Concrete sealers are generally applied to the concrete surface to maintain it from wear that is caused by moisture, corrosion and staining. 

Concrete being porous can allow absorption of water and soluble contaminants like chlorides. This is why sealers are applied on concrete surfaces to work as repellents and protect from environmental factors.

There are three different types of sealers with distinctive applications. 

• Topical sealers are normally placed on the surface of the concrete to form a protective layer.

• Penetrating sealers. They penetrate the concrete surface and create a chemical boundary that protects against moisture.

• Integral sealers. They are normally added to the concrete mix before leaving the factory. 

Sealers come in different types but silicon-based ones are the most commonly used. The other types include;

• Linseed oil solution
• Epoxy
• Acrylic
• Polyurethane

Concrete inorganic elements react with sealers to fill the pores on the surface making it difficult for water to penetrate.  Sealers may not be able to stop pressure-driven water from permeating the concrete but absorbed water can vaporize because sealer materials are porous to water vapour. 

The concrete sealers can last for numerous years but this will depend on the concrete surface, repellent properties and the surrounding environment.

One of the characteristics of a sealer is a low viscosity material that is water or solvent-based.  They are applied using low-pressure spray to the surface of the concrete and penetrate through the pores for maximum protection.

The silicon-based compounds resist oxidation and can give good thermal stability which is heat resistant. Unlike the typical organic compound. They are known to be resistant to ultraviolet and water. This makes them adequate water repellent materials.

Another important characteristic of silicon-based compounds is that they are hydrophobic. They withstand water from the concrete surface which makes the droplets bead.

The following are some of the silicon-based sealers:

• Silanes
• Siloxanes 
• Silicates

Silanes and siloxanes have the strength to penetrate the concrete surface and fill the pores. Silicates react with calcium hydroxides that are found in the concrete and block the pores.  Some other silicate sealers are said to be identified as they harden the concrete surface. They are mostly used during the polishing of the concrete surface.

Other sealer products penetrate the concrete slightly, forming a thin film layer on the concrete surface. These products are based on organic resins like polyurethane, acrylics and epoxies. 

How to Select Concrete Sealers

The nature of the concrete and its roughness will determine the coverage rate of the sealer product to be selected. The amount of sealer product to be applied depends on the coverage rate of the same product. Normally you only need one or two coats but again this may depend on the concrete surface. The usage of the second coat is usually less than the first coat. Sealers are durable from one to several years. Linseed oil sealer has a short life span as compared to silane and siloxane.  The acrylic sealers have a coverage rate of 150-250 with the application of one or two coats.

The epoxy sealers have a coverage of 200-300 for the first coat and 400-500 for the second coat. Linseed oil sealers have coverage of 300-400 with an application of two coats. Polyurethane sealers have coverage of 250-350 with the application of one or two coats. Silane sealers have coverage of 250-400 with the application of one or two coats.

Siloxane sealer has coverage of 100-250 with the application of one or two coats. Silicate sealers have coverage of 400-600 for the first coat and 600-800 for the second coat with the application of one or two coats. Sealers should be applied occasionally, relying on the environment and service of the surroundings.