directly against a poured concrete basement wall. Since the climate here is mild, it would only be a 1/2" thick or so. The only quote I've gotten from a professional installer was extremely cost prohibitive.
You will not get the same results with the handy foam as you will with the pro spray however depending on the situation this might not matter. If you need the foam to act as a moisture barrier the 1 3/4 lb. handy foam may not qualify while a 2 lb. rigid foam will. Generally the cannister foams work ok for more confined shots but I would prefer the big gun for an open wall. It will also be kinda tough to maintain a 1/2 inch depth too. I think, (may be wrong) that the 80 lb. cannister sets are supposed to do about 400 sq. ft. one inch thick.