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Will Concrete Sealer Fill Hairline Cracks?

Concrete sealer is an incredibly useful chemical for the preservation and maintenance of your concrete surfaces around the exterior of your home. In this article, we will cover what concrete sealer is, why it cannot be used to fill hairline cracks in concrete, and what to do instead. 

What is a concrete sealer?

Concrete sealer is a protective coating applied to concrete surfaces to increase their durability and longevity. It is composed of various chemicals such as acrylics, epoxies, polyurethanes, or silicates. Concrete sealers serve multiple purposes in preserving and improving the appearance and performance of concrete structures.

The primary purpose of a concrete sealer is to create a barrier that prevents moisture, chemicals, oil, grease, and other contaminants from penetrating the concrete surface. By sealing the pores within the concrete, these sealers reduce or outright eliminate water intrusion, which can lead to cracking, spalling, and other forms of deterioration over time. Read more about the purpose of sealing your driveway here.

Concrete sealers also enhance the aesthetic appeal of concrete by intensifying its color, adding a glossy or matte finish, or providing a wet look. They also offer protection against UV radiation, which can cause fading and discoloration of concrete surfaces exposed to sunlight. Read more about concrete sealers with color.

Concrete sealers can improve the overall performance of concrete by facilitating easier cleaning and maintenance and reducing wear over time. They are commonly used on driveways, sidewalks, patios, garage floors, warehouse floors, and other concrete surfaces subjected to heavy foot traffic or vehicular movement.

Concrete sealer serves as a vital protective layer for concrete surfaces, guarding against damage from moisture, chemicals, UV rays, and wear and tear, while also enhancing their appearance and longevity.

Can concrete sealers fill hairline cracks?

Concrete sealers are not typically designed to fill hairline cracks. While some sealers may have limited filling capabilities for very fine cracks, they are not a substitute for proper concrete crack repair methods. Hairline cracks, which are very narrow and shallow, can be caused by shrinkage during curing, temperature changes, or minor settlement of the substrate.

It's crucial to address hairline cracks quickly, as they can worsen over time due to repeated exposure to environmental conditions and traffic loads. Failing to properly repair these cracks can lead to more significant structural issues and compromise the integrity of the concrete surface. Sealant can be useful in sealing the crack to prevent water intrusion, but it will not fix the crack.

How to fill hairline cracks in concrete

For effective repair of hairline cracks, specialized concrete crack fillers or sealants are recommended. These products are specifically formulated to penetrate into the narrow cracks, providing a strong bond and preventing further intrusion of water or contaminants (like oil). Depending on the severity of the cracks, different types of crack fillers may be used, such as epoxy injections, polyurethane sealants, or acrylic crack fillers. Many of these appear similar to caulk and are similarly simple to apply.

While concrete sealers offer excellent protection against moisture and other contaminants, they should be applied to a properly repaired and prepared surface to maximize their effectiveness. This includes filling any cracks or voids before sealing to ensure optimal performance and longevity of the concrete surface.

If you are a homeowner in the Midwest in search of a company that can properly seal your concrete, reach out to EcoWash today for a fair, reasonable, and customized quote.


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