Cleaning Masonry

If you’ve come up against a stone wall trying to clean brick in areas at the exterior of your home such as patios, walkways, walls or a chimney then you really should read on.

The three most common masonry cleaning problems are: 1) fungus, moss and mildew, 2) oils, soot and mineral residue, and 3) paint.

Unless your home can be confused with an ancient English castle, engulfed by several hundred years of root growth, fungus, moss and mildew are really a breeze to clean. A quart of household liquid bleach mixed into a gallon of warm water applied with a stiff bristle brush usually does the trick. Sodium hypochlorite, the active ingredient in bleach, might not dissolve large masses of these types of growths. In such cases, it is wise to harvest the excess product by first scraping it off with a broad-bladed putty knife (or wire brush). Then, scrub on the killer mixture – and simply rinse the problem away. Remember: even though this is a relatively mild solution, don’t forget eye protection, rubber gloves and protective clothing.

Oils, soot and white, powdery mineral residue pose a slightly more difficult problem. Characteristically, they are embedded more deeply into the pores of the masonry than moss and mildew. And, although bleach can be used effectively in some instances – it usually isn’t adequate.

Can you spell “we need something stronger”? We can “m-u-r-i-a-t-i-c a-c-i-d”. And all you need here is a ten-percent solution. That’s one part muriatic acid to nine parts water. Add the acid to the water, use a bristle brush to clean the affected area and rinse with fresh water.

Two precautions here: 1) Add the acid to the water. Don’t add the water to the acid, a violent reaction may occur. 2) When working with muriatic acid it is an absolute must to wear eye, hand and body protection and to insure that vapors are not inhaled.

The subject of removing paint from a masonry surface approaches being book-worthy in complexity. Commonly used methods are endless. Sandblasting, wash-away or peel-off paint removers, hand or electric wire brushing, muriatic acid washing and power washing are a few. Surprisingly, as caustic as it is, muriatic acid doesn’t do well with paint. Sandblasting or wire brushing is hard, messy work, and paint removers sometimes create more mess than they eliminate. That’s why we recommend power washing. A commercial power washer can be rented for about $50 per day, it’s easy to operate, mess is kept to a minimum and you don’t have to be a chemist to make it work.

Is there a brick-cleaning day in your future? If so, try one of the methods we’ve mentioned. The end result will be a brighter, cleaner finished product with less elbow grease expended. If your masonry needs more than just cleaning, a masonry contractor can provide professional masonry repair services.

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