Sill-plate anchor bolts: 1/2" diameter @ 6 ft on-center, max 12 inches from corners/splices
HUD RSDG §7.4.3Description
Anchor bolts connecting the sill plate to the foundation are typically 1/2" diameter, embedded 7" minimum into concrete (or 15" into masonry grout), spaced no more than 6 ft on center, with at least one bolt within 12 inches of each plate end + each side of every splice. A 2x2x3/16" plate washer is required for braced wall lines in seismic categories D0+ per IRC R602.11.
Why this exists
Sill anchorage is the load-path step that transfers lateral + uplift forces from the wood frame into the foundation. Insufficient bolting is a documented failure mode in seismic events (homes slide off foundations) and high-wind events. The 6-ft spacing is the IRC R403.1.6 default; SDC D0+ tightens it.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
boltSpacing | max | 6 | ft | Maximum anchor-bolt spacing |
cornerDistance | max | 12 | in | Maximum distance from corner / splice |
boltDiameter | min | 0.5 | in | Anchor bolt diameter |
embedmentConcrete | min | 7 | in | Minimum embedment in concrete |
Categories
Source
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Continuous load path from roof to foundation · HUD RSDG §2.4
- Residential structural reliability targets 1-in-100 to 1-in-1000 annual probability of failure · HUD RSDG §2.5
- Residential floor live load: 40 psf minimum (30 psf sleeping rooms) · HUD RSDG §3.4
- Wind load design uses ASCE 7 basic wind speed for the locality · HUD RSDG §3.6
- Ground snow load for Virginia: 25 psf eastern, up to 40 psf western mountains · HUD RSDG §3.7
Last reviewed 2026-05-14.