PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code
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9.13.4.3.Providing for the Rough-in for a Subfloor Depressurization System
(See Note A-9.13.4.3.)
(1) Floors-on-ground shall be provided with a rough-in for subfloor depressurization consisting of
(a) a gas-permeable layer, an inlet and an outlet as described in Sentence (2), or
(b) clean granular material and a pipe as described in Sentence (3).
(2) The rough-in referred to in Clause (1)(a) shall include
(a) a gas-permeable layer installed in the space between the air barrier and the ground to allow the depressurization of
that space,
(b) an inlet that allows for the effective depressurization of the gas-permeable layer, and (See Note A-9.13.4.3.(2)(b) and
(3)(b)(i))
(c) an outlet in the conditioned space that
(i) permits connection to depressurization equipment,
(ii) is sealed to maintain the integrity of the air barrier system, and
(iii) is clearly labeled to indicate that it is intended only for the removal of radon from below the floor-on-ground.
(3) The rough-in referred to in Clause (1)(b) shall include
(a) clean granular material installed below the floor-on-ground in accordance with Sentence 9.16.2.1.(1), and
(b) pipe not less than 100 mm in diameter installed through the floor, such that
(i) its bottom end opens into the granular layer required in Clause (a) at or near the centre of the floor and not
less than 100 mm of granular material projects beyond the terminus of the pipe measured along its axis, (See
Note A-9.13.4.3.(2)(b) and (3)(b)(i))
(ii) its top end permits connection to depressurization equipment and is provided with an airtight cap, and
(iii) the pipe is clearly labeled near the cap and, if applicable, every 1.8 m and at every change in direction to
indicate that it is intended only for the removal of radon from below the floor-on-ground.
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Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.