Section 398(1)(b) in The Punjab Municipal Act, 1999
(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 walls 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;