Almost every type of concrete finish requires the application of a concrete sealer either as a protective coating for an existing concrete surface or as a curing agent for new ones. The application of a sealer is done ideally as soon as the fresh concrete is installed in order to lock in moisture and so prevent the surface from curing or drying too quickly. Otherwise, the concrete's surface will not bond well with the rest of it, which creates a greater risk of scaling later on.
Different Types of Concrete Sealer and When to Use Them
What are the types of concrete sealers?
Basically, concrete sealers fall into two main types:
- Surface sealers - these are the most popular types of sealers and works by creating a protective coating over the concrete's surface to keep water, stains, chemicals and other foreign elements from entering the concrete. They also typically add sheen to the surface, highlighting decorative concrete finishes.
Under this category are three types of sealers:
1. Acrylic Sealers - Although it is softer compared to other types of surface sealers, acrylics are the most ideal for exterior use because they are UV-resistant and does not retain moisture. They greatly improve the look of decorative and colored concrete finishes by creating a wet glossy appearance.
2. Epoxy sealers - Like acrylics, epoxies create a polished concrete surface but they offer more strength than acrylic sealers. However, they trap moisture in the concrete so they are not suitable for outside applications and are recommended for interior use such as garages. One disadvantage of using epoxies is you need to do more in terms of prepping the surface before you can apply it and it is usually more expensive than acrylics.
3. Urethane sealers - Urethanes or polyurethanes is about double the thickness of acrylics, which makes it highly resistant to abrasion and chemicals. Indeed, urethanes are the strongest types of sealer but they are also the most expensive and, therefore, typically used for industrial applications. Their application is also best left to concrete professionals.
- Penetrating sealers or 'penetrants' - As its name suggests, this type of sealer penetrates or seeps below the surface. They are usually made with silicone and produce a chemical reaction within the concrete's capillaries, strengthening the concrete and making it tightly packed to keep water out.
Their major difference with surface sealers is they do not create an obvious change to the appearance of the concrete's surface so they are mainly used not for aesthetic purposes but to make exterior concrete more durable against corrosion and the damage that can result from freeze-thaw weather cycles.