or even better, tell me that the contractor is full of it and I have nothing to worry about.