Where the Stakes Are Higher

A tendon under tension carries enormous stored energy. Cutting into a post-tensioned slab without knowing exactly where the tendons run is genuinely dangerous, and corrosion within a tendon is invisible from the surface until it fails. Both facts make this specialist work rather than ordinary concrete repair.

The other reason this is specialist work is that a damaged tendon changes how load moves through the structure around it. Repairing one is not a local operation — the engineer has to establish what the structure is doing without it before anybody decides how to put it back.

Corrosion inside a tendon is invisible from the surface. It is found by investigating the anchorages, by looking for the characteristic staining and cracking that a corroding tendon produces, and in some cases by opening up to inspect directly.

Because it is invisible, a garage can be structurally compromised while presenting far less surface damage than a conventionally reinforced one. That is worth understanding when comparing two garages that look similar from the deck.

1. 01Locate tendons before any cutting, every time.
2. 02Work to the engineer's repair design without deviation.
3. 03Engage specialist tendon contractors where required.
4. 04Shore and support to the engineer's requirements.
5. 05Document every repair for the structural record.

Anchorages are where post-tension corrosion concentrates, because that is where the tendon meets the outside world. They are frequently at the slab edge, exposed to exactly the conditions that cause corrosion, and they are the first place a competent investigation looks.

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