Almost all stem wall repairs leave the home vulnerable to up lift damage… why is that?
In my previous blog http://www.foundationaz.com/blog/why-many-of-our-repairs-of-stem-walls.html, I discussed the basic problem of stem wall rebar rust deterioration. This is a pervasive problem. We see whole neighborhoods where the stem walls are deteriorating. This is a permanent and progressively deteriorating condition. In the previous post I raised the problem of rusting rebar, however this is not the only problem. There are also issues with the tie down straps and the J bolts.
The current International Concrete Repair Association repair protocol calls for cleaning the rusted steel to white metal, coating with an ion blocking epoxy and patching back with an anodic enhanced repair mortar. While these measures are effective, they are not permanent. Experts agree that at some point, the oxidization will resume and unabated, eventually destroy the concrete.
This is also true for the hold down straps and J-bolts. The hold down straps extend from the stem wall concrete up though the framing about 24”. These straps are thin and deteriorate easily. When we encounter them, they are almost always completely gone. Replacing these straps are difficult at best. It involves either removing and replacing the stucco on the outside or the drywall on the inside, trying to match textures and colors. Only to have the oxidization process continue and deteriorate the new straps and bolts at an accelerated rate since the chloride ion migration would then be in full swing. This is especially true considering that the way the straps are installed is with zero concrete coverage on the top where it exits to attach to the wood stud. (where it accelerates corrosion more).
Until recently, most contractors have ignored the problem. Not replacing the straps is common as it is usually so deteriorated that it can hardly be detected. J-bolts are similar in that they also extend up through the bottom plate and again, requiring removal and replacement of either the stucco or drywall. The end result is that the hold-down capacity is severely reduced or eliminated. This means that any severe storm with strong winds could in fact shift the house from its foundation.
We as a team have worked very hard on these problems and have come up with some revolutionary solutions. We have applied for a provisional patent while we apply for the permanent patent.
Stay tuned for the details!
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