Support of Hearth
(1) Except as permitted in Sentence (2), the fire chamber floor and hearth shall be supported on a reinforced concrete slab not less than a 100 mm thick at its supports and, if cantilevered, not less than 50 mm thick at its unsupported edge.
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(2) A hearth for a fireplace with an opening raised not less than 200 mm from a combustible floor is permitted to be supported on that floor provided the requirements of Clauses 5.3.6.5. to 5.3.6.7. of CAN/CSA-A405-M, “Design and Construction of Masonry Chimneys and Fireplaces”, are followed.
Article 9.22.5.2 Ontario Regulation 332/12 Building Code, O. Reg. 332/12: BUILDING CODE (ontario.ca) © Queen’s Printer for Ontario, 2021
