brett I live in New England also, central NH. I also own a water control business. What we use for this is a product called ThermalDry. It is a dimpled, polyethlene that rolls out on the concrete and you put 5/8" underlayment over it and fasten to floor. What this does is keeps any moisture that comes thru your slab from reaching the flooring. The moisture thaen is vented out fro under the flooring so there is not mold or mildew build up. ThermalDry will also riase the temp of the floor around 10 degrees. This systems costs around $3 sq' to install and does all of this while only taking 7/8" of head room away.