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Building Code Reference

Got a CRC R403.1 correction?

Foundation footing minimums

For builders in California, Greater Seattle, the Las Vegas area, the Denver area and Kansas City · CrossBeam Permits

What this code requires, how to fix it, and how cities and counties review it

What this code requires

CRC R403.1 sets the minimum requirements for continuous concrete footings under light-frame walls in California residential construction. Footings must be sized based on soil bearing capacity and the load they carry, with a minimum width of 12 inches and thickness of 6 inches for one-story buildings. The section also requires horizontal rebar reinforcement in both the top and bottom of the footing, anchor bolts at specified spacing with adequate embedment into the concrete, and plate washers where anchor bolts attach to the mudsill. In Seismic Design Categories D0, D1, and D2, which cover most of Orange County, the requirements get more specific on rebar size and placement.

How to fix it

  1. Show footing dimensions on the foundation plan

    On your foundation plan, call out the footing width and thickness explicitly for each wall condition. For a single-story wood frame wall, minimum is 12 inches wide by 6 inches thick assuming 1,500 psf soil bearing. For two stories with a crawl space, minimum is 15 inches wide by 6 inches thick. For three stories with a crawl space, 18 inches wide by 6 inches thick. Don't rely on a general note buried in specs — the plan-checker wants to see it dimensioned directly on the foundation plan, referenced back to a keyed detail. If you're using a geotechnical report, note the report number and the bearing value you're designing to.

  2. Add rebar callouts to the footing section detail

    Include a footing section detail at 1/4 inch equals 1 foot scale or larger that shows one No. 4 horizontal bar at the top and one at the bottom of the footing (with a stem wall: one within 12 inches of the top of the wall and one 3 to 4 inches from the bottom of the footing). Call out bar size, quantity, and placement. Show cover dimensions: 3 inches minimum where concrete is cast against earth, and 1-1/2 inches for No. 5 and smaller bars in formed concrete exposed to earth or weather. If the footing is deeper than the code minimum, your detail should still show both bars in the correct zones. Plan-checkers in OC jurisdictions will fail rebar review if the detail is vague or missing.

  3. Dimension anchor bolt spacing and end-of-plate placement

    On the foundation plan or a dedicated anchor bolt plan, show spacing at 6 feet on center maximum. Then add a separate note specifically calling out that bolts are placed within 12 inches of the end of every mudsill plate piece and within 12 inches of any splice or corner. If you have a 20-foot wall where 6-foot spacing works in the field, your end bolt may still be 18 inches from the plate end — that's a correction. Mark the end-of-plate bolt locations explicitly so the plan-checker can verify without measuring. On remodels tying into existing foundations, field-verify actual bolt locations and document them on the drawings before submittal.

  4. Specify 7-inch minimum embedment in the footing detail

    Anchor bolt embedment into concrete must be at least 7 inches, measured into the concrete, not through the sill plate. Show this dimension with a leader or dimension line in your footing section detail. Also call out the bolt diameter (1/2 inch or 5/8 inch is typical) and total bolt length so the inspector can verify during concrete placement. Bolts with less than 7 inches of embedment are a field rejection, not just a plan check comment — that means pulling permits for a repair pour if they're set short. Don't skip this callout.

  5. Add 3x3 plate washer spec for SDC D seismic zones

    In Seismic Design Categories D0, D1, and D2, standard cut washers are not code-compliant at anchor bolts along braced wall lines. Your footing detail and general notes must call out 3-inch by 3-inch by 0.229-inch (7-gauge) square plate washers at every anchor bolt in required braced wall lines (cut washers are allowed only in wall lines with no braced wall panels). Standard hardware-store washers are not acceptable substitutes. Add this callout to the footing detail section, the mudsill connection detail, and the general structural notes. If you're using a prefabricated anchor strap or hold-down instead of a conventional J-bolt, verify the product's ICC evaluation report specifies an equivalent washer or bearing plate.

  6. Reference soil bearing capacity or geotechnical report

    R403.1 ties footing sizing to soil bearing capacity. If you're using the presumptive bearing value, your general notes should state something like: 'Footings designed for 1,500 psf presumptive soil bearing capacity per Table R401.4.1(1). No geotechnical investigation on file.' If the project required a soils report, note the report title, author, and date on the foundation plan sheet, and confirm your footing sizing matches the report's recommended bearing value. Anaheim and Irvine plan-checkers frequently request this reference on the sheet, especially for ADUs with grading.

  7. Verify footing detail matches structural engineer's plan

    If you have a structural engineer of record, confirm their footing schedule matches what the architectural foundation plan shows. Discrepancies between sheets are a common cause of corrections — the plan-checker will compare them. If the structural plan governs, note that on the architectural sheet and cross-reference the structural detail number. If the structural plan shows a larger footing or additional rebar than R403.1 minimums, the structural plan controls. Submitting conflicting sheets creates questions that slow the review even if both sheets are technically correct.

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Why you got flagged

The most common reason plan-checkers flag R403.1 is that the foundation plan doesn't show enough detail to verify compliance. If your drawings just show a generic footing without calling out rebar size and placement, bolt spacing, or embedment depth, the plan-checker has no way to approve it. A note that says "footings per code" doesn't cut it.

Rebar callouts are a frequent miss. In SDC D0, D1 and D2, R403.1.3 requires at least one No. 4 bar near the top and one near the bottom of continuous footings. A lot of plans show the footing width and depth correctly but skip the rebar detail entirely, or they show a single bar in the center — that's a correction. The bottom bar sits 3 to 4 inches from the bottom of the footing, and your detail should show that explicitly.

Anchor bolt spacing catches a lot of contractors, especially on remodels where the existing foundation is being used. R403.1.6 requires anchor bolts at 6 feet on center maximum, within 12 inches of the end of each plate piece, and within 12 inches of a splice or corner. When a contractor dimensions the anchor bolts but doesn't call out the end-of-plate requirement, the plan-checker will red-line it.

Plate washers trip up plans in seismic zones. In SDC D0 through D2, the mudsill anchor bolts along braced wall lines require 3-inch by 3-inch by 0.229-inch plate washers. A lot of drawings either omit plate washers entirely or only call for standard cut washers. The plan-checker knows the difference and will flag it. If you're in a higher seismic zone, the washer spec is non-negotiable.

The official code

California Residential Code Chapter 4 — Foundations (DGS Building Standards Commission)

Read the source →

Common questions

What size rebar does CRC R403.1 require in footings?
In SDC D0, D1 and D2, R403.1.3 requires at least one No. 4 (1/2-inch diameter) bar placed in the top portion of the footing and one No. 4 bar in the bottom portion. Both bars run horizontally the length of the footing. With a stem wall, the top bar sits within 12 inches of the top of the wall and the bottom bar 3 to 4 inches from the bottom of the footing, with minimum 3 inches of cover where the concrete is cast against soil. If the footing is deeper than the minimum to meet R403.1.4 frost depth or grading requirements, the bar placement zones shift with the footing depth. In Seismic Design Category D zones, section R403.1.3 adds requirements on top of these basics — check both sections.
How far apart do anchor bolts have to be per R403.1?
Maximum spacing is 6 feet on center. But that's not the whole requirement. You also need a bolt within 12 inches of the end of every mudsill plate piece. That means each time a plate ends — at a corner, a splice, a cripple wall transition — the nearest bolt has to be within 12 inches of that plate end. If your wall is 22 feet long and you set bolts at 0'-11", 6'-11", 12'-11", 18'-11", and 21'-1" (within 12" of the end), that pattern works. A lot of corrections happen because the contractor spaces bolts at exactly 6 feet and the last one ends up 16 inches from the plate end — that's non-compliant regardless of total count.
Do I need plate washers on anchor bolts in Orange County?
Yes. Orange County is in Seismic Design Category D0 through D2 depending on the specific location and the project's risk category. SDC D zones trigger the plate washer requirement in R403.1. You need 3-inch by 3-inch by 0.229-inch (3x3x7ga) steel plate washers at each anchor bolt — standard cut washers or fender washers are not acceptable. Some contractors use code-listed hold-down anchors or structural screws for shear walls, which have their own bearing plate requirements in the manufacturer's ICC evaluation report. But for conventional J-bolt connections at the mudsill, the 3x3 plate washer is the standard.
Can I use an existing footing if I'm adding a room addition?
Possibly, but you have to verify it meets current R403.1 requirements. The plan-checker will want documentation. You'll need to expose a section of the existing footing to confirm actual dimensions, rebar size and placement, and anchor bolt spacing. If the footing was poured decades ago without seismic plate washers or adequate rebar, you have a few options: add a new continuous footing alongside the existing one, install seismic anchors with core-drilled epoxy bolts to supplement spacing, or demonstrate via a structural engineer's evaluation that the existing footing is adequate. Don't just note 'existing footing to remain' — that will get flagged immediately.
What embedment depth does R403.1 require for anchor bolts?
Anchor bolts must be embedded at least 7 inches into the concrete. That measurement is taken from the top of the mudsill bearing surface down to the bottom of the bolt in the concrete — not from the top of the bolt above the mudsill. Show this dimension on your footing detail. In practice, most contractors use 10-inch J-bolts to allow for the mudsill thickness plus nut and washer above, which gives closer to 8 or 9 inches of embedment. Bolts set short in the field — under 7 inches — are a failed inspection. The fix requires core-drilling and epoxy-setting replacement bolts, which is expensive and slow.
What's the minimum footing width for a two-story house in California?
For a two-story wood-frame house with a soil bearing capacity of at least 1,500 psf, Table R403.1(1) requires footings at least 15 inches wide and 6 inches thick with a crawl space (13 by 6 on a slab). For three stories, the minimum increases to 18 inches wide and 6 inches thick with a crawl space. These are the code minimums assuming the standard presumptive bearing value from R401.4.1. If your site has a geotechnical report showing lower bearing capacity, you'll need wider footings regardless of code minimums. Also confirm the depth meets R403.1.4 — footings should extend at least 12 inches below undisturbed soil in most California locations.

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