U) to convert into or use as a dwelling house any building which has been discontinued as or appropriated for any purpose other than a dwelling house.

Prohibition of erection of building without sanction : No person shall erect or

commence to erect any building or execute any of the works specified in section 244 except with the previous sanction of the Commissioner, nor otherwise than in accordance with the provisions of this Chapter and of the bye-laws made under this Act in relation to the erection of buildings or execution of works.