The Ontario Building Code | Roof Coverings
220.127.116.11. Roof Coverings
(1) Except as provided by Sentences (2) and (3), every roof covering shall have a Class A, B or C classification as determined in accordance with Article 18.104.22.168.
(2) A roof covering is not required to have a Class A, B or C classification for,
(a) a tent,
(b) an air-supported structure, or
(c) a buildingof Group A, Division 2 occupancy not more than 2 storeys in building heightand not more than 1 000 m2 in building area, provided the roof covering is underlaid with noncombustiblematerial.
(3) Combustible roof coverings on buildingswithin the scope of Article 22.214.171.124A. or 126.96.36.199A. shall have a Class A classification.