OBC DIVISION B · PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code
Section 9.30 — Flooring
Full text of Section 9.30 (Flooring) — Division B, Part 9 (Housing and Small Buildings) of the 2024 Ontario Building Code, with every article reproduced below.
9.30.1.General
9.30.1.1.Required Finished Flooring permalink →
(1) Finished flooring shall be provided in all residential occupancies.
9.30.1.2.Water Resistance permalink →
(1) Finished flooring in bathrooms, kitchens, public entrance halls, laundry and general storage areas shall consist of
resilient flooring, felted-synthetic-fibre floor coverings, concrete, terrazzo, ceramic tile, mastic or other types of flooring
providing similar degrees of water resistance. (See Note A-9.30.1.2.(1))
(1) Wood sleepers supporting finished flooring over a concrete base supported on the ground shall be not less than
19 mm by 38 mm and shall be treated with a wood preservative.
9.30.1.4.Finish Quality permalink →
(1) Finished flooring shall have a surface that is smooth, even and free from roughness or open defects.
9.30.2.Panel-Type Underlay
9.30.2.1.Required Underlay permalink →
(1) A panel-type underlay shall be provided under resilient flooring, parquet flooring, ceramic tile, felted-synthetic-fibre
floor coverings or carpeting laid over lumber subflooring. (See Sentence 9.30.3.2.(1))
(2) Panel-type underlay shall be provided under resilient flooring, parquet flooring, felted-synthetic-fibre floor
coverings or carpeting on panel-type subflooring whose edges are unsupported. (See Article 9.23.15.3.)
(3) Panel-type underlay shall be provided under ceramic tile applied with adhesive.
(4) Panel-type underlay shall be provided under resilient flooring on waferboard or strandboard subflooring.
9.30.2.2.Materials and Thickness permalink →
(1) Panel-type underlay shall be not less than 6 mm thick and shall conform to
(a) ANSI A208.1, “Particleboard,”
(b) CAN/CGSB-11.3-M, “Hardboard,”
(c) ANSI/HPVA HP-1, “American National Standard for Hardwood and Decorative Plywood,”
(d) CSA O121, “Douglas fir plywood,”
(e) CSA O151, “Canadian softwood plywood,”
(f) CSA O153, “Poplar plywood,” or
(g) CSA O437.0, “OSB and Waferboard.”
(1) Panel-type underlay shall be fastened to the subfloor with staples, annular grooved flooring nails or spiral nails,
spaced not more than 150 mm o.c. along the edges and 200 mm o.c. both ways at other locations.
(2) Nails for panel-type underlay shall be not less than 19 mm long for 6 mm thick underlay and 22 mm long for
7.9 mm thick underlay.
(3) Staples for panel-type underlay shall
(a) have not less than a 1.2 mm shank diameter or thickness with a 4.7 mm crown, and
(b) be not less than
(i) 22 mm long for 6 mm underlay, and
(ii) 28 mm long for 7.9 mm and 9.5 mm underlay.
9.30.2.4.Joints Offset permalink →
(1) Where panel-type underlay is required to be installed over plywood, OSB or waferboard, the joints in the underlay
shall be offset not less than 200 mm from the joints in the underlying subfloor.
9.30.2.5.Surface Defects permalink →
(1) Underlay beneath resilient or ceramic floors applied with an adhesive shall have all holes or open defects on the
surface patched so that the defects will not be transmitted to the finished surface.
9.30.3.Wood Strip Flooring
(1) The thickness of wood strip flooring shall conform to Table 9.30.3.1.
Table 9.30.3.1.
Thickness of Wood Strip Flooring
Forming Part of Sentence 9.30.3.1.(1)
Minimum Thickness of Flooring, mm
Type of Flooring Maximum Joist Spacing, mm
With Subfloor No Subfloor
Matched hardwood 400 7.9 19.0
(interior use only) 600 7.9 33.3
Matched softwood 400 19.0 19.0
(interior or exterior use) 600 19.0 31.7
Square edge softwood 400 — 25.4
(exterior use only) 600 — 38.1
This provision includes a table — formatting is preserved from the source; refer to the official code for the authoritative layout.
9.30.3.2.Strip Direction and End Joints permalink →
(1) Wood strip flooring shall not be laid parallel to lumber subflooring unless a separate underlay is provided.
(2) If wood strip flooring is applied without a subfloor, it shall be laid at right angles to the joists so that the end joints
are staggered and occur over supports or are end matched.
(3) If the flooring is end matched, it shall be laid so that no 2 adjoining strips break joints in the same space between
supports and each strip bears on no fewer than 2 supports.
(1) When nails are used, wood strip flooring shall be toe nailed or face nailed with not less than one nail per strip at the
spacings shown in Table 9.30.3.3., except that face nailed strips of more than 25 mm in width shall have at least 2 nails
per strip.
(2) Face nails shall be countersunk.
Table 9.30.3.3.
Nailing of Wood Strip Flooring
Forming Part of Sentence 9.30.3.3.(1)
Finish Floor Thickness, mm Minimum Length of Flooring Nails, mm Maximum Spacing of Flooring Nails, mm
7.9 38(1) 200
11.1 51 300
19.0 57 400
25.4 63 400
31.7 70 600
38.1 83 600
Notes to Table 9.30.3.3.:
(1) See Article 9.30.3.4.
This provision includes a table — formatting is preserved from the source; refer to the official code for the authoritative layout.
(1) Staples are permitted to be used to fasten wood strip flooring not more than 7.9 mm in thickness and not more than
50 mm in width provided the staples
(a) are not less than 29 mm long,
(b) have a shank diameter of not less than 1.19 mm,
(c) have a crown of not less than 4.7 mm, and
(d) are spaced not more than 400 mm o.c.
(2) Staples are permitted to be used to fasten wood strip flooring not more than 19 mm in thickness and not more than
83 mm in width provided the staples
(a) are not less than 51 mm long,
(b) have a shank diameter of not less than 1.82 mm,
(c) have a crown of not less than 12.7 mm, and
(d) are spaced not more than 400 mm o.c.
9.30.4.Parquet Flooring
(1) Adhesive used to attach parquet block flooring shall be suitable for bonding wood to the applicable subfloor
material.
9.30.5.Resilient Flooring
(1) Resilient flooring used on concrete slabs supported on ground shall consist of asphalt, rubber, unbacked vinyl or
vinyl with an inorganic type backing.
(2) Flooring described in Sentence (1) shall be attached to the base with a suitable waterproof and alkali-resistant
adhesive.
9.30.6.Ceramic Tile
(1) Ceramic tile shall be set in a mortar bed or applied to a sound smooth base with a suitable adhesive.
(2) Panel-type subfloor to which ceramic tile is to be applied with adhesive shall have its edges supported according to
Article 9.23.15.3.
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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.