Having 2 story addition built. My concern is the framing on the concrete slab is uneven. 20' long wall; one corner framing is recessed 3", on other corner framing is outside slab 1/2". Inside framing is square. How is vinyl siding supposed to be installed? Asked contractor, do not get a straight answer. Think I am being hosed. Does anyone have any knoweledge on this subject? Thanks.