9.15.4.7 — Reduction in Thickness

(1) Where two or more wythes are tied together with metal ties of the individual rod type, the ties shall conform to the requirements in Sentences (3) to (6). (2) Other ties may be used where it can be shown that such ties provide walls that are at least as strong and as durable as those made with the individual rod type. (3) Metal ties of the individual rod type shall, (a) be corrosion-resistant, (b) have a minimum cross-sectional area of not less than 17.8 mm², and (c) have not less than a 50 mm portion bent at right angles at each end. (4) Metal ties of the individual rod type shall, (a) extend from within 25 mm of the outer face of the wall to within 25 mm of the inner face of the wall, (b) be completely embedded in mortar except for the portion exposed in cavity walls, and (c) be staggered from course to course. (5) Where two or more wythes in walls other than cavity walls and masonry veneer/masonry back-up walls are tied together with metal ties of the individual rod type, the space between wythes shall be completely filled with mortar. (6) Ties described in Sentence (5) shall be, (a) located within 300 mm of openings and spaced not more than 900 mm apart around openings, and (b) spaced not more than 900 mm apart horizontally and 460 mm apart vertically at other locations. (7) Except as required in Sentences (8) and (9), where the inner and outer wythes of cavity walls are tied with individual wire ties, the ties shall be spaced not more than 900 mm apart horizontally and 400 mm apart vertically. (8) Within 100 mm of the bottom of each floor or roof assembly where the cavity extends below the assemblies, the ties described in Sentence (7) shall be spaced not more than 600 mm apart horizontally. (9) Within 300 mm of any openings, the ties described in Sentence (7) shall be spaced not more than 900 mm apart.