No accessory building located in any zone shall be either a quonset or a trailer, except for temporary structures erected or placed in the B-2, M-1 or M-2 Zones for a period not exceeding two months, or as extended pursuant to subsections 13-10.6d, 10, 13-10.8d,3 and 13-10.9d,1, or emergency or temporary structures in the R-8 Residential Zone for an initial period not exceeding six months, or as extended up to three months, as provided in subsection 13-10.4d,9 of this chapter, Temporary Uses and Structures, while a principal building is being repaired or modified.