QUICK TAKEAWAY
Primary Insight: Commercial concrete repair cost is governed by how deep the deterioration runs, not how large it looks on the surface. Damage confined to the upper third of the slab can be patched, and damage past that line requires full-depth removal and replacement.
Key Fact: Caltrans qualifies joint spalling for partial-depth repair only when it extends less than 6 inches from the joint and less than 2 inches deep, and rules out partial-depth repair entirely once reinforcing steel is exposed.
Best Suited For: Property managers, facility directors, and commercial property owners in San Jose and the greater Bay Area comparing concrete repair bids that came back at very different numbers.
Two contractors can look at the same cracked slab and return quotes that differ by an order of magnitude, and both can be right. The number is not set by the square footage of the damaged area. It is set by how far down the damage goes, which is not visible from standing height.
Concrete repair guidance draws a hard line at the upper one-third of the slab. Deterioration that stays above that line is a surface problem with a surface fix. Deterioration that crosses it becomes a structural problem requiring removal and replacement of the full slab thickness, along with everything that implies for closure time, equipment, and cost.
This post covers where that line sits, what qualifies on either side of it, why a quote can change after demolition begins, and how a contractor should be establishing depth before putting a number on paper.
Three Levels of Concrete Work at a Glance
| Scope | Depth of Deterioration Addressed | Qualifying Criteria in Caltrans Guidance | What Rules It Out |
|---|---|---|---|
| Partial-depth repair | Localized distress that does not extend beyond the upper one-third of the slab. | Low severity spalling or scaling; joint spalls less than 6 inches from the joint and less than 2 inches deep. | Exposed steel, full-thickness cracks, or spalls extending more than 6 to 10 inches from the joint. |
| Full-depth repair | Deterioration running below the upper third, through the full slab thickness. | Transverse and longitudinal cracks, joint spalling, and blowups; minimum repair length typically 6 feet. | Not applicable as a partial measure; Caltrans does not allow half lane width repairs due to instability. |
| Full replacement | Deterioration widespread enough that isolated repairs stop being economical. | FHWA notes that areas requiring multiple partial-depth repairs are more cost effectively addressed by full-depth repair or overlay. | Isolated, well-defined damage on an otherwise sound slab. |
Depth of Deterioration, Not Surface Area, Sets the Scope
Depth of deterioration sets the scope of a concrete repair, and the threshold is the upper one-third of the slab. Caltrans defines partial-depth repair as the restoration of localized surface distresses that do not extend beyond that upper third, involving removal of small unsound areas and replacement with suitable repair material.
Everything past that line changes category. Caltrans directs that when deterioration extends below one-third of the slab depth, the work becomes a full-depth repair, which means removing the full slab thickness and casting a replacement in place rather than patching a surface.
The cost consequence follows directly from the method. A partial-depth patch is a small, shallow, fast operation. A full-depth repair is slab removal, base preparation, load transfer, and a new pour, which is why the same visible spall can generate wildly different numbers depending on what sits underneath it. Any credible commercial concrete bid should tell you which of the two it assumes.
What Qualifies for a Partial-Depth Repair
Partial-depth repair qualifies for localized surface distress on a slab that is otherwise sound. Caltrans applies it to low severity spalling and to small areas with scaling problems, and sets a specific threshold for joint spalling: less than 6 inches from the joint and less than 2 inches in depth.
Repair boundaries extend past the visible damage. Caltrans requires that partial-depth repair boundaries reach 2 to 6 inches beyond the delaminated or spalled area, which means the finished patch is always larger than the hole that prompted it. A bid that measures only the visible spall has underestimated the removal area.
Severity moves the line quickly. Caltrans states that partial-depth repairs are not appropriate for moderately severe spalls generally extending more than 6 to 10 inches from the joint, because spalling at that scale typically indicates further damage below. The same depth logic governs work on concrete curb and gutter and other flatwork elements on a commercial site.
What Forces a Full-Depth Repair or Replacement
Exposed reinforcing steel forces a full-depth repair. Caltrans states that cracks extending through the full thickness of the slab, and spalls with exposed reinforcing steel or load transfer devices, cannot be corrected with a partial-depth repair, and that a full-depth repair should be used in these cases.
Cause matters as much as depth. Caltrans notes that spalls caused by material problems such as D-cracking or alkali-silica reactivity, or by lockup and corrosion of dowel bars, cannot be addressed by partial-depth repairs, because those distresses usually indicate deterioration extending beyond the upper one-third of the slab.
Scale eventually overrides both. FHWA notes that partial-depth repairs are only cost effective where deterioration is not too widespread, and that areas requiring multiple partial-depth repairs can be repaired more cost effectively through full-depth repairs or overlays. At that point the honest recommendation stops being a repair and becomes a replacement scope.
Why an Estimate Can Change After Demolition Starts
An estimate can change after demolition starts because the deciding variable is hidden until concrete comes out. Caltrans lists more deterioration below the surface than is evident above as a documented troubleshooting scenario, with the prescribed solution being to extend the repair limits into sound concrete and convert to a full-depth repair if deterioration runs below one-third of the depth.
Exposed steel triggers the same conversion mid-job. Caltrans guidance directs that if reinforcing steel appears in the upper third of the slab it can be removed to the edges of the patch and the partial-depth repair continued, but if removal extends to the mid-depth of the slab, the work becomes a full-depth repair.
Well-run projects plan for this in advance rather than treating it as a change order dispute. Caltrans project checklists advise agreeing on quantities while allowing flexibility if additional deterioration is found below the surface, and note directly that some partial-depth repairs may become full-depth repairs. A contractor who raises that possibility before starting is describing standard practice, not hedging. The same principle applies to ADA ramp work, where compliance depends on the finished geometry holding up.
How Repair Depth Should Be Established Before Quoting
Repair depth is established through sounding and coring, not visual inspection alone. Caltrans directs that a visual survey be paired with engineering judgment, coring, load-deflection studies, and sounding techniques such as striking the concrete surface with a hammer or steel rod, or dragging a chain, to define the extent of deterioration beneath the surface and determine repair boundaries.
Sounding is the field method that finds delamination. A hollow response under a hammer or chain identifies concrete that has separated below an intact-looking surface, which is precisely the condition that turns a modest-looking patch into a full-depth repair once work begins.
Caltrans also advises that the survey be performed as close as possible to the proposed repair work and include distressed areas that have developed since the previous inspection. On an active commercial property with continuous traffic, a survey done months before the work is a survey that has aged. That is worth confirming when scheduling concrete work in San Jose or anywhere across the Bay Area.
When the Repaired Area Can Reopen
A repaired area reopens once the patch material reaches its specified strength, not once it looks solid. Caltrans notes that a compressive strength of 3,000 psi is generally specified by most agencies before a repair area is opened to traffic, and that measuring actual strength is preferable when very early opening is required.
Material selection is largely a closure-time decision. Caltrans most often uses rapid strength concrete for partial-depth repairs, and offers a practical rule of selecting the most convenient material that meets the lane closure requirements. For a commercial property, that translates into choosing the material that fits the hours the area can be fenced off.
Weather narrows the window further. Caltrans guidance holds that portland cement concrete and most proprietary repair materials should not be installed when air or pavement temperatures fall below 40 degrees Fahrenheit or on wet substrates, and that placement below 55 degrees requires warm water, insulation covers, and longer curing periods.
Frequently Asked Questions About Commercial Concrete Repair
Why do concrete repair quotes vary so much for the same visible damage?
Concrete repair quotes vary because the price is driven by the depth of deterioration rather than the size of the visible damage. A spall confined to the upper third of the slab qualifies for a partial-depth repair, while the same spall extending deeper requires full-depth removal and replacement, which is a different scope of work entirely.
Can spalled concrete be repaired instead of replaced?
Spalled concrete can be repaired when the deterioration stays within the upper one-third of the slab. Caltrans guidance qualifies joint spalling for partial-depth repair when it extends less than 6 inches from the joint and less than 2 inches in depth, and directs that deeper or more extensive spalling be handled with a full-depth repair.
What does it mean if rebar is showing in a concrete slab?
Exposed reinforcing steel rules out a partial-depth repair. Caltrans states that spalls with exposed reinforcing steel or load transfer devices cannot be corrected with a partial-depth repair, and that if removal reaches the mid-depth of the slab, a full-depth repair is required instead.
How soon can a repaired concrete area be reopened to traffic?
A repaired concrete area reopens once the patch material reaches its specified strength. Caltrans notes that most agencies specify a compressive strength of 3,000 psi before opening a repair to traffic, and rapid-setting materials are selected specifically to shorten that closure window.
Is asphalt patching an acceptable repair for a concrete slab?
Asphalt patching is not an acceptable permanent repair for concrete. Caltrans states that bituminous materials are not recommended for permanent repairs of rigid pavements because they allow excessive horizontal slab movement, provide no load transfer across the joint, and may lead to rapid deterioration, which limits them to short-term use.
Getting a Number You Can Actually Budget Against
A concrete repair quote is only as reliable as the investigation behind it. A number produced from a walkthrough describes the surface; a number produced from sounding and coring describes the slab, and only the second one survives contact with a jackhammer.
The questions worth asking a bidder are narrow: how was depth determined, which repair method does the price assume, and what happens to the number if deterioration runs past the upper third. EARTHTEK scopes commercial concrete repair across San Jose and the greater Bay Area on that basis, because a bid built on a guess about depth is a change order waiting to be written.
For residential slabs the same logic applies at smaller scale, and concrete patio repair cost covers that side. For a commercial property, request a concrete assessment from EARTHTEK and get the depth question answered before the bids come in.
