- Lumber
- Nails
- Framing Connectors
- Subflooring
- Dimensional Lumber Floors
- Engineered Lumber Floors
- Floor Trusses
- Wall Framing
- Sheathing and Shear Panel
- Dimensional Lumber Roofs
- Engineered Lumber Roofs
- Roof Trusses
- Structural Insulated Panels
- Seismic and Wind
- Steel
Stud Spacing
Maximum stud spacing for Standard or better-grade studs is shown in Figure A. Lower-grade 2x4 studs cannot exceed 16 in. o.c.
Figure A: Maximum Stud Spacing (in.)
Stud Size | 2x4 | 2x6 |
---|---|---|
Supporting Roof and Ceiling Only | 24 1 | 24 |
Supporting One Floor Roof and Ceiling | 16 | 24 |
Supporting Two Floors Roof and Ceiling | - | 16 |
Shall be reduced to 16 inches if Utility grade studs are used. Adapted from IRC Table R-602.3(5) ↩
Top Plates
Most model codes require loadbearing walls to have double top plates lapped so that the splices are at least 4 ft. apart. Two 16d nails are required on each side of the splice and additional nails are required every 24 in. in the overlap area (Figure B). See nailing schedules (Figure: Nailing Schedules in Nailing Rules of Thumb).
Figure B: Splicing Top Plates in Bearing Walls

Double vs. Single Top Plates
Single top plates are considerably weaker than a traditional double top plate. However, many codes permit single top plates as long as they are joined at splices, corners, and intersecting walls with .036-in.-thick galvanized steel plates, measuring 3x6 in. Plates should be fastened with six to nine 8d nails for corners and intersecting walls (depending on seismic zone) and 12 to 18 8d nails for joints in a straight wall (depending on seismic zone).
When using single top plates, rafters or joists must not be offset from studs by more than 1 1/2 in. (Figure C).
Figure C: Double vs. Single Top Plate

Maximum Stud Lengths
Studs used in exterior loadbearing walls, whether 2x4 or 2x6, should not be more than 10 ft. high without being engineered.
Engineered solutions include reducing stud spacing, using wider studs, doubling the studs, and using studs made from engineered lumber.
Notching and Boring Studs and Plates
Studs
When notching or drilling through studs under 10 ft. tall, follow the guidelines shown below.
Figure: Notching and Boring Regular Studs

Never make notches and holes across from one another in the same section of a stud. For studs over 10 ft. in height, follow guidelines shown below.
Figure: Engineered Studs for Tall Walls

Plates
If more than 50% of the width of a top plate is notched or drilled away, then the edge of the plate must be reinforced with a 16-gauge plate at least 1.5" high and extending at least 6" beyond the notch on both sides.