16.1. Section 16 does not apply to plans and specifications for architectural work (1) for the construction, enlargement, reconstruction, renovation or alteration of
(a) a detached single-family dwelling unit ; or
(b) a semi-detached or attached single-family dwelling unit, a multi-family dwelling that contains no more than four units, a mercantile occupancy, business occupancy, industrial occupancy or a combination of such dwellings or occupancies that is not more than two storeys and not more than 300 square metres in gross area after the work is completed and has a single basement level ; or
(2) for the alteration or renovation of the interior layout of any building or part of a building that will not change its occupancy or affect structural integrity, walls or firewalls, exits or access to exits or exterior cladding.