What is the minimum sill plate size?

What is the minimum sill plate size?

• A. 2x4
• B. 2x6
• C. 1x4
• D. 3x4

Answer: (A)

The sill plate must provide a solid base to transfer load from the wall to the foundation and to give a reliable surface for anchoring the wall framing. It has to be thick enough to resist bending and to hold nails or bolts securely. In typical residential construction, the smallest standard size that still reliably supports these duties is 2x4. A 1x4 would be too thin to hold fasteners and resist the forces the wall experiences, and 3x4 isn’t a standard stock size for this use. A 2x6 could be used, but it’s larger than necessary for minimum requirements. So, the minimum sill plate size is 2x4. (Note: treat it if it’s in contact with concrete.)

The sill plate must provide a solid base to transfer load from the wall to the foundation and to give a reliable surface for anchoring the wall framing. It has to be thick enough to resist bending and to hold nails or bolts securely. In typical residential construction, the smallest standard size that still reliably supports these duties is 2x4. A 1x4 would be too thin to hold fasteners and resist the forces the wall experiences, and 3x4 isn’t a standard stock size for this use. A 2x6 could be used, but it’s larger than necessary for minimum requirements. So, the minimum sill plate size is 2x4. (Note: treat it if it’s in contact with concrete.)