WHILE REMOVING LOOSE STUCCO from the foundation wall (a/k/a stem wall), the waterproofing crew exposed at least 4 new instances of spalling concrete along the wall. This was not unexpected.
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This post describes the situation and the planned repair procedure, based on recent experience.
Here are photos of the newly uncovered wounds in the stem wall.
Why are these repairs needed?
The cracked concrete and missing concrete now need to be restored, so as to create a smooth and stable wall surface. But first the metal corrosion needs to be stopped, or else the cracking may return.
How is the repair carried out?
In May, while Kaptive Construction (a concrete contractor) was on site rebuilding certain pilaster bases, they uncovered the first instance of spalled concrete in the stem wall itself. The opening exposed not only rebar but also the end of a girder.
To repair the damaged spot, they took the following steps:
1. Chip out all loose concrete around the opening, to make a solid bonding surface.
2. Wire-brush the loose rust off of the exposed metal.
3. Coat the metal with a rust-inhibiting compound (as is standard practice nowadays in new construction).
4. Cover the exposed metal with a layer of Sika Armatec-110 (a premium epoxy cement that functions as a bonding primer and corrosion inhibitor). [For the manufacturer’s product data sheet and instructions, see HERE.]
5. Apply a cement patch, and smooth it to align with the wall surface.
Given the necessary allowance for curing time of the applied materials, patching that one spot was a full day’s work. Happily, because the crew was already working on site in the vicinity, we were charged only for an additional 2 hours of labor. Likewise they did not charge us for the Rapid Set cement (a high-strength mortar for structural repairs), because they had leftover material on site. Total cost of the repair: $453.60.
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