(1)In this Chapter, unless the context otherwise requires, the expression "to erect a building" means -(a)to erect a new building on any site, whether previously built upon or not;(b)to re-erect-(i)any building of which more than one-half of the cubical contents above the level of plinth have been pulled down, burnt or destroyed, or(ii)any building of which more than one-half of the superficial area of the external wall above the level of plinth has been pulled down, or(iii)any frame-building of which more than half of the number of posts or beams in the external walls have been pulled down;(c)to convert into a dwelling house any building or any part of a building not originally constructed for human habitation, subsequently appropriated for any other purpose;(d)to convert into more than one dwelling house a building originally constructed as one dwelling house only;(e)to convert into a place of religious worship or a sacred building any place or building not originally constructed for such purpose;(f)to roof or cover an open space between walls or buildings to the extent of the structure formed by the roofing or covering of such space;(g)to convert two or more tenements in a building into a greater or lesser number of such tenements;(h)to convert into a stall, shop, office, warehouse or godown, workshop, factory or garage any building not originally constructed for use as such, or to convert any building constructed for such purpose by sub¬division or addition, in greater or lesser number of such stalls, shops, offices, warehouses or godowns, workshops, factories or garages;(i)to convert a building, which, when originally constructed, was legally exempt from the operation of any building regulation contained in this Act or under any rules or regulations made under this Act or contained in any other law for the time being in force, into a building which, had it been originally erected in its converted form, would have been subject to such building regulations;(j)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;(k)to make any addition to a building;(l)to close permanently any door or window in any external wall;(m)to remove or reconstruct the principal staircase or to after its position.(2)For the purpose of this Act, "use group" or "occupancy" shall mean the purpose for which a building or part of a building is used or intended to be used. For the purpose of classification of a building according to occupancy, occupancy shall be deemed to include subsidiary occupancies which are contingent upon it. The classification of occupancy shall include residential, educational, institutional, assembly, business, mercantile (retail), mercantile {wholesale), industrial, storage and hazardous. The principal occupancy shall be the occupancy covering more than 50 per cent of the floor area of a building. In case no single occupancy covers more than 50 per cent of the floor area of a building, the building shall be classified as "mixed use building". The classification of buildings based on principal occupancy, shall be as follows :"residential building", "educational building", "institutional building", "assembly building", "business building", "mercantile building (retail)", "mercantile building (wholesale)", "industrial building", "storage building", and "hazardous building".
