CRC · California Residential Code
What limits apply to drilling, notching and cutting studs?
The CRC restricts how much of a stud you can remove: exterior/bearing studs may be notched up to 25% of their depth and bored holes over 40% require the stud be doubled (nonbearing studs allow deeper notches and larger holes up to 60%); keep holes ≥ 5/8" from the edge and follow the top-plate reinforcement rule when over half the plate width is cut (see § R602.6 and § R602.6.1).
Last reviewed: July 6, 2026
What the code requires — plain English
Drills, notches and cuts in wall studs are limited to protect the stud’s load capacity and wall integrity. The controlling rule is § R602.6 of the California Residential Code: exterior and bearing studs may be notched up to 25% of their depth and bored/holed up to 40% (unless doubled); nonbearing partition studs may be notched up to 40% and bored up to 60% of stud depth. Top plates that are cut more than 50% of their width have a specific reinforcing requirement under § R602.6.1.
The single most important rule: do not remove more than the allowed fraction of a stud’s depth (25% for exterior/bearing; 40% for nonbearing notches), and keep bored holes at least 5/8 inch from the stud edge. § R602.6 governs these limits.
Requirements in detail
Notching (cuts removed from the face of a stud)
- A stud in an exterior wall or bearing partition shall not be cut or notched to a depth exceeding 25% of its depth. § R602.6.
- Studs in nonbearing partitions shall not be notched to a depth exceeding 40% of a single stud depth. § R602.6.
Boring (circular holes)
- The diameter of bored holes in studs shall not exceed 60% of the stud depth (general limit stated in the section), but there are specific limits for exterior/bearing studs. § R602.6.
- The edge of any bored hole must be at least 5/8 inch (≈16 mm) from the edge of the stud. § R602.6.
- A bored hole must not be located in the same cross section of a stud as a cut or notch. § R602.6.
- For studs in exterior walls or bearing partitions, bored-hole diameters over 40% of stud depth require that the stud be doubled, and no more than two successive doubled studs may be so bored. § R602.6.
Top plates
- If piping or ductwork requires cutting/drilling/notching of a top plate in an exterior wall or interior load-bearing wall by more than 50% of the plate width, a galvanized metal tie (minimum 0.054 in / 16 ga thick and 1.5 in wide) must be fastened across the plate at each side of the opening with not less than eight 10d nails at each side (tie to extend not less than 6 inches past the opening). This requirement is in § R602.6.1.
- Exception: the metal-tie requirement is waived where the entire side of the wall with the notch/cut is covered by wood structural panel sheathing. § R602.6.1.
Manufacturer alternatives
- Where approved, stud shoes installed per the manufacturer’s instructions may be used as an alternative for some conditions referenced in § R602.6.
Quick reference table (decision-relevant dimensions / values)
| Action / limit | Threshold / value | Key note | Code Reference |
|---|---|---|---|
| Notch depth — exterior / bearing stud | 25% of stud depth | Applies to any cut/notch in exterior or bearing partition studs | § R602.6 |
| Notch depth — nonbearing partition stud | 40% of stud depth | Applies to single (nonbearing) studs only | § R602.6 |
| Bored hole diameter — general maximum | 60% of stud depth | Upper limit in section; contextual limits differ by wall type | § R602.6 |
| Bored hole diameter — exterior / bearing | ≤ 40% normally; >40% and ≤60% allowed only if stud doubled | If hole >40% in exterior/bearing stud, the stud must be doubled; not more than two successive doubled studs may be so bored | § R602.6 |
| Minimum distance from hole edge to stud edge | 5/8 inch (≈16 mm) | Applies to all bored holes | § R602.6 |
| Hole and notch location | Must not be in the same cross section | Never place a bored hole in the same section as a cut or notch | § R602.6 |
| Top plate cut/drill > width | >50% of plate width triggers reinforcement | Requires 16 ga × 1.5 in metal tie, 8–10d nails each side, tie extend 6 in past opening; exception if wood structural panel sheathing covers entire wall side | § R602.6.1 |
| Approved stud-shoe alternative | As allowed by manufacturer | Must be installed per manufacturer's instructions | § R602.6 (Exception) |
Exceptions & special cases
- Approved stud shoes may be used instead of doubling or other reinforcement when installed per manufacturer instructions (exception in § R602.6).
- The top-plate metal-tie requirement (for >50% width cuts) does not apply if the entire side of the wall with the notch/cut is covered by wood structural panel sheathing. § R602.6.1.
- Where other code sections or a registered design professional apply (e.g., engineered assemblies, or buildings in certain seismic categories or taller than three stories), the cutting/notching/boring of studs may be governed by different or additional design requirements; see Related Provisions below for those sections. (See also CBC cross-references in the documents.)
Common mistakes
- Assuming the 60% bored-hole limit applies to exterior/bearing studs without applying the doubling / successive-studs rule — for exterior/bearing studs, holes over 40% trigger doubling and limits on successive doubled studs. § R602.6.
- Placing a bored hole within 5/8 in of the stud edge or in the same cross section as a notch — both are prohibited. § R602.6.
- Cutting more than 50% of a top plate and not installing the required metal tie (or checking the sheathing exception). § R602.6.1.
- Modifying engineered studs or members without following the manufacturer’s instructions or a registered design professional’s directions (other CRC/CBC sections address engineered products—see Related Provisions).
Worked example — apply the rule with numbers
Scenario: You need to run a 2-inch pipe through a common 2×4 exterior wall stud.
- Typical actual depth of a 2×4 is 3.5 inches (this common lumber dimension is not specified in § R602.6; the CRC limits use the stud’s depth). The code text itself does not list nominal actual depths, so verify the actual member depth you’re working with. (CRC text: § R602.6.)
- Notching: Max notch depth in an exterior/bearing stud = 25% of 3.5 in = 0.875 in. You must not cut a notch deeper than about 7/8 inch. § R602.6.
- Boring: Diameter allowed in exterior/bearing stud without doubling = ≤ 40% of 3.5 in = 1.4 in. A 2-inch pipe would require a hole larger than 1.4 in, so you cannot place a 2 in hole in a single exterior/bearing 2×4 stud unless you follow the doubling rule.
- Doubling option: If you bore a hole >40% and ≤60% (i.e., up to 60% of 3.5 in = 2.1 in) in an exterior/bearing stud, the stud must be doubled, and you may not have more than two successive doubled studs so bored. § R602.6.
- Minimum edge distance: the hole edge must be at least 5/8 in from the stud face/edge. § R602.6. Practical outcome: to run a 2 in pipe through this exterior/bearing stud you would either (a) double the stud and ensure not more than two successive doubled studs are bored, keep the hole edge ≥ 5/8 in, or (b) reroute the pipe or use framing alternatives approved by the code/manufacturer. § R602.6.
Related provisions (useful cross-references)
- Cutting, drilling and notching of structural floor members — § R502.8 (limits for joists, holes, relation to notches).
- Drilling and notching of top plate — § R602.6.1 (metal tie requirement for >50% cuts).
- Engineered wood products restrictions (do not cut/notch except per manufacturer or RDP design) — § R502.8.2 / § R802.7.2 (roof/ceiling) and related provisions.
- Parallel provisions in the California Building Code for dimensional wood framing — § 2308.6.2 – 2308.6.3 (wall studs and bored holes rules in CBC chapter that align with CRC requirements).
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 1.2. High relevance — show source text
- Where the net uplift value at the top of a wall exceeds 100 plf (146 N/mm), installing approved uplift framing connectors to provide a continuous load path from the top of the wall to the foundation or to a point where the uplift force is 100 plf (146 N/mm) or less. The net uplift value shall be as determined in Item 1.2.
- Wall sheathing and fasteners designed to resist combined uplift and shear forces in accordance with accepted engineering practice.
R602.4 Interior load-bearing walls. Interior load-bearing walls shall be constructed, framed and fireblocked as specified for exterior walls.
R602.5 Interior nonbearing walls. Interior nonbearing walls shall be permitted to be constructed with 2-inch by 3- inch (51 mm by 76 mm) studs spaced 24 inches (610 mm) on center or, where not part of a braced wall line, 2-inch by 4- inch (51 mm by 102 mm) flat studs spaced at 16 inches (406 mm) on center. Interior nonbearing walls shall be capped with not less than a single top plate. Interior nonbearing walls shall be fireblocked in accordance with Section R602.8.
R602.6 Drilling and notching of studs. Drilling and notching of studs shall be in accordance with the following:
- Notching. A stud in an exterior wall or bearing partition shall not be cut or notched to a depth exceeding 25 percent of its depth. Studs in nonbearing partitions shall not be notched to a depth exceeding 40 percent of a single stud depth.
- Boring. The diameter of bored holes in studs shall not exceed 60 percent of the stud depth, the edge of the hole shall not be less than [5] / 8 inch (16 mm) from the edge of the stud, and the hole shall not be located in the same section as a cut or notch. Where the diameter of a bored hole in a stud located in exterior walls or bearing partitions is over 40 percent, such stud shall be doubled and not more than two successive doubled studs shall be so bored. See Figures R602.6(1) and R602.6(2).
Exception: Where approved, stud shoes are installed in accordance with the manufacturer’s instructions.
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WALL CONSTRUCTION
FIGURE R602.6(1)—NOTCHING AND BORED HOLE LIMITATIONS FOR EXTERIOR WALLS AND BEARING WALLS
TOP PLATES
STUD
BORED HOLE MAX. DIAMETER 40 PERCENT OF STUD DEPTH
5 / 8 IN. MIN. TO EDGE
5 / 8 IN. MIN. TO EDGE
NOTCH MUST NOT EXCEED 25 PERCENT OF STUD DEPTH
BORED HOLES SHALL NOT BE LOCATED IN THE SAME CROSS SECTION OF CUT OR NOTCH IN STUD
For SI: 1 inch = 25.4 mm. Note: Condition for exterior and bearing walls.
IF HOLE IS BETWEEN 40 PERCENT AND 60 PERCENT OF STUD DEPTH, THEN STUD MUST BE DOUBLE AND NO MORE THAN TWO SUCCESSIVE STUDS ARE DOUBLED AND SO
2025 CALIFORNIA RESIDENTIAL CODE 6-15
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CRC § 25.4 High relevance — show source text
STUD
BORED HOLE MAX. DIAMETER 60 PERCENT OF STUD DEPTH
5 / 8 IN. MIN. TO EDGE
5 / 8 IN. MIN. TO EDGE
NOTCH MUST NOT EXCEED 40 PERCENT OF STUD DEPTH
BORED HOLES SHALL NOT BE LOCATED IN THE SAME CROSS SECTION OF CUT OR NOTCH IN STUD
For SI: 1 inch = 25.4 mm.
R602.6.1 Drilling and notching of top plate. Where piping or ductwork is placed in or partly in an exterior wall or interior loadbearing wall, necessitating cutting, drilling or notching of the top plate by more than 50 percent of its width, a galvanized metal tie not less than 0.054 inch thick (1.37 mm) (16 ga) and 1 [1] / 2 inches (38 mm) wide shall be fastened across and to the plate at each side of the opening with not less than eight 10d (0.148 inch diameter) nails having a minimum length of 1 [1] / 2 inches (38 mm) at each side or equivalent. The metal tie must extend not less than 6 inches past the opening. See Figure R602.6.1.
Exception: Where the entire side of the wall with the notch or cut is covered by wood structural panel sheathing.
FIGURE R602.6.1—TOP PLATE FRAMING TO ACCOMMODATE PIPING
EXTERIOR OR BEARING WALL
NOTCH GREATER THAN 50
16 GAGE (0.054 IN.) AND 1.5 IN. WIDE METAL TIE FASTENED ACROSS AND TO THE PLATE AT EACH SIDE OF THE NOTCH WITH 8-10d NAILS EACH SIDE
For SI: 1 inch = 25.4 mm.
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R602.7 Headers. For header spans, see Tables R602.7(1), R602.7(2) and R602.7(3).
TABLE R602.7(1)—GIRDER SPANSa AND HEADER SPANSa FOR EXTERIOR BEARING WALLS
(Maximum spans for Douglas fir-larch, hem-fir, Southern pine and spruce-pine-firb and required number of jack studs)Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17 Col18 Col19 Col20 ** GIRDERS**
AND HEADERS
SUPPORTING** SIZE** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e ** ** GROUND SNOW LOAD (psf)e CRC § 6-14 High relevance — show source text
Where the diameter of a bored hole in a stud located in exterior walls or bearing partitions is over 40 percent, such stud shall be doubled and not more than two successive doubled studs shall be so bored. See Figures R602.6(1) and R602.6(2).
Exception: Where approved, stud shoes are installed in accordance with the manufacturer’s instructions.
6-14 2025 CALIFORNIA RESIDENTIAL CODE
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WALL CONSTRUCTION
FIGURE R602.6(1)—NOTCHING AND BORED HOLE LIMITATIONS FOR EXTERIOR WALLS AND BEARING WALLS
TOP PLATES
STUD
BORED HOLE MAX. DIAMETER 40 PERCENT OF STUD DEPTH
5 / 8 IN. MIN. TO EDGE
5 / 8 IN. MIN. TO EDGE
NOTCH MUST NOT EXCEED 25 PERCENT OF STUD DEPTH
BORED HOLES SHALL NOT BE LOCATED IN THE SAME CROSS SECTION OF CUT OR NOTCH IN STUD
For SI: 1 inch = 25.4 mm. Note: Condition for exterior and bearing walls.
IF HOLE IS BETWEEN 40 PERCENT AND 60 PERCENT OF STUD DEPTH, THEN STUD MUST BE DOUBLE AND NO MORE THAN TWO SUCCESSIVE STUDS ARE DOUBLED AND SO
2025 CALIFORNIA RESIDENTIAL CODE 6-15
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WALL CONSTRUCTION
FIGURE R602.6(2)—NOTCHING AND BORED HOLE LIMITATIONS FOR INTERIOR NONBEARING WALLS
TOP PLATES
STUD
BORED HOLE MAX. DIAMETER 60 PERCENT OF STUD DEPTH
5 / 8 IN. MIN. TO EDGE
5 / 8 IN. MIN. TO EDGE
NOTCH MUST NOT EXCEED 40 PERCENT OF STUD DEPTH
BORED HOLES SHALL NOT BE LOCATED IN THE SAME CROSS SECTION OF CUT OR NOTCH IN STUD
For SI: 1 inch = 25.4 mm.
R602.6.1 Drilling and notching of top plate. Where piping or ductwork is placed in or partly in an exterior wall or interior loadbearing wall, necessitating cutting, drilling or notching of the top plate by more than 50 percent of its width, a galvanized metal tie not less than 0.054 inch thick (1.37 mm) (16 ga) and 1 [1] / 2 inches (38 mm) wide shall be fastened across and to the plate at each side of the opening with not less than eight 10d (0.148 inch diameter) nails having a minimum length of 1 [1] / 2 inches (38 mm) at each side or equivalent. The metal tie must extend not less than 6 inches past the opening. See Figure R602.6.1.
Exception: Where the entire side of the wall with the notch or cut is covered by wood structural panel sheathing.
FIGURE R602.6.1—TOP PLATE FRAMING TO ACCOMMODATE PIPING
EXTERIOR OR BEARING WALL
NOTCH GREATER THAN 50
16 GAGE (0.054 IN.) AND 1.5 IN. WIDE METAL TIE FASTENED ACROSS AND TO THE PLATE AT EACH SIDE OF THE NOTCH WITH 8-10d NAILS EACH SIDE
CRC § 7.1 High relevance — show source text
R502.7.1 Bridging. Joists exceeding a nominal 2 inches by 12 inches (51 mm by 305 mm) shall be supported laterally by solid blocking, diagonal bridging (wood or metal), or a continuous 1-inch by 3-inch (25 mm by 76 mm) strip nailed across the bottom of joists perpendicular to joists at intervals not exceeding 8 feet (2438 mm).
Exception: Trusses, structural composite lumber, structural glued-laminated members and I-joists shall be supported laterally as required by the manufacturer’s recommendations.
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
Col1 Col2 Col3 Col4 Col5 Col6 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.
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R502.8.1 Sawn lumber. Notches in solid lumber joists, rafters and beams shall not exceed one-sixth of the depth of the member, shall not be longer than one-third of the depth of the member and shall not be located in the middle one-third of the span. Notches at the ends of the member shall not exceed one-fourth the depth of the member. The tension side of members 4 inches (102 mm) or greater in nominal thickness shall not be notched except at the ends of the members. The diameter of holes bored or cut into members shall not exceed one-third the depth of the member. Holes shall not be closer than 2 inches (51 mm) to the top or bottom of the member, or to any other hole located in the member. Where the member is notched, the hole shall not be closer than 2 inches (51 mm) to the notch.
R502.8.2 Engineered wood products. Cuts, notches and holes bored in trusses, structural composite lumber, structural gluedlaminated members, cross-laminated timber members or I-joists are prohibited except where permitted by the manufacturer’s recommendations or where the effects of such alterations are specifically considered in the design of the member by a registered design professional.
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.
CRC § 3.4 High relevance — show source text
Exceptions:
- The top plates are two 2-inch by 6-inch (38 mm by 140 mm) or two 3-inch by 4-inch (64 mm by 89 mm) members.
- A third top plate is installed.
- Solid blocking equal in size to the studs is installed to reinforce the double top plate.
R602.3.4 Bottom (sole) plate. Studs shall have full bearing on a nominal 2-by (51 mm) or larger plate or sill having a width not less than to the width of the studs.
R602.3.4.1 Rodent proofing. Annular spaces around pipes, electric cables, conduits or other openings in bottom/sole plates at exterior walls shall be protected against the passage of rodents by closing such openings in accordance with the California Green Building Standards Code, Chapter 4, Division 4.4.
R602.3.5 Braced wall panel uplift load path. Braced wall panels located at exterior walls that support roof rafters or trusses (including stories below top story) shall have the framing members connected in accordance with one of the following:
- Fastening in accordance with Table R602.3(1) where: 1.1. The ultimate design wind speed does not exceed 115 mph (51 m/s), the wind exposure category is B, the roof pitch is 5:12 or greater, and the roof span is 32 feet (9754 mm) or less.
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1.2. The net uplift value at the top of a wall does not exceed 100 plf (146 N/mm). The net uplift value shall be determined in accordance with Section R802.11 and shall be permitted to be reduced by 60 plf (86 N/mm) for each full wall above.
- Where the net uplift value at the top of a wall exceeds 100 plf (146 N/mm), installing approved uplift framing connectors to provide a continuous load path from the top of the wall to the foundation or to a point where the uplift force is 100 plf (146 N/mm) or less. The net uplift value shall be as determined in Item 1.2.
- Wall sheathing and fasteners designed to resist combined uplift and shear forces in accordance with accepted engineering practice.
R602.4 Interior load-bearing walls. Interior load-bearing walls shall be constructed, framed and fireblocked as specified for exterior walls.
R602.5 Interior nonbearing walls. Interior nonbearing walls shall be permitted to be constructed with 2-inch by 3- inch (51 mm by 76 mm) studs spaced 24 inches (610 mm) on center or, where not part of a braced wall line, 2-inch by 4- inch (51 mm by 102 mm) flat studs spaced at 16 inches (406 mm) on center. Interior nonbearing walls shall be capped with not less than a single top plate. Interior nonbearing walls shall be fireblocked in accordance with Section R602.8.
R602.6 Drilling and notching of studs. Drilling and notching of studs shall be in accordance with the following:
- Notching. A stud in an exterior wall or bearing partition shall not be cut or notched to a depth exceeding 25 percent of its depth. Studs in nonbearing partitions shall not be notched to a depth exceeding 40 percent of a single stud depth.
CRC § 2308.6.1.1 High relevance — show source text
2308.6.1.1 Ceiling joists. Where ceiling joists also serve as floor joists, they shall be considered floor joists within this section.
2308.6.2 Wall studs. In exterior walls and bearing partitions, a wood stud shall not be cut or notched in excess of 25 percent of its depth. In nonbearing partitions that do not support loads other than the weight of the partition, a stud shall not be cut or notched in excess of 40 percent of its depth.
2308.6.3 Bored holes. The diameter of bored holes in wood studs shall not exceed 40 percent of the stud depth. The diameter of bored holes in wood studs shall not exceed 60 percent of the stud depth in nonbearing partitions. The diameter of bored holes in wood studs shall not exceed 60 percent of the stud depth in any wall where each stud is doubled, provided that not more than two such successive doubled studs are so bored. The edge of the bored hole shall not be closer than [5] / 8 inch (15.9 mm) to the edge of the stud. Bored holes shall not be located at the same section of stud as a cut or notch.
2308.6.4 Limitations. In designated lateral force-resisting system assemblies designed in accordance with this code and greater than three stories in height or in Seismic Design Categories C, D, E and F, the cutting, notching and boring of wall studs shall be as prescribed by the registered design professional.
In structures designed in accordance with the California Residential Code, modification of wall studs shall comply with the Cali- fornia Residential Code .
2308.7 Foundations and footings. Foundations and footings shall be designed and constructed in accordance with Chapter 18. Connections to foundations and footings shall comply with this section.
2308.7.1 Foundation plates or sills. Foundation plates or sills resting on concrete or masonry foundations shall comply with Section 2304.3.1. Foundation plates or sills shall be bolted or anchored to the foundation with not less than [1] / 2 -inch-diameter (12.7 mm) steel bolts or approved anchors spaced to provide equivalent anchorage as the steel bolts. Bolts shall be embedded not less than 7 inches (178 mm) into concrete or masonry. The bolts shall be located in the middle third of the width of the plate. Bolts shall be spaced not more than 6 feet (1829 mm) on center and there shall be not less than two bolts or anchor straps per piece with one bolt or anchor strap located not more than 12 inches (305 mm) or less than 4 inches (102 mm) from each end of each piece. Bolts in sill plates of braced wall lines in structures over two stories above grade shall be spaced not more than 4 feet (1219 mm) on center. A properly sized nut and washer shall be tightened on each bolt to the plate.
2308.7.1.1 Braced wall line sill plate anchorage in Seismic Design Category D. Sill plates along braced wall lines in buildings assigned to Seismic Design Category D shall be anchored with not less than [1] / 2 -inch (12.7 mm) diameter anchor bolts with steel plate washers between the foundation sill plate and the nut, or approved anchor straps load-rated in accordance with Section 2304.10.4 and spaced to provide equivalent anchorage.
CRC § 6.1 High relevance — show source text
The sill plate shall provide a minimum nominal bearing area of 48 square inches (30 865 mm [2] ).
R502.6.1 Floor systems. Joists framing from opposite sides over a bearing support shall lap not less than 3 inches (76 mm) and shall be nailed together with a minimum three 10d face nails. A wood or metal splice with strength equal to or greater than that provided by the nailed lap is permitted.
R502.6.2 Joist framing. Joists framing into the side of a wood girder shall be supported by approved framing anchors or on ledger strips not less than nominal 2 inches by 2 inches (51 mm by 51 mm).
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:
- Trusses, structural composite lumber, structural glued-laminated members and I-joists shall be supported laterally as required by the manufacturer’s recommendations.
- In Seismic Design Categories D 0, D 1 and D 2, lateral restraint shall be provided at each intermediate support.
R502.7.1 Bridging. Joists exceeding a nominal 2 inches by 12 inches (51 mm by 305 mm) shall be supported laterally by solid blocking, diagonal bridging (wood or metal), or a continuous 1-inch by 3-inch (25 mm by 76 mm) strip nailed across the bottom of joists perpendicular to joists at intervals not exceeding 8 feet (2438 mm).
Exception: Trusses, structural composite lumber, structural glued-laminated members and I-joists shall be supported laterally as required by the manufacturer’s recommendations.
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
Col1 Col2 Col3 Col4 Col5 Col6 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.
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CRC § 2308.3 High relevance — show source text
2308.3 Portions or elements exceeding limitations of conventional light-frame construction. Where a building of otherwise conventional light-frame construction contains portions or structural elements that exceed the limits of Section 2308.2, those portions or elements, and the supporting load path, shall be designed in accordance with accepted engineering practice and the provisions of this code. For the purposes of this section, the term “portions” shall mean parts of buildings containing volume and area such as a room or a series of rooms. The extent of such design need only demonstrate compliance of the nonconventional lightframed elements with other applicable provisions of this code and shall be compatible with the performance of the conventional light-framed system.
2308.4 Structural elements or systems not described herein. Where a building of otherwise conventional construction contains structural elements or systems not described in Section 2308, these elements or systems shall be designed in accordance with accepted engineering practice and the provisions of this code. The extent of such design need only demonstrate compliance of the nonconventional elements with other applicable provisions of this code and shall be compatible with the performance of the conventionally framed system.
2308.5 Connectors and fasteners. Connectors and fasteners used in conventional construction shall comply with the requirements of Section 2304.10.
2308.6 Cutting, notching and boring of dimensional wood framing. The provisions of this section shall only apply to dimensional wood framing and shall not include engineered wood products, heavy timber or prefabricated/manufactured wood assemblies.
2308.6.1 Floor joists, roof rafters and ceiling joists. Notches on framing ends shall not exceed one-fourth the member depth. Notches in the top or bottom of the member shall not exceed one-sixth the depth and shall not be located in the middle third of the span. A notch not more than one-third of the depth is permitted in the top of a rafter or ceiling joist not further from the face of the support than the depth of the member. Holes bored in members shall not be within 2 inches (51 mm) of the top or bottom of the member and the diameter of any such hole shall not exceed one-third the depth of the member. Where the member is notched, the hole shall not be closer than 2 inches (51 mm) to the notch.
2308.6.1.1 Ceiling joists. Where ceiling joists also serve as floor joists, they shall be considered floor joists within this section.
2308.6.2 Wall studs. In exterior walls and bearing partitions, a wood stud shall not be cut or notched in excess of 25 percent of its depth. In nonbearing partitions that do not support loads other than the weight of the partition, a stud shall not be cut or notched in excess of 40 percent of its depth.
2308.6.3 Bored holes. The diameter of bored holes in wood studs shall not exceed 40 percent of the stud depth. The diameter of bored holes in wood studs shall not exceed 60 percent of the stud depth in nonbearing partitions. The diameter of bored holes in wood studs shall not exceed 60 percent of the stud depth in any wall where each stud is doubled, provided that not more than two such successive doubled studs are so bored. The edge of the bored hole shall not be closer than [5] / 8 inch (15.9 mm) to the edge of the stud. Bored holes shall not be located at the same section of stud as a cut or notch.
CRC § 3.2 High relevance — show source text
6 screws in accordance with Section R702 and structural sheathing installed in accordance with Section R603.9 and Table R603.3.2(1). 2. Horizontal steel straps fastened in accordance with Figure R603.3.3(1) on both sides at mid-height for 8-foot (2438 mm) walls, and at one-third points for 9-foot and 10-foot (2743 mm and 3048 mm) walls. Horizontal steel straps shall be not less than 1 [1] / 2 inches in width and 33 mils in thickness (38 mm by 0.84 mm). Straps shall be attached to the flanges of studs with one No. 8 screw. In-line blocking shall be installed between studs at the termination of straps and at 12-foot (3658 mm) intervals along the strap. Straps shall be fastened to the blocking with two No. 8 screws. 3. Sheathing on one side and strapping on the other side fastened in accordance with Figure R603.3.3(2). Sheathing shall be installed in accordance with Item 1. Steel straps shall be installed in accordance with Item 2.
2025 CALIFORNIA RESIDENTIAL CODE 6-75
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL CONSTRUCTION
FIGURE R603.3.3(1)—STUD BRACING WITH STRAPPING ONLY
TO FORM VERTICAL
1½ ″ x 33 MIL FLAT STRIP (MINIMUM)
WALL FRAMING
@ EACH STRAP TO STUD
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm.
FIGURE R603.3.3(2)—STUD BRACING WITH STRAPPING AND SHEATHING MATERIAL
STUD/TRACK BLOCKING
WALL FRAMING
1½ ″ x 33 MIL FLAT STRAP
BEND SECTION OR CLIP FLANGE TO FORM VERTICAL
2 NO. 8 SCREWS @ STRAP TO BLOCKING
NO. 8 SCREW
@ EACH STRAP TO STUD
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm.
R603.3.4 Cutting and notching. Flanges and lips of cold-formed steel studs and headers shall not be cut or notched.
R603.3.5 Splicing. Steel studs and other structural members shall not be spliced without an approved design. Tracks shall be spliced in accordance with Figure R603.3.5.
6-76 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL CONSTRUCTION
FIGURE R603.3.5—TRACK SPLICE
For SI: 1 inch = 25.4 mm.
R603.4 Corner framing. In exterior walls, corner studs and the top tracks shall be installed in accordance with Figure R603.4.
FIGURE R603.4—CORNER FRAMING
4 NO. 8 SCREWS AT LAPPED TRACK
TRACK
PLAN
ALTERNATE PLAN
For SI: 1 inch = 25.4 mm.
CRC § 3.3 High relevance — show source text
FIGURE R603.3.3(2)—STUD BRACING WITH STRAPPING AND SHEATHING MATERIAL
STUD/TRACK BLOCKING
WALL FRAMING
1½ ″ x 33 MIL FLAT STRAP
BEND SECTION OR CLIP FLANGE TO FORM VERTICAL
2 NO. 8 SCREWS @ STRAP TO BLOCKING
NO. 8 SCREW
@ EACH STRAP TO STUD
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm, 1 foot = 304.8 mm.
R603.3.4 Cutting and notching. Flanges and lips of cold-formed steel studs and headers shall not be cut or notched.
R603.3.5 Splicing. Steel studs and other structural members shall not be spliced without an approved design. Tracks shall be spliced in accordance with Figure R603.3.5.
6-76 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL CONSTRUCTION
FIGURE R603.3.5—TRACK SPLICE
For SI: 1 inch = 25.4 mm.
R603.4 Corner framing. In exterior walls, corner studs and the top tracks shall be installed in accordance with Figure R603.4.
FIGURE R603.4—CORNER FRAMING
4 NO. 8 SCREWS AT LAPPED TRACK
TRACK
PLAN
ALTERNATE PLAN
For SI: 1 inch = 25.4 mm.
R603.5 Exterior wall covering. The method of attachment of exterior wall covering materials to cold-formed steel stud wall framing shall conform to the manufacturer’s installation instructions.
R603.6 Headers. Headers shall be installed above all wall openings in exterior walls and interior load-bearing walls. Box beam headers and back-to-back headers each shall be formed from two equal sized C-shaped members in accordance with Figures R603.6(1) and R603.6(2), respectively, and Tables R603.6(1) through R603.6(6). L-shaped headers shall be permitted to be constructed in accordance with AISI S230. Alternately, headers shall be permitted to be designed and constructed in accordance with AISI S240.
2025 CALIFORNIA RESIDENTIAL CODE 6-77
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL CONSTRUCTION
TABLE R603.6(1)—BOX-BEAM AND BACK-TO-BACK HEADER SPANS
(HEADERS SUPPORTING ROOF AND CEILING ONLY)a, b, dCol2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 MEMBER
DESIGNATIONGROUND SNOW LOAD
(20 psf)GROUND SNOW LOAD
(20 psf)GROUND SNOW LOAD
(20 psf)GROUND SNOW LOAD
(20 psf)GROUND SNOW LOAD
(20 psf)GROUND SNOW LOAD
(30 psf)GROUND SNOW LOAD
(30 psf)GROUND SNOW LOAD
**(30CRC § 0.5 Medium relevance — show source text
B, C, D0, D1, D2|10 <H ≤ 12|H ≤ 8_T_ 0.5
(H ≤ 140_T_ 0.5)|≤ 4 inchese| |Reinforcedd cement, cement-lime,
lime or soil-cement plaster|≤ 140|A, B, C, D0, D1, D2|H ≤ 10|H ≤ 9_T_ 0.5
(H ≤ 157_T_ 0.5)|≤ 6 inches| |Reinforcedd cement, cement-lime,
lime or soil-cement plaster|≤ 155|A, B, C, D0, D1, D2|H ≤ 12|H ≤ 9_T_ 0.5
(H ≤ 157_T_ 0.5)|≤ 4 inchese| |2 × 6 load-bearing wood studsf at
max. 6′ o.c.|≤ 140|A, B, C, D0, D1, D2|H g ≤ 9|NA|None required| |2 × 6 load-bearing wood studsf at
max. 4′ o.c.|≤ 140|A, B, C, D0, D1, D2|H g ≤ 10|NA|None required| |2 × 6 load-bearing wood studsf at
max. 2′ o.c.|≤ 140|A, B, C, D0, D1, D2|H g ≤ 12|NA|None required| |2 × 4 load-bearing wood studsf at
max. 2′ o.c.|≤ 140|A, B, C, D0, D1, D2|H g ≤ 10|NA|None required| |2 × 6 nonload-bearing wood studsf
at max. 6′ o.c.|≤ 140|A, B, C, D0, D1, D2|H g ≤ 12|NA|None required| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.
NA = Not Applicable.
a. Finishes applied to both sides of stacked bales. Where different finishes are used on opposite sides of a wall, the more restrictive requirements shall apply.
b.H = Stacked bale height in feet (mm) between sill plate and top plate or other approved horizontal restraint, or the horizontal distance in feet (mm) between approved verti-
cal restraints. For load-bearing walls,H refers to vertical height only.
c.T = Bale thickness in feet (mm).
d. Plaster reinforcement shall be any mesh allowed in Table BJ106.13(1) for the matching plaster type, and with staple spacing in accordance with this table. Mesh shall be
installed in accordance with Section BJ106.9.
e. Sill plate attachment shall be with5/8-inch anchor bolts or approved equivalent at not more than 48 inches on center where staple spacing is required to be ≤ 4 inches.
f. Bales shall be attached to the studs by an approved method. Horizontal framing and attachment at top and bottom of studs shall be in accordance with Section R602 or an
approved alternative.CRC § 2.5 Medium relevance — show source text
Wall studs not exceeding 16 inches on center shall be sheathed with minimum1/2-inch gypsum board on the interior and3/8-inch wood structural panel sheathing on the exte-
rior. Wood structural panel sheathing shall be attached with 8d (2.5″ × 0.131″) nails not greater than 6 inches on center along panel edges and 12 inches on center at
intermediate supports, and all panel joints shall occur over studs or blocking.
b. Where the ultimate design wind speed exceeds 115 mph, studs shall be attached to top and bottom plates with connectors having a minimum 300-pound lateral capacity.
c. The maximum span is applicable to both single- and multiple-span roof and floor conditions. The roof assembly shall not contain a habitable attic.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mph = 0.447 m/s, 1 pound = 4.448 N.
DR = Design Required.
a. Wall studs not exceeding 16 inches on center shall be sheathed with minimum1/2-inch gypsum board on the interior and3/8-inch wood structural panel sheathing on the exte-
rior. Wood structural panel sheathing shall be attached with 8d (2.5″ × 0.131″) nails not greater than 6 inches on center along panel edges and 12 inches on center at
intermediate supports, and all panel joints shall occur over studs or blocking.
b. Where the ultimate design wind speed exceeds 115 mph, studs shall be attached to top and bottom plates with connectors having a minimum 300-pound lateral capacity.
c. The maximum span is applicable to both single- and multiple-span roof and floor conditions. The roof assembly shall not contain a habitable attic.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mph = 0.447 m/s, 1 pound = 4.448 N.
DR = Design Required.
a. Wall studs not exceeding 16 inches on center shall be sheathed with minimum1/2-inch gypsum board on the interior and3/8-inch wood structural panel sheathing on the exte-
rior. Wood structural panel sheathing shall be attached with 8d (2.5″ × 0.131″) nails not greater than 6 inches on center along panel edges and 12 inches on center at
intermediate supports, and all panel joints shall occur over studs or blocking.
b. Where the ultimate design wind speed exceeds 115 mph, studs shall be attached to top and bottom plates with connectors having a minimum 300-pound lateral capacity.
c. The maximum span is applicable to both single- and multiple-span roof and floor conditions. The roof assembly shall not contain a habitable attic.|6-10 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL CONSTRUCTION
SEE DRILLING AND
NOTCHING PROVISIONS
SECTION R602.6.1
SEE DRILLING AND
NOTCHING PROVISIONS
SECTION R602.6
JOIST NAILED TO
1 IN. x 4 IN. RIBBON
CUT INTO STUD—
SEE SECTION R502.6
SEE SECTION R602.8
FOR FIREBLOCKING
FIGURE R602.3(1)—TYPICAL WALL, FLOOR AND ROOF FRAMING
Frequently asked questions
Can I drill a 2-inch hole in a 2x6 exterior stud?
Yes — a 2×6 has an actual depth of about 5.5 inches (this actual depth is not specified in § R602.6). For exterior/bearing studs the normal un-doubled limit is 40% of stud depth (≈ 2.2 in for a 5.5 in stud). A 2 in hole would be under 40% and is permitted provided the hole edge is ≥ 5/8 in from the stud edge and not in the same cross section as a notch. § R602.6.
What does “doubled stud” mean here?
A doubled stud is two studs installed side-by-side (or equivalent framing such that the stud is backed up) so the drilled hole is in a doubled member; the code requires doubling when a bored hole in an exterior/bearing stud exceeds 40% of stud depth. § R602.6.
Are holes and notches allowed in the same location?
No. The code explicitly prohibits placing a bored hole in the same cross section of a stud as a cut or notch. § R602.6.
What if I must cut more than 50% of the top plate width for piping?
If a top plate (exterior or interior load-bearing wall) is cut/drilled/notched by more than 50%, you must install a galvanized metal tie (min 0.054 in / 16 ga, 1.5 in wide) fastened with 8–10d nails at each side and extending 6 in past the opening — unless the entire side of the wall is covered by wood structural panel sheathing (exception). § R602.6.1.
Can the code be overridden by the manufacturer's instructions or an engineer?
Yes — for engineered wood products follow the manufacturer’s instructions, and where a registered design professional (engineer/architect) designs the modifications, that design controls. Also approved alternatives such as stud shoes are permitted if installed per manufacturer instructions. § R502.8.2, § R602.6.
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