The Ontario Building Code | Combustible Roofing Materials
188.8.131.52. Combustible Roofing Materials
(1) Combustible roof covering that has an A, B or C classification determined in conformance with Subsection 3.1.15. is permitted on a buildingrequired to be of noncombustible construction.
(2) Combustible roof sheathing and roof sheathing supports installed above a concrete deck are permitted on a building required to be of noncombustible construction provided,
(a) the concrete deck is not less than 50 mm thick,
(b) the height of the roof space above the deck is not more than 1 000 mm,
(c) the roof space is divided into compartments by fire blocks in conformance with Article 184.108.40.206.,
(d) openings through the concrete deck, other than for noncombustible roof drains and plumbing piping, are protected by masonry or concrete shafts,
(i) constructed as fire separations having a fire-resistance rating not less than 1 h, and
(ii) extending from the concrete deck to not less than 150 mm above the adjacent roof sheathing,
(e) the perimeter of the roof is protected by a noncombustible parapet extending from the concrete deck to not less than 150 mm above the adjacent sheathing, and
(f) except as permitted by Clause (d), the roof space does not contain any buildingservices.
(3) Combustible cant strips, roof curbs, nailing strips and similar components used in the installation of roofing are permitted on a buildingrequired to be of noncombustible construction.
(4) Wood nailer facings to parapets, not more than 600 mm high, are permitted on a building required to be of noncombustible construction, if the facings and any roof membranes covering the facings are protected by sheet metal.