Replacing Damaged Stucco
Posted Jan 17th 2014 | By:
Stucco is one of the most long-lasting, low maintenance materials one can use in house building, but every once in a while, something goes wrong. It could be a crack or the stucco may even buckle, but when it happens, it requires immediate attention. Cracks and buckling are signs that water has found its way into places where it does not belong, possibly damaging underlying wood lath. Once you have this type of problem on your hands, it is mandatory that you fix it as soon as possible.
When planning to work with stucco, always take note of the weather. Ideally, stucco work should be done in mild weather that is not too hot or too cold. Do not forget that alkalis are present in wet cement and can burn your skin, so always wear gloves when handling stucco in addition to protective eye wear. If stucco accidentally gets on your skin, wash it off immediately.
The first step in repairing damaged stucco is to get rid of it, right down to the very last damaged grain. With your eye protection in place, begin removing the flawed stucco with a hammer and cold chisel. Do this gingerly so as not to damage the wood lath below, but be thorough at the same time, only stopping when you reach stucco that appears healthy and is firmly in place. Remove any underlying mesh or builder's paper at this time.
Now that the old, rotten stuff has been removed, it is time to begin the process of replacing it. First, affix a couple layers of new sheets of builder's paper in the area where you removed the last sheet and damaged stucco. Then you will need to replace your metal mesh in the same fashion, trimming it to fit with metal snips and tacking it firmly in place with roofing nails.
Mix the stucco patch of your choice according to the manufacturer's instructions. Once it is ready for use, wet down your existing stucco for a better bond and begin putting the new stucco in place. This can be done with a stucco float or brick trowel by scooping it on and smoothing it in place. Once your metal mesh is covered, pack your stucco down tight and keep adding more until your surface area starts to build outward. If you are patching a large, thick area, it is best to do so in layers, so if you have more than an inch of stucco to replace, stop half way through and plan to resume your task in a few days' time. In the meantime, score your stucco so the next layer will adhere to it more easily and cover it with plastic.
When it is time to apply your next coat, repeat the process of preparing your stucco and again affix it with a brick trowel. If you are within a half an inch of achieving evenness with the rest of the stucco, it is reasonable to expect to finish the job with two applications. If more than that remains, stop and again hang plastic over the scored stucco while it dries, then repeat the application process in a few days. However, if you are at a stopping point as far as applications go, you will need to attempt to match the texture of your existing stucco. This can be done by making sweeping motions with your brick trowel to create texture or by flicking pieces of stucco from the trowel onto the repair site.
Once your stucco has dried, all you have left to do is cover it with pigmented coating such as mineral paint, concrete paint or stain, or lime wash, but these items must be permeable by water vapor and alkaline tolerant or else they will peel. The application of new stucco will rarely if ever match the color of the old, existing stucco, so utilizing one of these options will conceal your patch. With your final application complete, allow it to dry and resume life as normal with healthy, attractive stucco once again in place on your home.
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