(1) The number size or position of openings in a wall, including chases or recesses regarded as openings in terms of subsection (20 or (30 of sections 17, shall not be such as to impair the stability of the wall or any part of it.

(2) The distance between any part of an opening made in an external wall and the outer face of return external wall, shall not be less than one-and-a-half times the thickness of the wall in which the opening is made, unless adequate support at the corner is provided by other means.

(3) Adequate means of supporting the super structure shall be provided over every opening in any wall.