If your house has a wood floor over a crawl space, the “foundation” is really several separate parts: concrete pads under the interior posts, the posts themselves, a perimeter footing with a short concrete wall on top (the stem wall), and the wood sill plate bolted to that wall. When someone says the crawl space foundation needs repair, the first useful question is: which of those parts?
This post follows the repair of each part in turn. It’s about the concrete and the connections, not the whole project. For the project view (diagnosis, the permit fork, shoring, surprises, and closeout) read our raised foundation repair process. For moisture work and liners, see crawl space encapsulation vs repair and vapor barriers in crawl spaces.
The code sections quoted here are from the San Diego Residential Code (the California Residential Code with City amendments). They set minimums for new work. They don’t tell you what your particular house needs; an evaluation, and sometimes an engineered design, does that.
Before any concrete moves: confirm which parts failed and why
A sunken pad, a cracked stem wall, and a rotted sill can all show up upstairs as the same sloping floor. Floor elevation readings help sort them out: a dip in the middle of the house points toward interior supports, and a slope toward an outside wall points toward the perimeter. Our post on measuring uneven floors explains how those readings work, and footing damage homeowners can spot covers what to photograph at pads and footings.
The cause matters as much as the part. A pad that sank because the soil under it stays wet can sink again on new concrete if the water isn’t dealt with. That’s why the repair plan should name the cause next to each item, not just the item.
Step 1: Carry the floor before removing anything
Whatever is being replaced, the floor above it has to be held up by something else first. Temporary shoring posts or jacks go in beside the support that’s coming out. This is the step where a repair is safest to slow down. Nothing that carries load should be removed until its replacement support is in place.
Step 2: Interior pier pads and posts
Interior posts carry girders, and the girders carry the floor joists. Each post sits on a concrete pad (a small isolated footing). Replacing a failed pad means taking the load off the post, removing the post and the old pad, and building a new one.
Digging to firm soil. A new pad is only as good as the ground under it. Loose fill, debris, or soil softened by years of water isn’t a base for new concrete. How deep the crew has to go to reach firm ground, and how that’s confirmed, is one of the things that changes from house to house, and on some sites it’s a question for a soils engineer.
Sizing the pad. For concrete footings in general, R403.1.1 sets a floor of “not less than 12 inches (305 mm) in width and 6 inches (152 mm) in depth,” and adds that “the footing width shall be based on the load-bearing value of the soil.” Those are minimums. A pad under a heavily loaded girder, or on weak soil, may need to be larger, and a designer sets that size when the work goes beyond like-for-like replacement.
The post on top. R407.3 says columns “shall be restrained to prevent lateral displacement at the bottom end,” and that “wood columns shall be not less in nominal size than 4 inches by 4 inches.” In plain terms, a new post can’t just sit loose on its pad; it needs a connection that keeps the bottom from kicking out. (The code has a narrow exception for short posts in lower seismic design categories. Your designer will know which category applies to your house; don’t assume it.)
Inspection before the pour. City Information Bulletin 120 says: “All construction that requires a permit must be inspected before it is covered or concealed.” For a pad, that can mean the excavation is open and waiting for the inspector before any concrete goes in. One of the reasons the bulletin lists for failing an inspection is “Work has been concealed without inspection approval.”
Bringing the floor back. Once the new pad has cured and the post is connected, the load comes off the temporary shoring. Where the floor is being brought back toward level, that’s done gradually. Our raised foundation repair process post explains why a stable, improved floor is the usual goal rather than a perfectly flat one.
Step 3: Perimeter footing and stem wall
The perimeter is a different job. The footing and stem wall run continuously around the house and carry the outside walls. Damage here tends to show up as cracks, sections that have dropped or tilted, or concrete that’s crumbling at the surface.
Not every stem-wall crack calls for concrete work. Our posts on horizontal vs vertical foundation cracks and footing damage explain how to read them. When a section does need replacing or strengthening, the method is a design decision. It depends on how much is damaged, what the soil is doing, and whether the problem is the concrete or the support beneath it. Some repairs replace a length of wall and footing while the floor is shored; others add support below an existing footing, which is underpinning. Our posts on underpinning and pier methods compared cover the deeper-support side.
Depth is part of the design here too. For exterior footings, the code says they “shall be placed not less than 12 inches (305 mm) below the undisturbed ground surface” (R403.1.4). The word that matters is undisturbed: new perimeter concrete goes down to soil that hasn’t been dug up or filled, and on a slope or over old fill a designer may call for more.
When new continuous foundation goes in under a wood sill, the code’s anchorage rules apply to that new section. That’s the subject of the next step.
Step 4: Reconnecting the sill plate
The sill plate is the wood that sits on top of the stem wall and carries the wall framing. When a section of stem wall is replaced, the sill over it has to be anchored to the new concrete. R403.1.6 spells out the baseline:
- Anchor bolts at least 1/2 inch in diameter, “spaced not greater than 6 feet (1829 mm) on center,” or approved anchors or straps that give equivalent anchorage
- Bolts that “extend not less than 7 inches (178 mm) into concrete”
- Bolts “located in the middle third of the width of the plate,” with “a nut and washer” tightened on each
- “Not fewer than two bolts per plate section with one bolt located not more than 12 inches (305 mm) or less than seven bolt diameters from each end of the plate section”
The section also allows bolts to be set “while concrete is still plastic and before it has set,” so anchor layout is part of planning the pour.
In the higher seismic design categories, R403.1.6.1 adds more: “Plate washers conforming to Section R602.11.1 shall be provided for all anchor bolts over the full length of required braced wall lines except where approved anchor straps are used,” and it caps bolt spacing at 4 feet for buildings over two stories. Again, which category applies is a design question for your house.
Anchoring a sill to new concrete during a repair is different from adding bolts to an existing foundation as a seismic retrofit. The retrofit side, with its own standard plan set, is covered in our bolt-and-brace overview and on our seismic retrofit page.
Step 5: Clean up the crawl space
A repair isn’t finished when the concrete cures. R408.5 requires that “the under-floor grade shall be cleaned of all vegetation and organic material,” and that “wood forms used for placing concrete shall be removed before a building is occupied or used for any purpose.” Construction materials have to come out too.
Leftover forms, offcuts, and bags also make the next look at the crawl space harder, whether that’s your own check after a wet winter or a future inspection. Before you sign off, ask for photos of the cleared crawl space, or look from the hatch yourself.
Grade matters as well. R408.6 lets the under-floor grade sit at the bottom of the footings, but not where groundwater or surface water is a problem, unless an approved drainage system is provided. Our post on older La Jolla raised foundations explains that rule. If digging for new pads lowered the crawl space floor, it’s worth checking how water will move afterward.
Where the permit path fits
Whether this work can go ahead on a City No-Plan permit or needs drawings depends on what’s being done. Information Bulletin 203 allows “damage repair and replacement-in-kind (same size and specifications) when the existing structural framing system and life/safety elements are sufficiently intact for verification by the City inspector,” and requires “a pre-construction inspection” for those permits. A new girder line, larger pads, different post spacing, or a stem-wall redesign moves the job into plan review. Our raised foundation repair process walks through that fork, and our San Diego permit basics post covers the wider process.
If the work is under approved plans and something changes mid-job, IB-120 is clear that construction changes “shall be reviewed and approved by the City prior to being incorporated,” and that “a construction change does not extend your permit.”
Questions to ask about each repair item
When a proposal lists crawl space foundation work, ask for each item:
- Which part is it: pad, post, girder, stem wall, footing, or sill?
- What caused the damage, and what is being done about that cause?
- Is it like-for-like replacement or new design? If new, who designs it?
- How deep will new pads go, and how will the crew confirm firm soil?
- How will posts be connected at the bottom?
- For new stem-wall sections, how will the sill be anchored?
- Which City inspections apply, and when will work stop for them?
- What will be cleared out of the crawl space at the end?
Cost factors, not prices
We don’t publish prices. What shapes the scope of crawl space foundation repair: how many pads, posts, or stem-wall sections need work; how deep the crew has to dig to reach undisturbed soil; whether the work is in-kind or needs engineered design and soil input; anchorage and seismic requirements for new sections; how much shoring is needed; crawl space clearance and access (today’s companion post, access and working conditions that affect scope, covers those); moisture correction; inspections; and what turns up once things are opened.
Where we fit
We evaluate crawl space foundations on site for homeowners across La Jolla and explain which parts need work before we recommend a repair. When pads, footings, or stem walls need engineered design or soils input, we coordinate with licensed engineers as needed. Our crawl space foundation repair page describes the service, and our foundation repair and raised foundation repair pages cover the related work. This post is general education, not an engineering opinion about any specific house.
Next step
If your raised floor is sloping or an inspection report flagged pads, posts, or the stem wall, request a Free Quote for an on-site evaluation anywhere in La Jolla, or call (650) 739-6537. For footings on their own, see our footing repair page.
Sources (accessed October 21, 2026)
- San Diego Residential Code 2025 (California Residential Code with City of San Diego amendments), Sections R403.1.1, R403.1.4, R403.1.6, R403.1.6.1, R407.3, R408.5, R408.6
- City of San Diego Information Bulletin 120, How to Obtain Project Inspections
- City of San Diego Information Bulletin 203, No-Plan Building Permit