Concrete Sealing – A Definitive Guide

Concrete sealing is a very popular method to protect the concrete from any damage, corrosion or staining. Concrete sealer is applied on the concrete which helps the concrete resist drastic weather changes, water, and other degrading salts. Concrete sealing is advised for all those exterior concretes which are exposed to freeze-thaw cycles. Sometimes, concrete sealing is preferred for a particular purpose like dust repellent, stain repellent, chemical and abrasion resistance and so on. The sealer helps in bringing out the natural effect of concrete, and makes it easier to clean and maintain. Concrete sealing is a tricky task and work effectively, it has to be applied properly or else the porous concrete may absorb liquids, chemicals or stains. Also in a freezing environment if the concrete is not sealed, the absorbed liquid may expand, thus destroy the unsealed concrete.

Concrete sealing can be done via topical sealers which act like a top coat on the concrete and helps in protecting the concrete from above the surface. Being applied just on the surface, it has no reaction with the inner concrete and that’s why needs a clean surface to form a protective cover on the surface. Since it is applied on the surface only, it may change the texture, color or reflection of the concrete and may also reduce the friction of the surface (that is, become slippery when wet). Concrete sealing by topical sealers can last up to 5 years, however high-quality epoxy/urethane may help it last even longer.

Concrete sealing can be done by penetrating sealers. These sealers penetrate deep into the surface and react chemically with the concrete, thus creating a new solid chemical that acts like a barrier right beneath the surface. They can be applied on moist and damp surfaces as they block the moisture from being absorbed by the porous concrete. Penetrating sealers last longer than topical sealers as they go into the depths of the concrete and affect the chemical proportion of the sealer however; topical sealers just act like a top coat. Also, they do not affect the texture or appearance of the concrete and that’s why, are more preferable.

The surfaces are prepared before applying the concrete sealer so that different types of oil, grease, stains, dirt and dust can be avoided. This is important as it helps the sealer to stick to the surface properly while concrete sealing. Before applying any type or any branded sealer, it is advised to clean away all the other sealer applied previously to the concrete surface because the products may not be suitable to one another. This is recommended for best adhesion.

The usage of right tool is significant while concrete sealing so as to ensure proper coverage of the sealer and optimum thickness. The two very common methods in which the sealer can be applied are either by roller or by sprayer. Any two of the methods are preferable depending on the sealer’s solvency. A few important things to remember while applying the sealer are to ensure maximum coverage irrespective of the method used to apply; and the less one applies, the better result one gets. Before applying the second, it is recommended to apply it at least 3-4 hours after application of the first coat. Also, manufacturers suggest applying the second coat in the opposite direction to ensure proper coverage.

After concrete sealing, it is suggested to leave completely untouched for at least 28 days. After the sealer is applied, it should be left under 50°F above temperature for the best results.