For the purposes of—
Part I of this Act, and
any other enactment (whether or not contained in this Act) that relates to building regulations, or that mentions "buildings" or "a building" in a context from which it appears that those expressions are there intended to have the same meaning as in the said Part I,
and "construct" and "erect" shall be construed accordingly.
For the purposes of Part III of this Act, each of the following operations is deemed to be the erection of a building—
the re-erection of a building or part of a building when an outer wall of that building or, as the case may be, that part of a building has been pulled down, or burnt down, to within 10 feet of the surface of the ground adjoining the lowest storey of the building or of that part of the building,
the re-erection of a frame building or part of a frame building when that building or part of a building has been so far pulled down, or burnt down, as to leave only the framework of the lowest storey of the building or of that part of the building,
the roofing over of an open space between walls or buildings,
and "erect" shall be construed accordingly.