(1)When any building or part thereof aboutting on a public road is within a road alignment defined under Section 238 the Executive Officer may, whenever it is proposed-(a)to rebuild such building or take it down to an extent exceeding one-half thereof above the ground level such half to be measured in cubic feet; or(b)to remove, reconstruct or make any addition to any portion of such building which is within the road alignment;in any order which the issues concerning rebuilding, alteration or repair of such building require such building to be set back to the road alignment.