Roof Sheating Edge Support
(1) Except as permitted in Sentence (2), where panel-type roof sheathing requires edge support, the support shall consist of,
(a) metal H clips, or
(b) not less than 38 mm by 38 mm blocking securely nailed between framing members.
(2) The supports referred to in Sentence (1) are not required when tongued-and-grooved edged panel-type sheathing board is used
Article 9.23.15.6. Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only.
To prevent damage to the roof covering when thinner panels are used, support the joints with 38 × 38 mm (2 × 2 in. nominal) blocking nailed securely between the roof framing members, or by metal H-clips inserted between sheets. H-clips are widely used because installation is simple and economical.
It is good practice to stagger the location of fasteners at the edges of adjoining panels. Staple fasteners for 9.5 mm (3⁄8 in.) roof sheathing must be at least 1.6 mm thick, 38.1 mm long with a 9.5 mm crown (1⁄16 in. thick, 11⁄2 in. long with a 3⁄8 in. crown), and be driven with the crown parallel to the framing (Table 38 on p. 307). Thicker roof sheathing (Table 22 on p. 287)—no less than 15.5 mm (5⁄8 in.)—is required for built-up roofing on a low-slope roof to be used as a walking deck.
Source : Canada Mortgage and Housing Corporation (CMHC)
