Guide in concrete staining

To enhance the beauty of your concrete floor, your best option is concrete staining. This enhancement process does more than simply add color but it creates an opaque solid result similar to paint or colored coatings. The stains penetrate the concrete and fill it with abundant, intense and semi-opaque tones.

Two types of concrete stains are the reactive and the nonreactive. The reactive type is an acidic solution that is water based with metallic salts that respond with the lime content of the concrete. Once reaction of chemical is underway, the stain forges a lasting bond with the concrete and would not peel away or chip off.

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The non-reactive stains are acrylic water-based stains that do not depend on the reaction of the chemical to provide color. They are created to filter inside the concrete material and deposit their pigmented particles in the open pores. Over the past years, this type of stain has achieved popularity for they offer a wider palette of colors than the concrete type and are easier to apply. The con: non-reactive stain does not result in the same varied and semi translucent tones characterizing acid stains. The color effects tend to be cloudier and more uniform.

Concrete stains are affected by the following factors: (1) acid in chemical stains allowing metallic salts to reach the free lime deposits; (2) cement properties and its amount; (3) admixtures used; (3) type of aggregate used; (4) concrete finishing methods; (5) concrete age and moisture content when stain is applied; (6) weather conditions when stain is applied; and (7) efflorescence.

In general, during hydration, more stain and intense colors will come out on cements as a result of the large amounts of calcium hydroxide produced. The presence of Ca2 accelerators cause mottled, darkened areas so highly recommended are nonchloride accelerators.

Most contractors are using hard-troweled staining surfaces because they make colors last longer and look richer. To insure enough penetration of the stains, use a higher acid concentration or grind the surface.          .

Slabs set during wet weather have richer stain color as wet slabs are prone to more effloresce, lightening of color and a more speckled look in places where the sprouting salts prevented deeper absorption. When the sun is hot, concrete becomes become dry, and the stains are unable to penetrate deeply into the concrete.

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However, continuous exposure to water causes gradual reaction for the concrete to turn brown or even black. At the start, it presents an interesting variation of the colors – the all blue-green color changing to brown and black. Due to the possible shifting of colors, manufacturers advise users not to use these colors for exterior concrete. These interior slabs have to be set-up on a well-drained base or sub-grade and on low moisture content before applying the stain. They surmised that the changing colors of blue-green stains to brown-black are caused by oxidation of a copper component resulting from water vapor passing through the slab. Others opined that the brown color is caused by a fungus, which can be rectified by using sealers containing a fungicide.

Concrete staining is one way to beautify your home; giving an ambiance of sophistication and class. However, the best way is to hire a professional for a well-done job!