CRC · California Residential Code
Cold-formed steel floor framing (prescriptive rules and tables)
If your house falls within the CRC prescriptive limits (≤60' × 40', ≤3 stories, wind <140 mph, snow ≤70 psf), pick an approved CFS joist from Table R505.3.2, space it per the table, provide the minimum bearing and track thickness, attach sheathing with No. 8 self‑drilling screws, and follow the anchorage details in Table R505.3.1(1) and the figures in § R505. If the project exceeds those limits, an engineered AISI S230 design is required.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Cold-formed steel floor framing installed prescriptively must meet the size, spacing, fastening, bearing and anchorage limits set out in § R505 of the California Residential Code. Key applicability limits (building dimensions, stories, wind and snow limits) are in § R505.1.1. Material, corrosion protection, fastener types and web‑hole rules are controlled in § R505.2 and the allowable joist spans and connection details are prescriptive in § R505.3.
The most important rule: follow the applicability limits and then use the tables and connection details in § R505 to pick joist designation, spacing, bearing length and fasteners.
Requirements in detail
Applicability limits (where the prescriptive tables apply)
- Buildings limited to not greater than 60 feet length perpendicular to joist span, not greater than 40 feet width parallel to joist span, and ≤ 3 stories above grade plane — § R505.1.1.
- Prescriptive method limited to sites with ultimate design wind speed < 140 mph (Exposure B or C) and ground snow load ≤ 70 psf — § R505.1.1.
- If a project exceeds these limits, the CRC permits design per AISI S230 instead — § R505.1.1.1.
Materials, protection and identification
- Load-bearing members must be cold‑formed from structural-quality sheet steel per § R505.2.1 and have metallic corrosion protection per § R505.2.2. Product ID requirements reference AISI S240 — § R505.2.1–R505.2.4.
Fasteners and sheathing attachment
- Screws for steel‑to‑steel connections: self‑drilling tapping screws conforming to ASTM C1513; installed with minimum edge distance and center-to-center spacing shown in § R505.2.5.
- Floor sheathing to cold‑formed joists: minimum No. 8 self‑drilling tapping screws conforming to ASTM C1513; screw head diameter and minimum edge distance requirements are in § R505.2.5.
- Gypsum ceilings attached to cold‑formed joists require No. 6 screws as specified in § R505.2.5.
Web holes and reinforcement
- Web holes must meet the conditions of AISI S230 (referenced in the CRC); nonconforming holes must be reinforced or patched per § R505.2.6.
Joist spans, bearing and minimum track thickness
- Joist size and allowable span for single or continuous spans are set by Table R505.3.2 (see simplified extracts below). Joists must have a bearing support length of not less than 1 1/2 inches for exterior wall supports and 3 1/2 inches for interior wall supports; tracks must be not less than 33 mils (0.84 mm) unless used as part of a header/trimmer per § R505.3.2.
Decision-relevant numbers (simplified extracts from Table R505.3.2)
| Joist designation | Spacing | Allowable span (30 psf live) | Allowable span (40 psf live) | Code reference |
|---|---|---|---|---|
| 550S162-33 | 16" o.c. | 10′‑4″ | 9′‑2″ | § R505.3.2 |
| 550S162-43 | 16" o.c. | 11′‑6″ | 10′‑4″ | § R505.3.2 |
| 550S162-54 | 16" o.c. | 12′‑4″ | 11′‑3″ | § R505.3.2 |
(These are representative rows from Table R505.3.2; see the full table in § R505.3.2 for more joist designations, spacings and spans.)
Floor-to-foundation / bearing‑wall anchorage
- Anchorage details and required fasteners for common framing conditions are in Table R505.3.1(1) and Figures R505.3.1(1)–(9). Example: floor joist to exterior wall track requires 2 No. 8 screws for 110 mph Exposure C (or less than 139 mph Exposure B) and 3 No. 8 screws for less than 139 mph Exposure C — see Table R505.3.1(1) and § R505.3.1.
In-line framing and trusses
- Where cold‑formed steel floors are supported by cold‑formed steel walls, joists must be located in‑line with load‑bearing studs according to tolerances in AISI S240 — § R505.1.2.
- Cold‑formed steel trusses must be designed and braced per AISI S230 and installed per § R505.1.3.
Exceptions & special cases
- Projects exceeding the dimensional, wind or snow applicability limits may use engineered design per AISI S230 in lieu of the prescriptive tables — § R505.1.1.1.
- Where Table R505.3.2 does not list a required joist designation or spacing, an engineered design is required (the CRC references AISI S230/AISI S240 for such engineered work) — see § R505.1.1.1, § R505.2.3 and § R505.2.6.
- Bearing stiffeners, lapped joists, continuous span details and cantilevers have prescriptive figures (R505.3.1(7)–(9)) — follow those figures and Table R505.3.1(2) for fastening rules where applicable — § R505.3.1 and associated figures.
If you need a special connector detail not shown in the prescriptive figures or your site conditions exceed the limits, the code explicitly defers to engineered design per the referenced AISI documents — § R505.1.1.1.
Common mistakes
- Assuming the cold‑formed prescriptive tables apply to any building: they do not — check the 60 ft / 40 ft / 3‑story / wind / snow limits in § R505.1.1.
- Using the wrong fastener type or size for steel‑to‑steel or sheathing attachment. The CRC requires ASTM C1513 self‑drilling tapping screws and specifies minimum screw numbers and locations in § R505.2.5 and Table R505.3.1(1).
- Insufficient bearing length at supports — exterior supports 1 1/2 in., interior supports 3 1/2 in. per § R505.3.2.
- Cutting or notching truss members or joists without approved design or bracing; the code prohibits altering truss members absent approved design — § R505.1.3.
- Ignoring web‑hole reinforcement rules — web holes must meet AISI S230 conditions or be reinforced/patched per § R505.2.6.
Worked example — pick a joist and verify anchorage
Scenario: Second‑floor span with uniformly distributed live load design per the CRC prescriptive live loads; you plan to use a 550S162‑43 joist at 16" o.c. and need to confirm allowable span and anchorage.
- Check applicability: Building is 30 ft × 28 ft and 2 stories — within § R505.1.1 limits (≤60 ft by 40 ft, ≤3 stories) so prescriptive method is allowed.
- Read Table R505.3.2 for 550S162‑43 @ 16" o.c.: allowable span for 30 psf live load is 11′‑6″ (for 40 psf live the allowable span is 10′‑4″) — use the correct live‑load case for your occupancy. § R505.3.2.
- Confirm bearing: Provide 3 1/2" bearing where joists sit on interior bearing walls, or 1 1/2" at exterior wall supports per § R505.3.2.
- Fasteners for sheathing: use No. 8 self‑drilling tapping screws per § R505.2.5 when attaching the floor sheathing.
- Anchorage at exterior wall (example): Table R505.3.1(1) requires 2 No. 8 screws for a floor joist to wall track connection under the 110 mph Exposure C (or less than 139 mph Exposure B) case — confirm the wind speed and exposure for your site and select the fastening shown in Table R505.3.1(1). § R505.3.1.
If your span exceeds 11′‑6″ for the chosen joist and spacing, either use a larger joist designation (refer to the full Table R505.3.2) or move to an engineered design per AISI S230.
Related provisions
- § R505.1.1 — Applicability limits for cold‑formed steel floor framing.
- § R505.2 — Material, corrosion protection, identification, fastening, web holes.
- § R505.3 — Floor construction: connections, tables, figures for bearings, laps and stiffeners.
- AISI S230 / AISI S240 — Referenced standards for prescriptive and engineered cold‑formed steel framing; the CRC defers to these where noted (§ R505.1.1.1, § R505.2.6, § R505.1.3).
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 1.1 High relevance — show source text
SECTION R505—COLD-FORMED STEEL FLOOR FRAMING
R505.1 Cold-formed steel floor framing. Elements shall be straight and free of any defects that would significantly affect structural performance. Cold-formed steel floor framing members shall be in accordance with the requirements of this section.
R505.1.1 Applicability limits. The provisions of this section shall control the construction of cold-formed steel floor framing for buildings not greater than 60 feet (18 288 mm) in length perpendicular to the joist span, not greater than 40 feet (12 192 mm) in width parallel to the joist span and less than or equal to three stories above grade plane. Cold-formed steel floor framing constructed in accordance with the provisions of this section shall be limited to sites where the ultimate design wind speed is less than 140 miles per hour (63 m/s), Exposure Category B or C, and the ground snow load is less than or equal to 70 pounds per square foot (3.35 kPa).
R505.1.1.1 Alternate applications. Cold-formed steel floor framing for buildings exceeding the applicability limits of Section R505.1.1 is permitted to be designed and constructed in accordance with AISI S230, subject to the limits therein.
R505.1.2 In-line framing. Where supported by cold-formed steel-framed walls in accordance with Section R603, cold-formed steel floor framing shall be constructed with floor joists located in-line with load-bearing studs located below the joists in accordance with the tolerances specified in AISI S240, Section B1.2.3.
R505.1.3 Floor trusses. Cold-formed steel trusses shall be designed, braced and installed in accordance with AISI S230, Section D8. In the absence of specific bracing requirements, trusses shall be braced in accordance with accepted industry practices, such as the SBCA Cold-Formed Steel Building Component Safety Information (CFSBCSI), Guide to Good Practice for Handling, Installing & Bracing of Cold-Formed Steel Trusses . Truss members shall not be notched, cut or altered in any manner without an approved design.
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R505.2 Structural framing. Load-bearing cold-formed steel floor framing members shall be in accordance with this section.
R505.2.1 Material. Load-bearing cold-formed steel framing members shall be cold formed to shape from structural quality sheet steel complying with the requirements of AISI S240, Section A3.
R505.2.2 Corrosion protection. Load-bearing cold-formed steel framing shall have a metallic coating complying with AISI S240, Section A4.
R505.2.3 Dimension, thickness and material grade. Load-bearing cold-formed steel floor framing members shall comply with AISI S230, Section A4.3 and material grade requirements as specified in AISI S230, Section A4.4.
R505.2.4 Identification. Load-bearing cold-formed steel framing members shall meet the product identification requirements of AISI S240, Section A5.5.
R505.2.5 Fastening. Screws for steel-to-steel connections shall be installed with a minimum edge distance and center-to-center spacing of [1] / 2 inch (12.7 mm), shall be self-drilling tapping, and shall conform to ASTM C1513.
CRC § 2.6 High relevance — show source text
Gypsum board ceilings shall be attached to cold-formed steel joists with minimum No. 6 screws conforming to ASTM C954 or ASTM C1513 with a bugle-head style and shall be installed in accordance with Section R702. For all connections, screws shall extend through the steel not fewer than three exposed threads. Fasteners shall have a rust-inhibitive coating suitable for the installation in which they are being used, or be manufactured from material not susceptible to corrosion.
R505.2.6 Web holes, web hole reinforcing and web hole patching. Web holes in floor framing members shall comply with the conditions as prescribed in AISI S230, Section A4.5. Web holes not in compliance with the conditions as prescribed in AISI S230, Section A4.5 shall be reinforced in accordance with the provisions of AISI S230, Section A4.6 or patched in accordance with the provisions of AISI S230, Section A4.7.
R505.3 Floor construction. Cold-formed steel floors shall be constructed in accordance with this section.
R505.3.1 Floor-to-foundation or load-bearing wall connections. Cold-formed steel-framed floors shall be anchored to foundations, wood sills or load-bearing walls in accordance with Table R505.3.1(1) and Figure R505.3.1(1), R505.3.1(2), R505.3.1(3), R505.3.1(4), R505.3.1(5) or R505.3.1(6). Anchor bolts shall be located not more than 12 inches (305 mm) from corners or the termination of bottom tracks. Continuous cold-formed steel joists supported by interior load-bearing walls shall be constructed in accordance with Figure R505.3.1(7). Lapped cold-formed steel joists shall be constructed in accordance with Figure R505.3.1(8). End floor joists constructed on foundation walls parallel to the joist span shall be doubled unless a C-shaped bearing stiffener, sized in accordance with Section R505.3.4, is installed web-to-web with the floor joist beneath each supported wall stud, as shown in Figure R505.3.1(9). Fastening of cold-formed steel joists to other framing members shall be in accordance with Section R505.2.5 and Table R505.3.1(2).
TABLE R505.3.1(1)—FLOOR-TO-FOUNDATION OR BEARING WALL CONNECTION REQUIREMENTSa, b Col2 Col3 ** FRAMING CONDITION** ** BASIC ULTIMATE WIND SPEED (mph) AND EXPOSURE** ** BASIC ULTIMATE WIND SPEED (mph) AND EXPOSURE** ** FRAMING CONDITION** ** 110 mph Exposure Category C or**
less than 139 mph Exposure Category B** Less than 139 mph Exposure Category C** Floor joist to wall track of exterior wall in accor-
dance with Figure R505.3.1(1)2-No. 8 screws 3-No. 8 screws Rim track or end joist to load-bearing wall top
track in accordance with Figure R505.3.1(1)1-No. 8 screw at 24 inches o.c. 1-No. 8 screw at 24 inches o.c. Rim track or end joist to wood sill in accordance
with Figure R505.3.1(2)Steel plate spaced at 4 feet o.c. with 4-No. CRC § 5-14 High relevance — show source text
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R505.2 Structural framing. Load-bearing cold-formed steel floor framing members shall be in accordance with this section.
R505.2.1 Material. Load-bearing cold-formed steel framing members shall be cold formed to shape from structural quality sheet steel complying with the requirements of AISI S240, Section A3.
R505.2.2 Corrosion protection. Load-bearing cold-formed steel framing shall have a metallic coating complying with AISI S240, Section A4.
R505.2.3 Dimension, thickness and material grade. Load-bearing cold-formed steel floor framing members shall comply with AISI S230, Section A4.3 and material grade requirements as specified in AISI S230, Section A4.4.
R505.2.4 Identification. Load-bearing cold-formed steel framing members shall meet the product identification requirements of AISI S240, Section A5.5.
R505.2.5 Fastening. Screws for steel-to-steel connections shall be installed with a minimum edge distance and center-to-center spacing of [1] / 2 inch (12.7 mm), shall be self-drilling tapping, and shall conform to ASTM C1513. Floor sheathing shall be attached to cold-formed steel joists with minimum No. 8 self-drilling tapping screws that conform to ASTM C1513. Screws attaching floor sheathing to cold-formed steel joists shall have a minimum head diameter of 0.292 inch (7.4 mm) with countersunk heads and shall be installed with a minimum edge distance of [3] / 8 inch (9.5 mm). Gypsum board ceilings shall be attached to cold-formed steel joists with minimum No. 6 screws conforming to ASTM C954 or ASTM C1513 with a bugle-head style and shall be installed in accordance with Section R702. For all connections, screws shall extend through the steel not fewer than three exposed threads. Fasteners shall have a rust-inhibitive coating suitable for the installation in which they are being used, or be manufactured from material not susceptible to corrosion.
R505.2.6 Web holes, web hole reinforcing and web hole patching. Web holes in floor framing members shall comply with the conditions as prescribed in AISI S230, Section A4.5. Web holes not in compliance with the conditions as prescribed in AISI S230, Section A4.5 shall be reinforced in accordance with the provisions of AISI S230, Section A4.6 or patched in accordance with the provisions of AISI S230, Section A4.7.
R505.3 Floor construction. Cold-formed steel floors shall be constructed in accordance with this section.
R505.3.1 Floor-to-foundation or load-bearing wall connections. Cold-formed steel-framed floors shall be anchored to foundations, wood sills or load-bearing walls in accordance with Table R505.3.1(1) and Figure R505.3.1(1), R505.3.1(2), R505.3.1(3), R505.3.1(4), R505.3.1(5) or R505.3.1(6). Anchor bolts shall be located not more than 12 inches (305 mm) from corners or the termination of bottom tracks.
California Residential Code High relevance — show source text
Chapter 1 Scope and Administration.
Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.
Chapter 2 Definitions.
Chapter 2 is the repository of the definitions of terms used in the body of the code. The user of the code should be familiar with and consult this chapter because the definitions are essential to the correct interpretation of the code and because the user may not be aware that a term is defined.
Chapter 3 Building Planning.
Chapter 3 provides guidelines for a minimum level of structural integrity, life safety, fire safety and livability for inhabitants of dwelling units regulated by this code. Chapter 3 is a compilation of the code requirements specific to the building planning sector of the design and construction process. This chapter sets forth code requirements dealing with light, ventilation, sanitation, minimum room size, ceiling height and environmental comfort. Chapter 3 establishes life-safety provisions including limitations on glazing used in hazardous areas, specifications on stairways, use of guards at elevated surfaces, window and fall protection, and rules for means of egress. Snow, wind and seismic design live and dead loads and flood-resistant construction, as well as solar energy systems are addressed in this chapter.
Chapter 4 Foundations.
Chapter 4 provides the requirements for the design and construction of foundation systems for buildings regulated by this code. Provisions for seismic load, flood load and frost protection are contained in this chapter. A foundation system consists of two interdependent components: the foundation structure itself and the supporting soil.
The prescriptive provisions of this chapter provide requirements for constructing footings and walls for foundations of wood, masonry, concrete and precast concrete. In addition to a foundation’s ability to support the required design loads, this chapter addresses several other factors that can affect foundation performance. These include controlling surface water and subsurface drainage, requiring soil tests where conditions warrant and evaluating proximity to slopes and minimum depth requirements. The chapter also provides requirements to minimize adverse effects of moisture, decay and pests in basements and crawl spaces.
Chapter 5 Floors.
Chapter 5 provides the requirements for the design and construction of floor systems that will be capable of supporting minimum required design loads. This chapter covers four different types: wood floor framing, wood floors on the ground, cold-formed steel floor framing and concrete slabs on the ground. Allowable span tables are provided that greatly simplify the determination of joist, girder and sheathing sizes for raised floor systems of wood framing and cold-formed steel framing. This chapter also contains prescriptive requirements for wood-framed exterior decks and their attachment to the main building.
Chapter 6 Wall Construction.
Chapter 6 contains provisions that regulate the design and construction of walls. The wall construction covered in Chapter 6 consists of five different types: wood framed, cold-formed steel framed, masonry, concrete and structural insulated panel (SIP). The primary concern of this chapter is the structural integrity of wall construction and transfer of all imposed loads to the supporting structure. This chapter provides the requirements for the design and construction of wall systems that are capable of supporting the minimum design vertical loads (dead, live and snow loads) and lateral loads (wind or seismic loads). This chapter contains the prescriptive requirements for wall bracing and/or shear walls to resist t
CRC § 1.3 High relevance — show source text
R504.1.3 Uplift and buckling. Where required, resistance to uplift or restraint against buckling shall be provided by interior bearing walls or properly designed stub walls anchored in the supporting soil below.
R504.2 Site preparation. The area within the foundation walls shall have all vegetation, topsoil and foreign material removed, and any fill material that is added shall be free of vegetation and foreign material. The fill shall be compacted to ensure uniform support of the pressure preservative-treated wood floor sleepers. R504.2.1 Base. A minimum 4-inch-thick (102 mm) granular base of gravel having a maximum size of [3] / 4 inch (19.1 mm) or crushed stone having a maximum size of [1] / 2 inch (12.7 mm) shall be placed over the compacted earth.
R504.2.2 Moisture barrier. Polyethylene sheeting of minimum 6-mil (0.15 mm) thickness shall be placed over the granular base. Joints shall be lapped 6 inches (152 mm) and left unsealed. The polyethylene membrane shall be placed over the pressure preservative-treated wood sleepers and shall not extend beneath the footing plates of the exterior walls.
R504.3 Materials. Framing materials, including sleepers, joists, blocking and plywood subflooring, shall be pressure-preservative treated and dried after treatment in accordance with AWPA U1 (Commodity Specification A, Special Requirement 4.2), and shall bear the label of an accredited agency.
SECTION R505—COLD-FORMED STEEL FLOOR FRAMING
R505.1 Cold-formed steel floor framing. Elements shall be straight and free of any defects that would significantly affect structural performance. Cold-formed steel floor framing members shall be in accordance with the requirements of this section.
R505.1.1 Applicability limits. The provisions of this section shall control the construction of cold-formed steel floor framing for buildings not greater than 60 feet (18 288 mm) in length perpendicular to the joist span, not greater than 40 feet (12 192 mm) in width parallel to the joist span and less than or equal to three stories above grade plane. Cold-formed steel floor framing constructed in accordance with the provisions of this section shall be limited to sites where the ultimate design wind speed is less than 140 miles per hour (63 m/s), Exposure Category B or C, and the ground snow load is less than or equal to 70 pounds per square foot (3.35 kPa).
R505.1.1.1 Alternate applications. Cold-formed steel floor framing for buildings exceeding the applicability limits of Section R505.1.1 is permitted to be designed and constructed in accordance with AISI S230, subject to the limits therein.
R505.1.2 In-line framing. Where supported by cold-formed steel-framed walls in accordance with Section R603, cold-formed steel floor framing shall be constructed with floor joists located in-line with load-bearing studs located below the joists in accordance with the tolerances specified in AISI S240, Section B1.2.3.
CRC § 3.1 High relevance — show source text
SHEATHING
EACH FLANGE
FIGURE R505.3.1(8)—LAPPED JOISTS SUPPORTED ON INTERIOR LOAD-BEARING WALL
TRACK
For SI: 1 inch = 25.4 mm.
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FIGURE R505.3.1(9)—BEARING STIFFENERS FOR END JOISTS
R505.3.2 Minimum floor joist sizes. Floor joist size and thickness shall be determined in accordance with the limits set forth in Table R505.3.2 for single or continuous spans. Where continuous joist members are used, the interior bearing supports shall be located within 2 feet (610 mm) of midspan of the cold-formed steel joists, and the individual spans shall not exceed the spans in Table R505.3.2. Floor joists shall have a bearing support length of not less than 1 [1] / 2 inches (38 mm) for exterior wall supports and 3 [1] / 2 inches (89 mm) for interior wall supports. Tracks shall be not less than 33 mils (0.84 mm) thick except where used as part of a floor header or trimmer in accordance with Section R505.3.8. Bearing stiffeners shall be installed in accordance with Section R505.3.4.
TABLE R505.3.2—ALLOWABLE SPANS FOR COLD-FORMED STEEL JOISTS—SINGLE OR CONTINUOUS SPANSa, b, c, d, e, f Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 JOIST DESIGNATION 30 PSF LIVE LOAD 30 PSF LIVE LOAD 30 PSF LIVE LOAD 30 PSF LIVE LOAD 40 PSF LIVE LOAD 40 PSF LIVE LOAD 40 PSF LIVE LOAD 40 PSF LIVE LOAD JOIST DESIGNATION Spacing (inches) Spacing (inches) Spacing (inches) Spacing (inches) Spacing (inches) Spacing (inches) Spacing (inches) Spacing (inches) JOIST DESIGNATION 12 ** 16** 19.2 24 12 16 19.2 24 550S162-33 11′-8″ 10′-4″ 9′-5″ 8′-5″ 10′-7″ 9′-2″ 8′-5″ 7′-6″ 550S162-43 12′-8″ 11′-6″ 10′-8″ 10′-5″ 11′-6″ 10′-4″ 9′-10″ 9′-3″ 550S162-54 13′-7″ 12′-4″ 11′-7″ 10′-9″ 12′-4″ 11′-3″ 10′ CRC § 0.42. High relevance — show source text
Portions of connections of wood-framed floor systems not noted in the figures shall be in accordance with Section R502, or AWC WFCM, if applicable. Wood framing members shall be of a species having a specific gravity equal to or greater than 0.42. 2. For floor systems of cold-formed steel construction, the provisions of Section R608.9.1 and the prescriptive details of Figures R608.9(5) through R608.9(8), where permitted by the tables accompanying those figures. Portions of connections of coldformed steel-framed floor systems not noted in the figures shall be in accordance with Section R505, or AISI S230, if applicable. 3. Proprietary connectors selected to resist loads and load combinations in accordance with Appendix A (ASD) or Appendix B (LRFD) of PCA 100. 4. An engineered design using loads and load combinations in accordance with Appendix A (ASD) or Appendix B (LRFD) of PCA 100.
- An engineered design using loads and material design provisions in accordance with this code, or in accordance with ASCE 7, ACI 318, and AWC NDS for wood-framed construction or AISI S100 for cold-formed steel frame construction.
R608.9.3 Connections between concrete walls and light-frame ceiling and roof systems. Connections between concrete walls and light-frame ceiling and roof systems shall be in accordance with one of the following:
- For ceiling and roof systems of wood-framed construction, the provisions of Section R608.9.1 and the prescriptive details of Figures R608.9(9) and R608.9(10), where permitted by the tables accompanying those figures. Portions of connections of wood-framed ceiling and roof systems not noted in the figures shall be in accordance with Section R802, or AWC WFCM, if applicable. Wood framing members shall be of a species having a specific gravity equal to or greater than 0.42.
- For ceiling and roof systems of cold-formed steel construction, the provisions of Section R608.9.1 and the prescriptive details of Figures R608.9(11) and R608.9(12), where permitted by the tables accompanying those figures. Portions of
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connections of cold-formed steel-framed ceiling and roof systems not noted in the figures shall be in accordance with Section R804, or AISI S230, if applicable. 3. Proprietary connectors selected to resist loads and load combinations in accordance with Appendix A (ASD) or Appendix B (LRFD) of PCA 100. 4. An engineered design using loads and load combinations in accordance with Appendix A (ASD) or Appendix B (LRFD) of PCA 100.
- An engineered design using loads and material design provisions in accordance with this code, or in accordance with ASCE 7, ACI 318, and AWC NDS for wood-framed construction or AISI S100 for cold-formed steel-framed construction.
CRC § 3.1 High relevance — show source text
FIGURE R505.3.1(6)—CANTILEVERED FLOOR TO EXTERIOR LOAD-BEARING WALL CONNECTION
BLOCKING EVERY OTHER JOIST
WEB STIFFENER
RIM TRACK (MIN. 33 MIL THICK)
NO. 8 SCREWS THROUGH FLANGE, CLIP ANGLE OR BENT STIFFENER
CONNECTION OF BLOCKING
TO JOIST THROUGH EACH
LEG OF WEB STIFFENER OR
CLIP ANGLE WITH 2 NO. 8
SHEATHING
JOIST
TOP TRACK
LOAD-BEARING STUD
For SI: 1 mil = 0.0254 mm.
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FIGURE R505.3.1(7)—CONTINUOUS SPAN JOIST SUPPORTED ON INTERIOR LOAD-BEARING WALL
CONNECTION OF BLOCKING
JOIST
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm.
SHEATHING
EACH FLANGE
FIGURE R505.3.1(8)—LAPPED JOISTS SUPPORTED ON INTERIOR LOAD-BEARING WALL
TRACK
For SI: 1 inch = 25.4 mm.
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FIGURE R505.3.1(9)—BEARING STIFFENERS FOR END JOISTS
R505.3.2 Minimum floor joist sizes. Floor joist size and thickness shall be determined in accordance with the limits set forth in Table R505.3.2 for single or continuous spans. Where continuous joist members are used, the interior bearing supports shall be located within 2 feet (610 mm) of midspan of the cold-formed steel joists, and the individual spans shall not exceed the spans in Table R505.3.2. Floor joists shall have a bearing support length of not less than 1 [1] / 2 inches (38 mm) for exterior wall supports and 3 [1] / 2 inches (89 mm) for interior wall supports. Tracks shall be not less than 33 mils (0.84 mm) thick except where used as part of a floor header or trimmer in accordance with Section R505.3.8. Bearing stiffeners shall be installed in accordance with Section R505.3.4.
|TABLE R505.3.2—ALLOWABLE SPANS FOR COLD-FORMED STEEL JOISTS—SINGLE OR CONTINUOUS SPANSa, b, c, d, e,
CRC § 5-1 Medium relevance — show source text
The state agency does not adopt sections identified with the following symbol: †
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5 FLOORS
User notes:
About this chapter: Chapter 5 provides the requirements for the design and construction of floor systems that will be capable of supporting minimum required design loads. This chapter covers wood floor framing, wood floors on the ground, cold-formed steel floor framing and concrete slabs on the ground. Allowable span tables are provided that greatly simplify the determination of joist, girder and sheathing sizes for raised floor systems of wood framing and cold-formed steel framing. This chapter also contains prescriptive requirements for wood-framed exterior decks and their attachment to the main building.
SECTION R501—GENERAL
R501.1 Application. The provisions of this chapter shall control the design and construction of the floors for buildings, including the floors of attic spaces used to house mechanical or plumbing fixtures and equipment.
R501.2 Requirements. Floor construction shall be capable of accommodating all loads in accordance with Section R301 and of transmitting the resulting loads to the supporting structural elements.
SECTION R502—WOOD FLOOR FRAMING
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.
R502.1.1.1 Preservative-treated lumber. Preservative treated dimension lumber shall be identified as required by Section R304.2.
R502.1.1.2 End-jointed lumber. Approved end-jointed lumber identified by a grade mark conforming to Section R502.1.1 shall be permitted to be used interchangeably with solid-sawn members of the same species and grade. End-jointed lumber used in an assembly required elsewhere in this code to have a fire-resistance rating shall have the designation “Heat-Resistant Adhesive” or “HRA” included in its grade mark.
R502.1.2 Prefabricated wood I-joists. Structural capacities and design provisions for prefabricated wood I-joists shall be established and monitored in accordance with ASTM D5055.
R502.1.3 Structural glued-laminated timbers. Glued-laminated timbers shall be manufactured and identified as required in ANSI A190.1, ANSI 117 and ASTM D3737.
R502.1.4 Structural log members. Structural log members shall comply with the provisions of ICC 400.
R502.1.5 Structural composite lumber. Structural capacities for structural composite lumber shall be established and monitored in accordance with ASTM D5456.
R502.1.6 Cross-laminated timber. Cross-laminated timber shall be manufactured and identified as required by ANSI/APA PRG 320.
CRC § 4-6 Medium relevance — show source text
R403 Footings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
R404 Foundation and Retaining Walls . . . . . . . . . . . . . . . . 4-24
R405 Foundation Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42
R406 Foundation Waterproofing and Dampproofing . . . 4-43
R407 Columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-44
R408 Under-Floor Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-44
CHAPTER 5 FLOORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
R501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
R502 Wood Floor Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
R503 Floor Sheathing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
R504 Pressure Preservative-Treated Wood
Floors (On Ground) . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
R505 Cold-Formed Steel Floor Framing . . . . . . . . . . . . . . . 5-14
R506 Concrete Floors (On Ground) . . . . . . . . . . . . . . . . . . . 5-26
R507 Exterior Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26
CHAPTER 6 WALL CONSTRUCTION. . . . . . . . . . . . . . . . . . . 6-3
R601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
R602 Wood Wall Framing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
R603 Cold-Formed Steel Wall Framing. . . . . . . . . . . . . . . . 6-53
R604 Wood Structural Panels . . . . . . . . . . . . . . . . . . . . . . . . 6-93
R605 Particleboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-93
R606 General Masonry Construction. . . . . . . . . . . . . . . . . . 6-93
CRC § 5-14 Medium relevance — show source text
Floors (On Ground) . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
R505 Cold-Formed Steel Floor Framing . . . . . . . . . . . . . . . 5-14
R506 Concrete Floors (On Ground) . . . . . . . . . . . . . . . . . . . 5-26
R507 Exterior Decks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26
CHAPTER 6 WALL CONSTRUCTION. . . . . . . . . . . . . . . . . . . 6-3
R601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
R602 Wood Wall Framing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
R603 Cold-Formed Steel Wall Framing. . . . . . . . . . . . . . . . 6-53
R604 Wood Structural Panels . . . . . . . . . . . . . . . . . . . . . . . . 6-93
R605 Particleboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-93
R606 General Masonry Construction. . . . . . . . . . . . . . . . . . 6-93
R607 Glass Unit Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-106
R608 Exterior Concrete Wall Construction. . . . . . . . . . . . 6-107
R609 Exterior Windows and Doors. . . . . . . . . . . . . . . . . . . 6-172
R610 Structural Insulated Panel Wall Construction . . . 6-175
CHAPTER 7 WALL COVERING. . . . . . . . . . . . . . . . . . . . . . . . 7-3
R701 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
R702 Interior Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
R703 Exterior Wall Covering . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
R704 Exterior Soffits and Fascias. . . . . . . . . . . . . . . . . . . . . 7-32
R705 BIPV Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-35
CHAPTER 8 ROOF-CEILING CONSTRUCTION. . . . . . . . . . . 8-3
CRC § 9.1.1 Medium relevance — show source text
R608.9.1.1 Anchor bolts. Anchor bolts used to connect light-frame floor, ceiling and roof systems to concrete walls in accordance with Figures R608.9(1) through R608.9(12) shall have heads, or shall be rods with threads on both ends with a hex or square nut on the end embedded in the concrete. Bolts and threaded rods shall comply with Section R608.5.2.2. Anchor bolts with J- or L-hooks shall not be used where the connection details in these figures are used.
R608.9.1.2 Removal of stay-in-place form material at bolts. Holes in stay-in-place forms for installing bolts for attaching facemounted wood ledger boards to the wall shall be not less than 4 inches (102 mm) in diameter for forms not greater than 1 [1] / 2 inches (38 mm) in thickness, and increased 1 inch (25 mm) in diameter for each [1] / 2 -inch (12.7 mm) increase in form thickness. Holes in stayin-place forms for installing bolts for attaching face-mounted cold-formed steel tracks to the wall shall be not less than 4 inches (102 mm) square. The wood ledger board or steel track shall be in direct contact with the concrete at each bolt location. Exception: A vapor retarder or other material less than or equal to [1] / 16 inch (1.6 mm) in thickness is permitted to be installed between the wood ledger or cold-formed track and the concrete.
R608.9.2 Connections between concrete walls and light-frame floor systems. Connections between concrete walls and lightframe floor systems shall be in accordance with one of the following:
For floor systems of wood-framed construction, the provisions of Section R608.9.1 and the prescriptive details of Figures R608.9(1) through R608.9(4), where permitted by the tables accompanying those figures. Portions of connections of wood-framed floor systems not noted in the figures shall be in accordance with Section R502, or AWC WFCM, if applicable. Wood framing members shall be of a species having a specific gravity equal to or greater than 0.42.
For floor systems of cold-formed steel construction, the provisions of Section R608.9.1 and the prescriptive details of Figures R608.9(5) through R608.9(8), where permitted by the tables accompanying those figures. Portions of connections of coldformed steel-framed floor systems not noted in the figures shall be in accordance with Section R505, or AISI S230, if applicable.
Proprietary connectors selected to resist loads and load combinations in accordance with Appendix A (ASD) or Appendix B (LRFD) of PCA 100.
An engineered design using loads and load combinations in accordance with Appendix A (ASD) or Appendix B (LRFD) of PCA 100.
An engineered design using loads and material design provisions in accordance with this code, or in accordance with ASCE 7, ACI 318, and AWC NDS for wood-framed construction or AISI S100 for cold-formed steel frame construction.
R608.9.3 Connections between concrete walls and light-frame ceiling and roof systems. Connections between concrete walls and light-frame ceiling and roof systems shall be in accordance with one of the following:
- For ceiling and roof systems of wood-framed construction, the provisions of Section R608.9.1 and the prescriptive details of Figures R608.9(9) and R608.9(10), where permitted by the tables accompanying those figures.
Frequently asked questions
What is the single most important check before using the prescriptive tables?
Confirm the project meets the applicability limits (≤ 60 ft by 40 ft, ≤ 3 stories, wind and snow limits) in § R505.1.1; if not, the prescriptive tables do not apply.
Which screw type must I use for attaching floor sheathing to cold‑formed steel joists?
Use No. 8 self‑drilling tapping screws conforming to ASTM C1513, as required by § R505.2.5.
Where are allowable joist spans listed?
Allowable spans for joist designations, spacings and live‑load cases are in Table R505.3.2 (see § R505.3.2).
What bearing length must I provide at supports?
Provide at least 1 1/2 in. bearing at exterior wall supports and 3 1/2 in. at interior wall supports per § R505.3.2.
Can I cut or notch cold‑formed steel truss members?
No — truss members must not be notched, cut or altered without an approved design; see § R505.1.3.
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