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A 25 year old Florida building's rebar is pushing out. The thick red line shows where the rebar is detached from the concrete (and theoretically could be clipped / removed). Thin red line shows the cracking caused by the rebar.

The tentative plan is to apply stucco over the rebar. Goals include remedying the problem so as to: ensuring that after the repair, the rebar does not push out any stucco. When all said and done, I would like the repair to be durable and not have to re-visit the problem in the next 120 months.

In the repair process, what is it necessary to pin the rebar and then stucco over the pinned rebar? The concern is that pinning will only repeat the cycle and I would expect a crack in the near future (24 months). I am concerned that cutting out the short section of rebar is difficult. Is releasing the rebar as is and applying concrete then stucco the better solution or better to cut off the rebar that is not attached to the concrete?

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Update: Pinned the rebar end with Tapcons so as to ensure it would not unfurl any father.

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gatorback
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    I don't think I've ever seen rebar in stucco. I'd guess that this is a stucco-over-foam situation, where there would be wire mesh behind. Why do you say "rebar"? (Also, I don't think there no concrete involved. Am I wrong about that?) – isherwood Dec 10 '21 at 13:50
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    Rebar should have 2-3" of concrete cover to protect it from excessive corrosion, so this does seem more likely to be wire mesh in stucco. – Ecnerwal Dec 10 '21 at 14:04
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    Since you're going to be repairing it - why not chip off some more loose stucco to get a better view into what's happening inside there? – brhans Dec 10 '21 at 14:06
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    That looks more like a galvanized corner or channel covered with stucco. You need to chip away a lot more to see what's actually going in there. – JACK Dec 10 '21 at 15:21
  • Closeup photos added to OP – gatorback Dec 10 '21 at 17:10

1 Answers1

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Whatever the metal is (rebar or wire mesh), it's rusting. As it rusts, it's expanding and that's why it's pushing the stucco out.

To make a long term fix, you'll have to pull out the rusting metal and replace it.

Based on the recently added close up pics, that does look more like some sort of corner angle than either rebar or wire mesh. In any case, it will need to be exposed, cleaned up and protected, or, even better, replaced. You may get the outside cleaned and protected, but the inside could continue to rust, pushing into the wall, loosening what's behind it, or pushing the corner out through the new layer of stucco.

Make sure the new material is well coated for protection against wet/damp environments, possibly with a coating that's specified for stucco/concrete use. With proper prep, the repair should last at least the desired 10 years. Without it, it might not make the 2 year mark.

FreeMan
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    And also figure out WHY it's rusting. You have water intrusion somewhere. If you replace the rebar but don't prevent the new rebar from rusting, then the problem will just happen again. – longneck Dec 10 '21 at 15:28
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    stucco is a water sink. There is always water in it. rebar should have 2" coverage of concrete on all sides to prevent oxygen from getting at it. I don't think rebar it the right material for this assembly. – Fresh Codemonger Dec 10 '21 at 18:08