Section 12. Setting back of buildings to building line or control line.

Whenever any building or any part thereof erected before the appointed day referred to in section 9 lies between the building line and the middle of the highway, the Highway Authority may, whenever any such building or part has either entirely or in greater part been taken down, burnt down or fallen down, by notice require such building or part when re-erected to be set back to the building line or control line.