Section R502 — WOOD FLOOR FRAMING
2025 California Residential Code (Title 24, Part 2.5) · 2025 edition · ingested 2026-07-07 · California
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R502.1 General. ¶
R502.1 General. Wood and wood-based products used for load-supporting purposes shall conform to the applicable provisions of this section. R502.1.1 Sawn lumber. Sawn lumber shall be identified by a grade mark of an accredited lumber grading or inspection agency and have design values certified by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted. Note: See Section R301.1.1.1 for limited-density owner- built rural dwellings.…
R502.2 Design and construction. ¶
R502.2 Design and construction. Floors shall be designed and constructed in accordance with the provisions of this chapter, Figure R502.2 and Sections R304 and R305 or in accordance with ANSI AWC NDS. on Jul 18, 2025 11:14 AM (CDT) THEREUNDER. FLOORS FIGURE R502.2—FLOOR CONSTRUCTION SILL PLATE BAND, RIM OR HEADER JOIST BOTTOM WALL STUDS PLATE OPTIONAL FINISH FLOOR SUBFLOOR OR FLOOR SHEATHING– JOISTS–SEE TABLES SEE SECTION R503 R502.3.1(1) AND R502.3.1(2) Col1Col2Col3Col4Col5Col6Col7Col8Col9Col10Col11Col12Col13Col14Col15 --------------------------------------------- 2 IN. CLEARANCE SEE SECTION…
R502.3 Allowable joist spans. ¶
R502.3 Allowable joist spans. Spans for floor joists shall be in accordance with Tables R502.3.1(1) and R502.3.1(2). For other grades and species and for other loading conditions, refer to the AWC STJR. 5-4 2025 CALIFORNIA RESIDENTIAL CODE on Jul 18, 2025 11:14 AM (CDT) THEREUNDER. FLOORS R502.3.1 Sleeping areas and attic joists. Table R502.3.1(1) shall be used to determine the maximum allowable span of floor joists that support sleeping areas and attics that are accessed by means of a fixed stairway in accordance with Section R318.7 provided that the design live load does not exceed 30…
R502.4 Joists under bearing partitions. ¶
R502.4 Joists under bearing partitions. Joists under parallel bearing partitions shall be of adequate size to support the load. Double joists, sized to adequately support the load, that are separated to permit the installation of piping or vents shall be full-depth solid blocked with lumber not less than 2 inches (51 mm) in nominal thickness spaced not more than 4 feet (1219 mm) on center. Bearing partitions perpendicular to joists shall not be offset from supporting girders, walls or partitions more than the joist depth unless such joists are of sufficient size to carry the additional load.…
R502.5 Allowable girder and header spans. ¶
R502.5 Allowable girder and header spans. The allowable spans of girders and headers fabricated of dimension lumber shall not exceed the values set forth in Tables R602.7(1), R602.7(2) and R602.7(3).
R502.6 Bearing. ¶
R502.6 Bearing. The ends of each joist, beam or girder shall have not less than 1 [1] / 2 inches (38 mm) of bearing on wood or metal, have not less than 3 inches of bearing (76 mm) on masonry or concrete or be supported by approved joist hangers. Alternatively, the ends of joists shall be supported on a 1-inch by 4-inch (25 mm by 102 mm) ribbon strip and shall be nailed to the adjacent stud. The bearing on masonry or concrete shall be direct, or a sill plate of 2-inch-minimum (51 mm) nominal thickness shall be provided under the joist, beam or girder. The sill plate shall provide a minimum…
R502.7 Lateral restraint at supports. ¶
R502.7 Lateral restraint at supports. Joists shall be supported laterally at the ends by full-depth solid blocking not less than 2 inches (51 mm) nominal in thickness; or by attachment to a full-depth header, band or rim joist, or to an adjoining stud or shall be otherwise provided with lateral support to prevent rotation. Exceptions: 1. Trusses, structural composite lumber, structural glued-laminated members and I-joists shall be supported laterally as required by the manufacturer’s recommendations. 2. In Seismic Design Categories D 0, D 1 and D 2, lateral restraint shall be provided at each…
R502.8 Cutting, drilling and notching. ¶
R502.8 Cutting, drilling and notching. Structural floor members shall not be cut, bored or notched in excess of the limitations specified in this section. See Figure R502.8. FIGURE R502.8—CUTTING, NOTCHING AND DRILLING Col1Col2Col3Col4Col5Col6 ------------------ D/4 MAX.D/4 MAX.D/4 MAX.D/4 MAX. PIPE OR CONDUIT D D/3 MAX. FLOOR JOIST— END CUTS 2 IN. MIN. FROM TOP AND BOTTOM OF JOIST For SI: 1 inch = 25.4 mm. 5-10 2025 CALIFORNIA RESIDENTIAL CODE on Jul 18, 2025 11:14 AM (CDT) THEREUNDER. FLOORS R502.8.1 Sawn lumber. Notches in solid lumber joists, rafters and beams shall not exceed one-sixth…
R502.9 Fastening. ¶
R502.9 Fastening. Floor framing shall be nailed in accordance with Table R602.3(1). Where posts and beam or girder construction is used to support floor framing, positive connections shall be provided to ensure against uplift and lateral displacement.
R502.10 Framing of openings. ¶
R502.10 Framing of openings. Openings in floor framing shall be framed with header and trimmer joists. Where the header joist span does not exceed 4 feet (1219 mm), the header joist shall be a single member the same size as the floor joist. Single trimmer joists shall be used to carry a single header joist that is located within 3 feet (914 mm) of the trimmer joist bearing. Where the header joist span exceeds 4 feet (1219 mm), the trimmer joists and the header joist shall be doubled and of sufficient cross section to support the floor joists framing into the header.
R502.11 Floor framing supporting guards. ¶
R502.11 Floor framing supporting guards. The framing at the open edge of a floor supporting a required guard assembly shall be constructed in accordance with Section R502.11.1 or R502.11.2 for guard assemblies not exceeding 44 inches (1118 mm) in height, or shall be designed in accordance with accepted engineering practice to support the guard assembly. Where trusses and I-joists are used as edge framing members supporting guards, the effects of the guard loads shall be specifically considered in the design of the edge member. R502.11.1 Conventional edge framing. Where a roll brace is aligned…
R502.12 Wood trusses. ¶
R502.12 Wood trusses. R502.12.1 Design. Wood trusses shall be designed in accordance with approved engineering practice. The design and manufacture of metal-plate-connected wood trusses shall comply with ANSI/TPI 1. The truss design drawings shall be prepared by a registered design professional. R502.12.2 Bracing. Trusses shall be braced to prevent rotation and provide lateral stability in accordance with the requirements specified in the construction documents for the building and on the individual truss design drawings. In the absence of specific bracing requirements, trusses shall be…
R502.13 Draftstopping required. ¶
R502.13 Draftstopping required. Draftstopping shall be provided in accordance with Section R302.12.
R502.14 Fireblocking required. ¶
R502.14 Fireblocking required. Fireblocking shall be provided in accordance with Section R302.11.