Post-tensioned concrete dominates South Florida's mid-rise and high-rise residential construction from the 1970s onward. When a milestone inspection report or 40-year recertification finding identifies post-tensioning deficiencies — corroded anchors, deteriorated sheathing, or broken strands — the repair process involves a level of engineer-contractor coordination that goes well beyond a conventional spalling patch. The engineer is not just a reviewer; they are a decision-maker at every stage. Understanding that sequence helps boards and property managers know what questions to ask, what documentation to request, and what it means when a stage has been skipped.
Stage 1 — Controlled demolition and tendon exposure
The engineer's report identifies suspect bays or zones based on visible corrosion evidence: spalling concrete above a tendon path, rust staining at the slab edge, anchor corrosion at the dead-end or stressing-end pocket, or an active tendon blowout. The contractor begins by saw-cutting the concrete boundary of the repair area. This is controlled demolition — the saw cut stops before reaching the tendon, and the remaining concrete over the strand is removed by hand chisel to avoid damaging the strand, the duct, or the anchor assembly. When the tendon is fully exposed, work stops. The contractor documents the location and photographs the exposed tendon and anchor condition. The engineer performs a field visit before any repair work begins, inspecting the strand for section loss or fracture, the sheathing for continuity, the corrosion-inhibitor grease in an unbonded tendon system, and the anchor hardware at both the stressing end and the dead end. No repair work proceeds until the engineer has performed this inspection and issued a field directive.
Stage 2 — Field directive and repair method determination
After inspecting the exposed tendon, the engineer issues a written field directive specifying the repair method for each location. The directive is the governing document for every subsequent step. If the strand is intact and the corrosion is limited to the sheathing, the anchor pocket coating, or the end cap at the dead end, the directive may call for re-greasing and re-sheathing the exposed strand, replacing the anchor cap, and placing a patch over a sound tendon with no structural intervention. If the strand has fracture, significant section loss, or pitting beyond the threshold in the engineer's specification, the directive calls for tendon repair or replacement — either a partial-length mechanical repair using a new anchor assembly connected to the undamaged strand section, or in severe cases, a full-length tendon replacement. The field directive also specifies the patching mortar by product name or performance specification — a rapid-setting cementitious mortar with a defined compressive strength, shrinkage limit, and chloride threshold. The contractor does not select the repair mortar. The engineer selects it. Any proposed substitution requires written approval before placement.
Stage 3 — Tendon repair and concrete reinstatement
For locations where the strand is intact, the repair sequence is: mechanically clean the exposed steel, apply the rust inhibitor specified by the engineer, replace or repair the sheathing around the strand, inject fresh corrosion-inhibitor grease in the unbonded section, and place the patch mortar in lifts as specified to control shrinkage. For locations where the field directive calls for tendon repair involving new anchor hardware or strand replacement, the sequence adds cutting of the damaged section, installation of the replacement anchor assembly, and stressing of the repaired tendon to the specified load before concrete is placed over it. Stressing is performed with a calibrated hydraulic jack. The jack reading — in PSI correlated to elongation in inches — is recorded for each location and submitted to the engineer as part of the stressing log. The engineer reviews the stressing log and typically performs an interim field inspection to confirm the anchor hardware, the strand condition, and the applied load before the concrete patch is placed. The patch is not placed until the engineer approves.
Stage 4 — Documentation, closeout, and the re-inspection report
When all repair locations are physically complete, the contractor assembles a closeout package and delivers it to the engineer before requesting final payment. The package includes the field inspection log for each tendon location, the stressing log for any locations where a tendon was repaired or retensioned, material data sheets for the patch mortar and corrosion inhibitor, any photographic documentation required by the engineer's specification, and a location map correlating each repair location to the original report's finding reference. The engineer reviews the package, performs a final walk of all repair locations, and issues the signed re-inspection report confirming that the work corrected the deficiencies identified in the original milestone inspection or recertification report. That re-inspection report is the permit closeout document. The building department inspector accepts it to close the permit. The county's compliance file requires it for milestone inspection or 40-year recertification satisfaction. A contractor who requests final payment before the engineer has issued that report is requesting payment before the project is contractually complete — regardless of what the physical work looks like.
- Do not allow concrete to be placed over an exposed tendon before the engineer's field inspection
- Require the stressing log as a deliverable — not an optional record
- Confirm the engineer of record will issue the final re-inspection report, not a different engineer
- Tie final payment to delivery of the engineer's signed re-inspection report and permit closeout