The first floor of my split level home is a raised slab.  We are adding on to it. I’d like for the addition to have a conditioned crawl space.  Is there a way to do this?  I’m worried about the ‘gap’ between the different foundations as well as the potentional of having the subfloor of the crawl space against the concrete of the slab because of moisture.  Also, the fact that they would expand and contract at different rates.  Please give recommendations or anything else.  Thanks.