Sill-plate anchor bolts: ½ in diameter, ≤ 6 ft o.c., ≥ 7 in embedment, ≥ 2 per plate section
2025 RCNYS §R403.1.6 Foundation anchorage (sill plates)Description
Wood sill plates resting on continuous foundations must be anchored with ½-in-diameter (minimum) anchor bolts spaced at most 6 ft o.c., embedded at least 7 in into concrete or grouted masonry. Bolts must be located in the middle third of the plate width with a nut + washer tightened on each. At least 2 bolts per plate section, with one bolt within 12 in (but ≥ 7 bolt-diameters) of each end. Seismic Design Categories D0/D1/D2 and townhouses in Category C require plate washers along braced wall lines; max bolt spacing drops to 4 ft o.c. for buildings 3+ stories.
Why this exists
Sill anchorage transfers wind + seismic shear from the dwelling to the foundation. Under-bolting is one of the most common construction defects in older homes, leading to slab-off-foundation displacement in earthquakes. Architects should call out the sill bolt schedule + washers on the structural drawings — don't rely on the contractor's default.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
boltDiameter | min | 0.5 | in | Anchor bolt minimum diameter |
maxSpacing | max | 6 | ft | Maximum bolt spacing (single-story) |
maxSpacing3Story | max | 4 | ft | Maximum bolt spacing (3+ stories) |
embedment | min | 7 | in | Minimum bolt embedment into foundation |
minPerSection | min | 2 | bolts | Minimum bolts per plate section |
Categories
Applies to
- Jurisdiction: New York State
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
- Garage / dwelling fire separation · IRC R302.6
- Habitable space minimum ceiling height · IRC R305.1
- Egress window net opening dimensions · IRC R310.2
- Stair riser, tread, and headroom · IRC R311.7
- Smoke alarms required throughout dwelling · IRC R314
Last reviewed 2026-05-15.