No principal structure to be located, placed or erected on any residential parcel shall have a width or depth less than 22 feet, except that in the R-40A, R-40B, R-40E, R-40W, R-B-1, R-B-2, R-B-3, R-B-4, R-B-5, R-B-6, and R-B-7 Zoning Districts, there shall be no minimum width or depth requirements for a principal structure. Metal clad buildings and pole barns shall not be permitted in a residential zone except for commercial farms in the Rural Residential Zone and the total ground level floor area of an attached accessory garage for a single-family or two-family dwelling shall not exceed the total ground floor living area of the dwelling.