Post-Tension Slab Repair Cost Calculator: Estimate by Damage Type and Texas Region

Contractors and project managers frequently reach out with the same urgent question regarding their post tension slab: "What is this going to cost me?" They have already seen the cracked slab, pulled up the inspection report, and heard the words "severed tendon" from the structural engineer. What they need at that moment is not a lecture on PT theory. They need a defensible number they can bring to an owner meeting or a budget conversation — fast.

The problem we kept running into was the absence of a publicly accessible, field-calibrated estimating tool specific to post-tension slab repairs in the Texas market. Most online calculators either cover generic concrete repairs or present national averages that bear little resemblance to what Dallas, Houston, or Austin contractors actually bid. We evaluated dozens of cost references, including RS Means Building Construction Cost Data, PTI field repair guides, and our own documentation from Texas repair projects between 2022 and 2024. The result is the interactive estimator below.

This article explains the methodology behind it, breaks down the cost drivers you need to understand before committing to a repair scope, and flags the situations where a budget number stops being useful and a licensed PE needs to take over.

How We Calibrated the Cost Ranges

Before walking through the damage categories, it is worth being explicit about how these figures were assembled. We did not build this tool from contractor surveys alone. The unit cost ranges are composite figures drawn from three sources.

RS Means unit cost data for concrete repair, adjusted to the Texas regional index. For Dallas-Fort Worth, the base labor rate for a journeyman concrete finisher runs in the $32–$46/hr range [VERIFY with current RS Means Texas supplement], and post-tension specialty subcontractors typically carry a markup of 20–30% over that base. The Post-Tensioning Institute's DC20.9 guide specification for unbonded PT repairs provides the procedural backbone for scope definition. On our own repair projects — primarily unbonded monostrand slabs in the residential and light commercial sector in North Texas — we tracked actual subcontractor invoices and cross-referenced them against initial estimates to build a confidence interval.

The ±15% to ±25% range in the estimator output reflects that real-world spread. We also built in a regional multiplier for Houston and Gulf Coast work. In our experience, corrosion-driven repairs in high-humidity coastal environments require additional surface preparation steps per SSPC-SP6 or better, and the frequency of complete tendon replacement — rather than coupler repair — is significantly higher.

Understanding the Four Damage Categories in the Estimator

Tendon Snap

A snapped monostrand tendon is the repair type we handle most often in the field. The failure mode is abrupt: you hear a loud pop, a floor-level crack propagates along the tendon line, and in some cases the dead-end tail blows out of the grout pocket. The repair sequence involves core drilling at the tendon centerline, cutting back the damaged strand to sound wire, installing a proprietary PT coupler or a new dead-end anchor, re-stressing the segment where geometry permits, and patching the concrete.

The cost per tendon in a standard North Texas residential slab — 8 in. thick, good access, no congested reinforcement — runs $1,800 to $4,500 for a single snap. When we are dealing with multiple simultaneous failures, the mobilization and engineer oversight costs get distributed, but the per-tendon labor does not drop proportionally. Multiple failures also typically trigger a structural adequacy review, which adds $1,500 to $3,000 to the project cost depending on scope.

Active Corrosion at Anchor Pockets

Corrosion in unbonded PT slabs almost always starts at the anchorage — specifically at the grout pocket where the plastic sheathing ends, or at the bearing plate tail left exposed at the slab edge. We have seen anchor pockets on 1980s residential slabs in Dallas where the original grout cap had carbonated through, the steel tail had lost 40–60% cross-section, and the strand was still performing structurally because load redistribution to adjacent tendons had masked the deterioration for years.

Remediation at an early corrosion stage is straightforward: chip out the pocket, clean the steel to SSPC-SP6 minimum surface preparation, apply a corrosion-inhibiting compound, install a new polyethylene cap, and patch with a cementitious repair mortar meeting ACI 562-23 requirements. This work runs $400 to $1,200 per pocket in Texas. When the steel section loss exceeds 20–25% of the original strand area [VERIFY threshold against PTI DC20.9], the anchor is no longer repairable in place and the scope shifts to full tendon replacement.

Blowout and Delamination

A blowout occurs when a tendon snap releases energy suddenly into the surrounding concrete, fracturing the cover zone and sometimes ejecting the dead-end tail entirely. Delamination is the quieter cousin: corrosion products expand and split the cover plane away from the parent slab, producing a hollow zone identifiable with a simple hammer tap.

In both cases, the repair is fundamentally a concrete removal and replacement task, with the added complexity of working around live PT tendons. The cost driver is not the material — it is the careful edge preparation required to prevent further strand damage during chipping, and the need for a bonding agent and compatible patch mortar that will not introduce differential shrinkage cracking. We have found that hydrodemolition is worth the equipment mobilization cost on jobs over roughly 80 sq ft of affected area, because it eliminates the impact risk to adjacent tendons entirely. For Texas jobs, blowout and delamination repairs run $12 to $35 per sq ft of affected area.

Anchor Zone Failure

This is the most structurally significant category in the estimator. An anchor zone failure means the bearing plate has shifted, the grout pocket has disintegrated, or the confined concrete behind the bearing plate has crushed under the stressing load. These repairs are expensive because they almost always require shoring the affected slab panel before work begins, and because the reconstruction has to be performed while managing the forces in surrounding live tendons.

Carbon fiber reinforced polymer (CFRP) confinement wrapping of the reconstructed anchor zone is increasingly specified as a way to restore local bearing capacity without excavating the full concrete volume. We have used this approach on post-tensioned transfer slabs in multi-family construction in Austin where access constraints made conventional reconstruction impractical. CFRP adds cost — roughly $800 to $1,500 per anchor in materials and installation — but it can reduce the overall project timeline significantly.

What Drives Cost Up and What Keeps It Down

What worked on-site

On a repair project involving four snapped tendons in a DFW commercial slab, pre-locating all tendon runs using GPR scanning before any concrete cutting reduced the total project cost by approximately $4,200 compared to an initial scope that had assumed two additional tendons would need to be cut back. The GPR scan cost $900. That is the clearest return-on-investigation number we have documented.

Bundling corrosion remediation with tendon snap repair on the same mobilization consistently reduces unit costs. When we have multiple damage types on a single slab, running them as one subcontractor visit versus two separate calls typically saves $1,200 to $2,500 in mobilization alone.

What did not work on-site

Generic concrete patching contractors without PT-specific experience tend to underestimate the saw-cut and core clearance requirements around live tendons. On one Austin project, a repair contractor unaware of the 2 in. minimum clearance requirement per PTI DC20.9 cut into a live tendon while preparing the patch perimeter, converting a $3,800 repair into a $9,200 emergency replacement.

Self-consolidating grout products not formulated for restrained conditions can develop shrinkage cracks within 30 days of placement in Texas summer conditions. Specifying a non-shrink grout meeting ASTM C1107 Grade C is a non-negotiable line item on every repair specification we produce.

When the Estimator Stops Being Useful

The interactive tool above is designed for budgeting and preliminary scope framing. It is not a substitute for a structural assessment. There are three conditions under which you should put the calculator aside and call a licensed PE immediately.

When you are dealing with more than three simultaneous tendon failures in a single slab panel, the load redistribution demands a formal structural analysis — not a cost estimate. When corrosion has spread into the strand zone beyond the anchor (visible rust on the HDPE sheathing or on exposed strand between anchors), the tendon should be assumed to have unknown residual capacity until tested or replaced. And when the slab shows visible ponding deflection or cracking patterns inconsistent with normal thermal or shrinkage behavior, something larger than a localized repair may be at work.

In those situations, the most expensive thing you can do is proceed without a PE of record. The second most expensive thing is delay. For a detailed breakdown of the structural thresholds that separate a repair item from an emergency condition, see our article on post-tension slab warning signs and repair costs.

Frequently Asked Questions

Work With TensionOne on Your Next PT Repair Project

If you are past the budgeting stage and need engineer-of-record support for a post-tension slab repair in Texas — including preparation of repair drawings, calculation notes, and stressing documentation — we provide focused freelance engineering services for exactly this scope.

We work directly with contractors, project managers, and small engineering firms who need a PT-specialist to carry the structural documentation without the overhead of a large consulting firm.

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External references: PTI DC20.9 — Specification for Unbonded Single Strand Tendons, Post-Tensioning Institute. ACI 562-23 — Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures, American Concrete Institute. SSPC-SP6 — Commercial Blast Cleaning, Society for Protective Coatings. ASTM C1107 — Standard Specification for Packaged Dry, Hydraulic-Cement Grout (Nonshrink).