The provisions of this Act and of any rule or bye-law made thereunder relating to construction and reconstruction of buildings shall also be applicable to any alteration thereof or addition thereto:
Provided that repair works using materials of the same nature and value to keep the building as such without enhancing its value and without changing its occupancy and use and which do not affect the position or dimension of a building or any room therein shall not be deemed to be an alteration or an addition for the purpose of this section changing of roof or construction of walls by using a different material and other similar works which enhance the value of the building to any extent will not be treated as repair but as a new construction.