With dozens of types of concrete sealers and hundreds of brands on the market, it may be a daunting task to choose one to purchase and apply for a DIY project.
Before selecting a sealer, it’s important to understand the various purposes and uses of the main types and to have a good understanding of what qualities you’re looking for regarding protecting your surface and the appearance you want it to have.
Silicone, silanes, and silicate sealers all fall under the penetrating sealers category and serve various purposes. Penetrating sealers are used on a variety of bare concrete surfaces to protect the concrete from erosion, staining and natural forces such as UV rays, extreme temperatures, and weather.
Silicate concrete sealers are a good choice as a densifier and hardener of concrete surfaces. However, they will offer no protection from water damage. This type of sealer does not alter the natural appearance of concrete surfaces once applied. Silicone and silane penetrating sealers both provide water protection, but each has their drawbacks.
Silicone concrete sealers are a penetrating sealer used best as a short-term sealant to protect surfaces you anticipate having to resurface regularly. For example, apply a silicone sealer to concrete walls that may be subject to graffiti or on vertical concrete surfaces that need frequent cleaning or power washing.
Silicone sealers are not a good choice for horizontal surfaces or surfaces requiring UV protection. If preserving the physical appearance of the concrete itself is important, silicone sealers are an excellent choice because they penetrate deeply into the pores of the concrete and do not usually change its appearance.
Unlike silicone sealers, silane sealers may slightly alter the appearance of the concrete by darkening it because this penetrating sealer requires a thick application as well as 2-3 coatings. However, doing so can yield up to eight years of protection. Silane sealers are typically used on concrete block and brick structures such as parking garages and exterior walls.
Epoxy sealers are a popular choice for design purposes because it is easy to add color pigmentation and leaves a glossy surface on interior concrete. Additionally, an anti-slip aggregate can be added to epoxy sealers making them an excellent choice for garage floors or industrial surfaces where water may sometimes pose a safety threat.
They are best used indoors, however, as UV rays stain epoxy surfaces over time. Once cured, an epoxy seal also does not allow the concrete surface beneath it to breath in the same way that penetrating sealers and acrylic sealers do.
Like epoxy sealers, acrylic sealers add a glossy surface to concrete. This type of sealer is used both indoor and outdoor. Unless you select an acrylic sealer with non-yellowing additive, however, it will likely yellow over time and often delaminates, causing visible damage to the smooth surface of the sealed concrete. Some acrylic sealers are UV resistant.
Polyurethane sealers work well on both indoor and outdoor to protect horizontal surfaces concrete in high-traffic areas or high use areas like floors and countertops. The finish of polyurethane varies from a slight sheen to a high gloss and helps prevent staining and scuffing.
Polyurethane sealers do not modify the color of a surface and do not yellow over time. This type of sealer is an ideal choice for garage floors as it is abrasion resistant and offers flexibility to withstand impacts that brittle acrylic seals do not.
However, at least two coats will be necessary while some epoxy sealers are one-coat capable. Additionally, polyurethane sealers have high levels of VOC (volatile organic compounds), and a respirator is recommended for application.