CRC · California Residential Code

When is a single top plate permitted and how must top plates be spliced?

Q: What splice plate and nail count do I need for a butt joint in SDC C?

Use a 3″ × 12″ × 0.036″ galvanized splice plate with 12 × 8d box nails each side per Table R602.3.2 .

Q: Are there special rules for notching top plates for pipes?

Yes. If piping/ductwork cuts more than 50% of a top plate width, a galvanized metal tie (16 gage, 1½″ wide) with specified nailing is required per § R602.6.1 .

A single top plate is only allowed as an exception in the California Residential Code when the wall is tied at corners, intersections and splices using the exact splice-plate sizes and nail counts shown in Table R602.3.2, the rafters/joists are centered over studs within 1 inch, and headers omitted over openings are tied as the table requires.

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Last reviewed: July 6, 2026

What the code requires — plain English

A wood stud wall normally requires a double top plate. The CRC allows a single top plate only as an exception when it is tied at corners, intersecting walls and in-line splices per the splice details in § R602.3.2 and Table R602.3.2. The rafters/joists must be centered over the studs within 1 inch, and headers may be omitted only when they are tied to adjacent wall sections in accordance with Table R602.3.2.

The single most important rule: a single top plate is allowed only when you provide the specified splice/tie hardware and nailing required by § R602.3.2 and Table R602.3.2.

Requirements in detail

Basic rule and plate dimensions

Walls must be capped with a double top plate, except as provided in the exception at § R602.3.2 for a single top plate. Plates shall be nominally 2 inches thick and have a width not less than the studs. § R602.3.2.

When a single top plate is allowed (key conditions)

The single top plate must be tied at corners, intersecting walls, and at in-line splices in straight wall lines in accordance with Table R602.3.2. § R602.3.2.
Rafters or joists must be centered over studs within ±1 inch. § R602.3.2.
The top plate may be omitted over headers only when those headers are tied to adjacent wall sections as required by Table R602.3.2. § R602.3.2.

Splice / tie hardware and nailing — decision table

Use the splice sizes and minimum nails specified in Table R602.3.2. The table varies by Seismic Design Category (SDC) and braced wall line spacing.

Condition	Splice location	Splice plate size (min)	Minimum nails each side of joint	Code reference
Structures in SDC A–C; and in SDC D0, D1, D2 with braced wall line spacing < 25 ft	Corners & intersecting walls	3″ × 6″ × 0.036″ galvanized (or equivalent)	6 × 8d box nails each side	Table R602.3.2, § R602.3.2
Same condition	Butt joints in straight walls	3″ × 12″ × 0.036″ galvanized (or equivalent)	12 × 8d box nails each side	Table R602.3.2, § R602.3.2
Structures in SDC D0, D1, D2 with braced wall line spacing ≥ 25 ft	Corners & intersecting walls	3″ × 8″ × 0.036″ galvanized (or equivalent)	9 × 8d box nails each side	Table R602.3.2, § R602.3.2
Same condition	Butt joints in straight walls	3″ × 16″ × 0.036″ galvanized (or equivalent)	18 × 8d box nails each side	Table R602.3.2, § R602.3.2

Notes:

Nail size referenced in the table is 8d box (2½″ × 0.113″) (see Table R602.3.2). See the table text for equivalent fastener types allowed.
“Butt joint” means the end-to-end splice in a straight run of top plate; corners/intersections are the splice plates used where walls intersect or change direction. Table R602.3.2.

Other plate splice and edge rules

End joints in top plates are required to be offset (CRC requires plate end joints offset; CRC uses 24 inches for top plate end joint offset) — see § R602.3.2.
When piping/ducting notches exceed 50% of the top plate width, special metal ties and nailing are required (see § R602.6.1).

Exceptions & special cases

Where the building has two 2×6 top plates or two 3×4 top plates, or where a third top plate is installed, the single-plate splice requirements do not apply (these are exceptions listed adjacent to § R602.3.2).
In high-seismic areas (SDC D0/D1/D2) with braced wall lines ≥ 25 ft, the table requires larger splice plates and more nails—plan accordingly. Table R602.3.2.
The CRC permits omission of the top plate over headers only when those headers are tied to adjacent wall sections per Table R602.3.2. § R602.3.2.
Where bearing stud spacing and supported member spacing interact (bearing studs at 24 in o.c. and roof/floor members spaced >16 in o.c.), the code addresses bearing location or need for a third plate (see related provisions). The specific bearing/stud rule is in § R602.3.3.

If a required condition or dimension is not present in the retrieved CRC text, it is noted in the related-provisions list below rather than invented.

Common mistakes

Assuming a single top plate is allowed anywhere without ties — it is permitted only under the § R602.3.2 exception and only when tied per Table R602.3.2.
Using a smaller splice plate or fewer nails than Table R602.3.2 specifies — the table’s plate sizes and nail counts are the minimum.
Forgetting to center rafters/joists within 1 inch over studs; single-plate allowance requires this. § R602.3.2.
Leaving top plate out above a header without providing the specified ties; omission is allowed only when tied per the Table. § R602.3.2.
Confusing the CRC offset requirement for top plate end joints with other codes; in the CRC end joints in top plates must be offset per § R602.3.2.

Worked example

Scenario: Single-story dwelling in SDC C, straight wall run with a butt joint (in-line splice) and rafters centered over studs.

Determine applicable row: SDC C => use the SDC A–C row in Table R602.3.2.
For a butt joint in a straight wall, Table R602.3.2 requires a 3″ × 12″ × 0.036″ galvanized splice plate nailed with 12 × 8d box nails to each side of the joint. So install the 3×12 plate centered over the butt joint and drive 12 nails into the plate on the wall side and 12 on the other wall side (total 24 nails). Table R602.3.2, § R602.3.2.
Verify rafters/joists are centered over the studs within 1 inch — if not, do not use the single-plate exception. § R602.3.2.
If this wall were in SDC D1 and the braced wall lines were ≥25 ft apart, you would use the larger 3″ × 16″ splice plate and 18 nails each side instead. Table R602.3.2.

Related provisions (CRC)

§ R602.3.1 — Stud size, height and spacing (top-plate context)
§ R602.3.3 — Bearing studs and bearing location requirements (bearing studs at 24 in o.c. interaction)
§ R602.6.1 — Drilling/notching of top plates and required metal ties when >50% of plate width is cut/notched
§ R602.5 — Interior nonbearing walls may be capped with a single top plate (context and spacing rules)
§ R602.10.8.1 — Braced wall panel top-plate lap nailing requirements for SDC D0/D1/D2 (uplift/connection context)

If you want, I can extract the exact wording of Table R602.3.2 into a construction-ready checklist or produce a simple field sketch showing plate placement and nail patterns to show compliance at corners vs. butt joints.

Code references

Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:

CRC § 2308.9.3.2 High relevance — show source text
Plates or sills shall be not less than 2 inches (51 mm) nominal in thickness and have a width not less than the width of the wall studs.

2308.9.3.2 Top plates. Bearing and exterior wall studs shall be capped with double top plates installed to provide overlapping at corners and at intersections with other partitions. End joints in double top plates shall be offset not less than 48 inches (1219 mm), and shall be nailed in accordance with Table 2304.10.2. Plates shall be a nominal 2 inches (51 mm) in depth and have a width not less than the width of the studs.

Exception: A single top plate is permitted, provided that the plate is adequately tied at corners and intersecting walls by not less than the equivalent of 3-inch by 6-inch (76 mm by 152 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by six 8d [2 [1] / 2 -inch by 0.113-inch (64-mm by 2.87 mm)] box nails or equivalent on each side of the joint. For the butt-joint splice between adjacent single top plates, not less than the equivalent of a 3-inch by 12inch (76 mm by 304 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by 12 8d [2 [1] / 2 -inch by 0.113-inch (64 mm by 2.87 mm)] box nails on each side of the joint shall be required, provided that the rafters, joists or trusses are centered over the studs with a tolerance of not more than 1 inch (25 mm). The top plate shall not be required over headers that are in the same plane and in line with the upper surface of the adjacent top plates and are tied to adjacent wall sections as required for the butt joint splice between adjacent single top plates. Where bearing studs are spaced at 24-inch (610 mm) intervals, top plates are less than two 2-inch by 6-inch (51 mm by 152 mm) or two 3-inch by 4-inch (76 mm by 102 mm) members and the floor joists, floor trusses or roof trusses that they support are spaced at more than 16-inch (406 mm) intervals, such joists or trusses shall bear within 5 inches (127 mm) of the studs beneath or a third plate shall be installed. 2308.9.4 Nonload-bearing walls and partitions. In nonload-bearing walls and partitions, that are not part of a braced wall panel, studs shall be spaced not more than 24 inches (610 mm) on center. In interior nonload-bearing walls and partitions, studs are permitted to be set with the long dimension parallel to the wall. Where studs are set with the long dimensions parallel to the wall, use of utility grade lumber or studs exceeding 10 feet (3048 mm) is not permitted. Interior nonload-bearing partitions shall be capped with not less than a single top plate installed to provide overlapping at corners and at intersections with other walls and partitions. The plate shall be continuously tied at joints by solid blocking not less than 16 inches (406 mm) in length and equal in size to the plate or by [1] / 2 -inch by 1 [1] / 2 -inch (12.7 mm by 38 mm) metal ties with spliced sections fastened with two 16d nails on each side of the joint.

CRC § 3.2. High relevance — show source text

Exception: A single top plate used as an alternative to a double top plate shall comply with the following:

The single top plate shall be tied at corners, intersecting walls, and at in-line splices in straight wall lines in accordance with Table R602.3.2.
The rafters or joists shall be centered over the studs with a tolerance of not more than 1 inch (25 mm).
Omission of the top plate is permitted over headers where the headers are adequately tied to adjacent wall sections in accordance with Table R602.3.2.

TABLE R602.3.2—SINGLE TOP-PLATE SPLICE CONNECTION DETAILS	Col2	Col3	Col4	Col5
CONDITION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION
CONDITION	Corners and intersecting walls	Corners and intersecting walls	Butt joints in straight walls	Butt joints in straight walls
CONDITION	Splice plate size	Minimum nails each side of joint	Splice plate size	Minimum nails each side of joint
Structures in SDC A-C; and in SDC D0, D1 and D2 with braced wall line spacing less than 25 feet	3″ × 6″ × 0.036″ galvanized steel plate or equivalent	(6) 8d box (21/2″ × 0.113″) nails	3″× 12″ × 0.036″ galvanized steel plate or equivalent	(12) 8d box (21/2″ × 0.113″) nails
Structures in SDC D0, D1 and D2, with braced wall line spacing greater than or equal to 25 feet	3″ × 8″ × 0.036″ galvanized steel plate or equivalent	(9) 8d box (21/2″ × 0.113″) nails	3″ × 16″ × 0.036″ galvanized steel plate or equivalent	(18) 8d box (21/2″ × 0.113″) nails
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.	For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.	For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.	For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.	For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

R602.3.3 Bearing studs. Where joists, trusses or rafters are spaced more than 16 inches (406 mm) on center and the bearing studs below are spaced 24 inches (610 mm) on center, such members shall bear within 5 inches (127 mm) of the studs beneath.

CRC § 23-43 High relevance — show source text
Increases in unsupported height are permitted where justified by
an analysis.
b. Shall not be used in exterior walls.
c. Utility-grade studs shall not be spaced more than 16 inches on center or support more than a roof and ceiling, or exceed 8 feet in height for exterior walls and load-bearing
walls or 10 feet for interior nonload-bearing walls.|

2025 CALIFORNIA BUILDING CODE 23-43

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WOOD

2308.9.2 Framing details. Studs shall be placed with their wide dimension perpendicular to the wall. Not less than three studs shall be installed at each corner of an exterior wall.

Exceptions:
1. In interior nonbearing walls and partitions, studs are permitted to be set with the long dimension parallel to the wall.
2. At corners, two studs are permitted, provided that wood spacers or backup cleats of [3] / 8 -inch-thick (9.5 mm) wood structural panel, [3] / 8 -inch (9.5 mm) Type M “Exterior Glue” particleboard, 1-inch-thick (25 mm) lumber or other approved devices that will serve as an adequate backing for the attachment of facing materials are used. Where fireresistance ratings or shear values are involved, wood spacers, backup cleats or other devices shall not be used unless specifically approved for such use. 2308.9.3 Plates and sills. Studs shall have plates and sills in accordance with this section. 2308.9.3.1 Bottom plate or sill. Studs shall have full bearing on a plate or sill. Plates or sills shall be not less than 2 inches (51 mm) nominal in thickness and have a width not less than the width of the wall studs.
2308.9.3.2 Top plates. Bearing and exterior wall studs shall be capped with double top plates installed to provide overlapping at corners and at intersections with other partitions. End joints in double top plates shall be offset not less than 48 inches (1219 mm), and shall be nailed in accordance with Table 2304.10.2. Plates shall be a nominal 2 inches (51 mm) in depth and have a width not less than the width of the studs.

Exception: A single top plate is permitted, provided that the plate is adequately tied at corners and intersecting walls by not less than the equivalent of 3-inch by 6-inch (76 mm by 152 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by six 8d [2 [1] / 2 -inch by 0.113-inch (64-mm by 2.87 mm)] box nails or equivalent on each side of the joint. For the butt-joint splice between adjacent single top plates, not less than the equivalent of a 3-inch by 12inch (76 mm by 304 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by 12 8d [2 [1] / 2 -inch by 0.113-inch (64 mm by 2.87 mm)] box nails on each side of the joint shall be required, provided that the rafters, joists or trusses are centered over the studs with a tolerance of not more than 1 inch (25 mm).
CRC § 2308.9.4 High relevance — show source text
The top plate shall not be required over headers that are in the same plane and in line with the upper surface of the adjacent top plates and are tied to adjacent wall sections as required for the butt joint splice between adjacent single top plates. Where bearing studs are spaced at 24-inch (610 mm) intervals, top plates are less than two 2-inch by 6-inch (51 mm by 152 mm) or two 3-inch by 4-inch (76 mm by 102 mm) members and the floor joists, floor trusses or roof trusses that they support are spaced at more than 16-inch (406 mm) intervals, such joists or trusses shall bear within 5 inches (127 mm) of the studs beneath or a third plate shall be installed. 2308.9.4 Nonload-bearing walls and partitions. In nonload-bearing walls and partitions, that are not part of a braced wall panel, studs shall be spaced not more than 24 inches (610 mm) on center. In interior nonload-bearing walls and partitions, studs are permitted to be set with the long dimension parallel to the wall. Where studs are set with the long dimensions parallel to the wall, use of utility grade lumber or studs exceeding 10 feet (3048 mm) is not permitted. Interior nonload-bearing partitions shall be capped with not less than a single top plate installed to provide overlapping at corners and at intersections with other walls and partitions. The plate shall be continuously tied at joints by solid blocking not less than 16 inches (406 mm) in length and equal in size to the plate or by [1] / 2 -inch by 1 [1] / 2 -inch (12.7 mm by 38 mm) metal ties with spliced sections fastened with two 16d nails on each side of the joint. 2308.9.5 Openings in walls and partitions. Openings in exterior and interior walls and partitions shall comply with Sections 2308.9.5.1 through 2308.9.5.3. 2308.9.5.1 Openings in exterior bearing walls. Headers shall be provided over each opening in exterior bearing walls. The size and spans in Table 2308.8.1.1(1) are permitted to be used for one- and two-family dwellings . Headers for other buildings shall be designed in accordance with Section 2302.1, Item 1 or 2. Headers of two or more pieces of nominal 2-inch (51 mm) framing lumber set on edge shall be permitted in accordance with Table 2308.8.1.1(1) and nailed together in accordance with Table 2304.10.2 or of solid lumber of equivalent size. Single-member headers of nominal 2-inch (51 mm) thickness shall be framed with a single flat 2-inch-nominal (51 mm) member or wall plate not less in width than the wall studs on the top and bottom of the header in accordance with Figures 2308.9.5.1(1) and 2308.9.5.1(2) and face nailed to the top and bottom of the header with 10d box nails [3 inches × 0.128 inches (76 mm × 3.3 mm)] spaced 12 inches (305 mm) on center. Wall studs shall support the ends of the header in accordance with Table 2308.8.1.1(1). Each end of a lintel or header shall have a bearing length of not less than 1 [1] / 2 inches (38 mm) for the full width of the lintel.
CRC § 3.4 High relevance — show source text
Exceptions:
1. 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.
2. A third top plate is installed.
3. 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:
1. 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.
2025 CALIFORNIA RESIDENTIAL CODE 6-13

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WALL CONSTRUCTION

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.
1. 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.
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:
1. 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 § 25.4 High relevance — show source text
EACH SIDE

For SI: 1 inch = 25.4 mm.

Note: Figure illustrates SIP-specific attachment requirements. Other connections shall be made in accordance with Tables R602.3(1) and R602.3(2), as appropriate.

2025 CALIFORNIA RESIDENTIAL CODE 6-179

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WALL CONSTRUCTION

FIGURE R610.5(5)—SIP WALL-TO-WALL HANGING FLOOR FRAME CONNECTION (I-Joist floor shown for Illustration only)

CONTINUOUS SEALANT

EACH SIDE

2x SOLE PLATE

8d COMMON NAILS AT 6

IN. O.C. EACH SIDE

TOP PLATE

8d COMMON NAILS AT 6

IN. O.C. EACH SIDE

CONTINUOUS SEALANT

EACH SIDE

SIP WALL

FRAMING IN ACCORDANCE

For SI:1 inch = 25.4 mm.

Note: Figure illustrates SIP-specific attachment requirements. Other connections shall be made in accordance with Tables R602.3(1) and R602.3(2), as appropriate. R610.5.1 Top plate connection. SIP walls shall be capped with a double top plate installed to provide overlapping at corner, intersections and splines in accordance with Figure R610.5.1. The double top plates shall be made up of a single 2-by (nominal 2inch) top plate having a width equal to the width of the panel ~~core, an~~ d shall be recessed into the SIP below. Over this top plate a cap plate shall be placed. The cap plate width shall match the SIP thickness and overlap the facers on both sides of the panel. End

The Col2

~~cor~~
SIP e

joints in top plates shall be offset not less than 24 inches (610 mm).

FIGURE R610.5.1—SIP WALL FRAMING CONFIGURATION

2x TOP PLATE

RECESSED INTO SIP CORE, WIDTH EQUAL TO SIP

CORE WIDTH

2x KING STUDS

RECESSED INTO THE SIP CORE, WIDTH EQUAL TO SIP CORE

For SI: 1 inch = 25.4 mm.

Notes:
1. Top plates shall be continuous over header.
2. Lower 2x top plate shall have a width equal to the SIP core width and shall be recessed into the top edge of the panel. Cap plate shall be placed over the recessed top plate and shall have a width equal to the SIP’s width.
3. SIP facing surfaces shall be nailed to framing and cripples with 8d common or galvanized box nails spaced 6 inches on center.
6-180 2025 CALIFORNIA RESIDENTIAL CODE

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WALL CONSTRUCTION

R610.5.2 Bottom (sole) plate connection. SIP walls shall have full bearing on a sole plate having a width equal to the nominal width of the foam core. Where SIP walls are supported directly on continuous foundations, the wall wood sill plate shall be anchored to the foundation in accordance with Figure R610.5.2 and Section R403.1.

FIGURE R610.5.2—SIP WALL TO CONCRETE SLAB FOR FOUNDATION WALL ATTACHMENT

SIP WALL

CONTINUOUS

SEALANT EACH
CRC § 25.4 High relevance — show source text
For SI: 1 inch = 25.4 mm.

6-46 2025 CALIFORNIA RESIDENTIAL CODE

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WALL CONSTRUCTION

R602.10.8.1 Braced wall panel connections for Seismic Design Categories D 0 , D 1 and D 2 . Braced wall panels shall be fastened to required foundations in accordance with Section R602.11.1, and top plate lap splices shall be face-nailed with not less than eight 16d nails on each side of the splice.

R602.10.8.2 Connections to roof framing. Top plates of exterior braced wall panels shall be attached to rafters or roof trusses above in accordance with Table R602.3(1) and this section. Where required by this section, blocking between rafters or roof trusses shall be attached to top plates of braced wall panels and to rafters and roof trusses in accordance with Table R602.3(1). A continuous band, rim or header joist or roof truss parallel to the braced wall panels shall be permitted to replace the blocking required by this section. Blocking shall not be required over openings in continuously sheathed braced wall lines. In addition to the requirements of this section, lateral support shall be provided for rafters and ceiling joists in accordance with Section R802.8 and for trusses in accordance with Section R802.10.3. Roof ventilation shall be provided in accordance with Section R806.1.
1. For Seismic Design Categories A, B and C where the distance from the top of the braced wall panel to the top of the rafters or roof trusses above is 9 [1] / 4 inches (235 mm) or less, blocking between rafters or roof trusses shall not be required. Where the distance from the top of the braced wall panel to the top of the rafters or roof trusses above is between 9 [1] / 4 inches (235 mm) and 15 [1] / 4 inches (387 mm), blocking between rafters or roof trusses shall be provided above the braced wall panel in accordance with Figure R602.10.8.2(1).
Exception: Where the outside edge of truss vertical web members aligns with the outside face of the wall studs below, wood structural panel sheathing extending above the top plate as shown in Figure R602.10.8.2(3) shall be permitted to be fastened to each truss web with three-8d nails (2 [1] / 2 inches × 0.131 inch) and blocking between the trusses shall not be required. 2. For Seismic Design Categories D 0, D 1 and D 2, where the distance from the top of the braced wall panel to the top of the rafters or roof trusses is 15 [1] / 4 inches (387 mm) or less, blocking between rafters or roof trusses shall be provided above the braced wall panel in accordance with Figure R602.10.8.2(1). 3. Where the distance from the top of the braced wall panel to the top of rafters or roof trusses exceeds 15 [1] / 4 inches (387 mm), the top plates of the braced wall panel shall be connected to perpendicular rafters or roof trusses above in accordance with one or more of the following methods: 3.1.

The	Col2

~~cor~~ SIP	e

CRC § 3.1 High relevance — show source text

WALL CONSTRUCTION

R602.3.1 Stud size, height and spacing. The size, height and spacing of studs shall be in accordance with Table R602.3(5).

Exceptions:

Utility grade studs shall not be spaced more than 16 inches (406 mm) on center, shall not support more than a roof and ceiling, and shall not exceed 8 feet (2438 mm) in height for exterior walls and load-bearing walls or 10 feet (3048 mm) for interior nonload-bearing walls.
Where ground snow loads are less than or equal to 25 pounds per square foot (1.2 kPa), and the ultimate design wind speed is less than or equal to 130 mph (58.1 m/s), 2-inch by 6-inch (38 mm by 140 mm) studs supporting a roof load with not more than 6 feet (1829 mm) of tributary length shall have a maximum height of 18 feet (5486 mm) where spaced at 16 inches (406 mm) on center, or 20 feet (6096 mm) where spaced at 12 inches (305 mm) on center. Studs shall be No. 2 grade lumber or better.
Exterior load-bearing studs not exceeding 12 feet (3658 mm) in height provided in accordance with Table R602.3(6). The minimum number of full-height studs adjacent to openings shall be in accordance with Section R602.7.5. The building shall be located in Exposure B, the roof live load shall not exceed 20 psf (0.96 kPa), and the ground snow load shall not exceed 30 psf (1.4 kPa). Studs and plates shall be No. 2 grade lumber or better.

R602.3.2 Top plate. Wood stud walls shall be capped with a double top plate installed to provide overlapping at corners and intersections with bearing partitions. End joints in top plates shall be offset not less than 24 inches (610 mm). Joints in plates need not occur over studs. Plates shall be not less than 2-inches (51 mm) nominal thickness and have a width not less than the width of the studs.

Exception: A single top plate used as an alternative to a double top plate shall comply with the following:

The single top plate shall be tied at corners, intersecting walls, and at in-line splices in straight wall lines in accordance with Table R602.3.2.
The rafters or joists shall be centered over the studs with a tolerance of not more than 1 inch (25 mm).
Omission of the top plate is permitted over headers where the headers are adequately tied to adjacent wall sections in accordance with Table R602.3.2.

TABLE R602.3.2—SINGLE TOP-PLATE SPLICE CONNECTION DETAILS	Col2	Col3	Col4	Col5
CONDITION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION
CONDITION	Corners and intersecting walls	Corners and intersecting walls	Butt joints in straight walls	Butt joints in straight walls
CONDITION	Splice plate size	Minimum nails each side of joint	Splice plate size	Minimum nails each side of joint
Structures in SDC A-C;

CRC § 6-178 High relevance — show source text
Note: Figure illustrates SIP-specific attachment requirements. Other connections shall be made in accordance with Tables R602.3(1) and R602.3(2), as appropriate.

6-178 2025 CALIFORNIA RESIDENTIAL CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

FIGURE R610.5(3)—TRUSSED ROOF TO TOP PLATE CONNECTION

WALL CONSTRUCTION

CAP/TOP PLATE

CONNECTION 16d

COMMON NAILS AT

16 IN. O.C.

CAP PLATE

TOP PLATE

CONTINUOUS SEALANT

EACH SIDE OF FRAMING

AS RECOMMENDED BY

MANUFACTURER

SIP WALL PANEL

For SI: 1 inch = 25.4 mm.

Note: Figure illustrates SIP-specific attachment requirements. Other conn ~~ections shall be made in acc~~ ordance with Tables R602.3(1) and R602.3(2), as appropriate.

FIGURE R610.5(4)—SIP WALL-TO-WALL PLATFORM FRAME CONNECTION

SIP WALL

CONTINUOUS SEALANT

EACH SIDE

ctions shal
ALL-TO- l b e made in ac
ALL PLATF

~~ctions shal~~
ALL-TO- W W

2x SOLE PLATE

MATCHING THE SIP

CORE THICKNESS

8d COMMON NAILS AT 6

IN. O.C. EACH SIDE

RIM BOARD

CAP PLATE

8d NAILS AT 6 IN.

O.C. EACH SIDE

CONTINUOUS SEALANT

EACH SIDE

For SI: 1 inch = 25.4 mm.

Note: Figure illustrates SIP-specific attachment requirements. Other connections shall be made in accordance with Tables R602.3(1) and R602.3(2), as appropriate.

2025 CALIFORNIA RESIDENTIAL CODE 6-179

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

WALL CONSTRUCTION

FIGURE R610.5(5)—SIP WALL-TO-WALL HANGING FLOOR FRAME CONNECTION (I-Joist floor shown for Illustration only)

CONTINUOUS SEALANT

EACH SIDE

2x SOLE PLATE

8d COMMON NAILS AT 6

IN. O.C. EACH SIDE

TOP PLATE

8d COMMON NAILS AT 6

IN. O.C. EACH SIDE

CONTINUOUS SEALANT

EACH SIDE

SIP WALL

FRAMING IN ACCORDANCE

For SI:1 inch = 25.4 mm.

Note: Figure illustrates SIP-specific attachment requirements. Other connections shall be made in accordance with Tables R602.3(1) and R602.3(2), as appropriate. R610.5.1 Top plate connection. SIP walls shall be capped with a double top plate installed to provide overlapping at corner, intersections and splines in accordance with Figure R610.5.1. The double top plates shall be made up of a single 2-by (nominal 2inch) top plate having a width equal to the width of the panel ~~core, an~~ d shall be recessed into the SIP below. Over this top plate a cap plate shall be placed. The cap plate width shall match the SIP thickness and overlap the facers on both sides of the panel. End
CRC § 15-1.12 High relevance — show source text
Exterior or
interior walls—
continued|15-1.12q|2" × 6" wood studs at 16" with double top plates, single
bottom plate; interior and exterior sides covered with5/8" Type
X gypsum wallboard, 4′ wide, applied horizontally or vertically
with vertical joints over studs, and fastened with 21/4" Type S
drywall screws, spaced 12" on center. Cavity to be filled with
51/2" mineral wool insulation.|—|—|—|63/4| |15. Exterior or
interior walls—
continued|15-1.13q|2" × 6" wood studs at 16" with double top plates, single
bottom plate; interior and exterior sides covered with5/8" Type
X gypsum wallboard, 4′ wide, applied vertically with all joints
over framing or blocking and fastened with 21/4" Type S
drywall screws, spaced 12" on center. R-19 mineral fiber insu-
lation installed in stud cavity.|—|—|—|63/4| |15. Exterior or
interior walls—
continued|15-1.14q|2" × 6" wood studs at 16" with double top plates, single
bottom plate; interior and exterior sides covered with5/8" Type
X gypsum wallboard, 4′ wide, applied horizontally or vertically
with vertical joints over studs, and fastened with 21/4" Type S
drywall screws, spaced 7" on center.|—|—|—|63/4| |15. Exterior or
interior walls—
continued|15-1.15q|2" × 4" wood studs at 16" with double top plates, single
bottom plate; interior and exterior sides covered with5/8" Type
X gypsum wallboard and sheathing, respectively, 4′ wide,
applied horizontally or vertically with vertical joints over
studs, and fastened with 21/4" Type S drywall screws, spaced
12" on center. Cavity to be filled with 31/2" mineral wool
insulation.|—|—|—|43/4| |15. Exterior or
interior walls—
continued|15-1.16q|2" × 6" wood studs at 24" centers with double top plates,
single bottom plate; interior and exterior side covered with
two layers of5/8" Type X gypsum wallboard, 4′ wide, applied
horizontally with vertical joints over studs. Base layer fastened
with 21/4" Type S drywall screws, spaced 24" on center and
face layer fastened with Type S drywall screws, spaced 8" on
center, wallboard joints covered with paper tape and joint
compound, fastener heads covered with joint compound.
Cavity to be filled with 51/2" mineral wool insulation.|—|—|8|—|

2025 CALIFORNIA BUILDING CODE 7-53

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

FIRE AND SMOKE PROTECTION FEATURES
CRC § 1.2. High relevance — show source text
1. 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.
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:
1. 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.
2. 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.

6-14 2025 CALIFORNIA RESIDENTIAL CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

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

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

WALL CONSTRUCTION
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

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

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

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

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

ctions shal ALL-TO-	l b	e made in ac ALL PLATF
~~ctions shal~~ ALL-TO-	W	W

Frequently asked questions

Can I always substitute a single top plate for a double top plate if I add a splice plate?

No. The single top plate is permitted only as the exception in § R602.3.2 and only when all conditions are met (ties per Table R602.3.2, rafters/joists centered within 1 inch, and header-tie conditions if omitting over headers).

What splice plate and nail count do I need for a butt joint in SDC C?

Use a 3″ × 12″ × 0.036″ galvanized splice plate with 12 × 8d box nails each side per Table R602.3.2.

If my house is in SDC D1 and braced wall lines are 30 ft apart, what changes?

You must use the larger splice plates and greater nail quantities shown in the SDC D0/D1/D2 with braced wall line spacing ≥ 25 ft rows of Table R602.3.2 (e.g., 3″×16″ plate and 18 nails each side for butt joints).

Are there special rules for notching top plates for pipes?

Yes. If piping/ductwork cuts more than 50% of a top plate width, a galvanized metal tie (16 gage, 1½″ wide) with specified nailing is required per § R602.6.1.

Do end joints in top plates have to be offset?

Yes—end joints in top plates must be offset as required by the CRC top-plate provisions in § R602.3.2.

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Related in the CRC

How must bearing studs and braced wall uplift load paths be handled?

What are the prescriptive stud sizes, heights and spacing limits?

Wood framing — studs, plates, bearing and uplift

California Residential Code

TABLE R602.3.2—SINGLE TOP-PLATE SPLICE CONNECTION DETAILS	Col2	Col3	Col4	Col5
CONDITION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION	TOP-PLATE SPLICE LOCATION
CONDITION	Corners and intersecting walls	Corners and intersecting walls	Butt joints in straight walls	Butt joints in straight walls
CONDITION	Splice plate size	Minimum nails each side of joint	Splice plate size	Minimum nails each side of joint
Structures in SDC A-C;