The Ontario Building Code | Protection of Soffits

3.2.3.16. Protection of Soffits

(1) Except as permitted by Sentences (2) to (4), where a common attic or roof space spans more than two suites of residential occupancyor more than two patients’ or residents’ sleeping rooms in a Group B, Division 2 or 3 occupancy, and the common attic or roof space projects beyond the exterior wall of the building, the portion of any soffit or other surface enclosing the projection that is less than 2.5 m vertically above a window or door and less than 1.2 m from either side of the window or door, shall have no openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings and shall be protected by,

(a) noncombustible material,

(i) not less than 0.38 mm thick, and

(ii) having a melting point not below 650°C,

(b) not less than 12.7 mm thick gypsum soffit board or gypsum wallboard installed according to CSA A82.31-M, "gypsum Board application",

(c) not less than 11 mm thick plywood,

(d) not less than 12.5 mm thick OSB or waferboard, or

(e) not less than 11 mm thick lumber.

(2) Where an attic or roof space, including its adjoining eave overhangs, is separated by construction conforming to Article 3.1.11.7. into compartments such that the resulting spaces are not common to more than two suites of residential occupancy or more than two patients’ or residents’ sleeping rooms in a Group B, Division 2 or 3 occupancy, the requirements in Sentence (1) do not apply.

(3) If an eave overhang is completely separated from the remainder of the attic or roof space by fire blocks, the requirements of Sentence (1) do not apply.

(4) The protection required by Sentence (1) for projections is permitted to be omitted if,

(a) the fire compartments behind the window and door openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings are sprinklered in accordance with Article 3.2.5.13., and

(b) all rooms, including closets and bathrooms, having openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings in the wall beneath the soffit are sprinklered, notwithstanding exceptions permitted in the standards referenced in Article 3.2.5.13. for the installation of automatic sprinkler systems.