9.20.7.4 — Non-Conforming Chases or Recesses

(1) Masonry over openings shall be supported by steel, reinforced concrete lintels or masonry arches designed to support the imposed loads. (2) Except as provided in Sentences (3) and (6), steel angle lintels supporting masonry above openings shall conform to Table 9.20.5.2.A. (3) Steel angle lintels supporting masonry veneer above openings shall conform to Table 9.20.5.2.B. (4) Steel lintels described in Sentences (2) and (3) shall, (a) have even and level bearing and shall have not less than 150 mm length of bearing at end supports, and (b) bear on masonry, concrete or steel. (5) Steel angle lintels supporting masonry shall be primed or painted or otherwise protected from corrosion. (6) Steel beams supporting masonry veneer and wood stud walls above openings shall conform to Table 9.20.5.2.C. (7) Steel beams described in Sentence (6) shall be supported at each end by a steel column, and have a minimum 6 mm plate welded to the flange to support the masonry veneer.

(1) Except as provided in Sentence 9.20.7.2. (2) and Article 9.20.7.4., the depth of any chase or recess shall not exceed one-third the thickness of the wall, and the width of the chase or recess shall not exceed 500 mm.

(1) Except as provided in Sentence (2) and Article 9.20.7.4., no chase or recess shall be constructed in any wall 190 mm or less in thickness. (2) Recesses may be constructed in 190 mm walls provided they do not exceed 100 mm in depth, 750 mm in height and 500 mm in width.

(1) Chases and recesses shall be not less than, (a) four times the wall thickness apart, and (b) 600 mm away from any pilaster, cross wall, buttress or other vertical element providing required lateral support for the wall.