Why is the slab damp? Carpet, is rarely a good solution over concrete.
There are insulated subfloor panels that can be used as well to have a finished floor installed over top.
Scott,
The easiest thing to do is check in the attic and look at the sheathing. If there is any mold growth, you can tread it with a proper mildewicide and make sure that the fan ducting is extended ... read more