I plan on having a slab foundation installed for single-story addition. It is on grade and my walls will be light framing (no brick). I live in the northern Virginia area and wondered if I need a stem wall slab or is a monolithic slab sufficient? I've read up on the codes and it seems that monolithic with insulation protection on the vertical portion of the base is what is required along with a gravel base, rebar, and vapor barrier. Does anyone have any experience in this climate with foundations of this type? I'm not doing it myself but I thought I'd try to get more insight before I start calling contractors.