What are efflorescence and how to remove them on brick and concrete?

In the spring, on many brick fences and houses, you can find this picture:

After contact of the masonry with melting snow, the so-called "efflorescence" appears. The brick itself does not emit them - these are calcium salts from concrete. In concrete, not all of the composition is hydrated and a lot of water-soluble calcium salts (lime) remain. And when the concrete gets wet, salts dissolved in water are released from it, washed out.

If this happens, then at least they can be washed off. It will not be possible to do this completely, and next spring this picture may be repeated.

There are products on sale for getting rid of efflorescence on brick and concrete. You can find it in any major hardware store. I will not tell you how each of them works. But there are those that are based on fluating principle. The fluorosilicates in the impregnation react with calcium salts to form strong water-insoluble calcium fluoride compounds. The connection also increases the strength of concrete by 20-30%. If the layer of impregnation with fluating impregnation is ~ 1 cm, the treatment will prevent the release of calcium salts to the surface.

I used impregnation MB-1 (second slide). Cost in 2019 was 320 rubles / liter. Diluted in 3 liters of water. Used not to remove efflorescence, but to increase the strength of concrete.

To completely prevent the appearance of efflorescence on concrete, you need to cover the concrete with any colorless alkyd impregnation for wood or varnish for stone. This will protect the concrete from absorbing water and washing out salts. Or there are so-called water repellents. But they are short-lived on the surface - the effect of water repulsion will last for several years.

The concrete part of the fence is covered with stone varnish. I did not take a spring photograph, but after the snow melted, I did not find any efflorescence.

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Photos are taken from open sources, from Yandex. Pictures

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