Penetrating garage floor sealers are sealers that penetrate into the garage floor and chemically react without changing the look or color of the garage floor. They are designed to protect the concrete without changing the look or color, and reduce issues such as cracking, spalling, pitting, staining, mold and mildew, and efflorescence.
The two best penetrating garage floor sealers are concrete densifiers and water repellent sealers. While both types of penetrating sealers fall under the same category, they couldn't be more different in terms of performance abilities.
Concrete Densifiers: Concrete densifiers chemically react to form calcium silicate hydrate (CSH) within the pores. CSH looks like tiny white crystals, and they continue to grow within the pores for up to 90 days after application. Concrete densifiers increase the density of the concrete, therefore increasing the strength. Concrete densifiers are used to strengthen weak concrete, reduce dusting and deterioration caused by surface abrasion, reduce efflorescense, and reduce sub-surface water seepage through the concrete.
Water Repellent Sealers: Water repellent sealers chemically react to form a hydrophobic (water repellent) barrier within the pores. Water repellent sealers help to reduce the absorption of surface water and other liquids, to reduce staining and deterioration, and mold and mildew growth.
The most common type of water repellent sealer is a Silane-Siloxane sealer. Siliconate sealers are fantastic water repellent sealers, but when used on dense concrete, like a garage floor, they will leave behind a semi-permanent white surface residue. Silane-Siloxane water repellents are the best penetrating water repellent sealer for dense concrete because they won't leave a surface residue, and they won't change the look or color of the concrete.
Which Penetrating Concrete Sealer is Best?
As mentioned before, one type of penetrating sealer isn't better than the other, but the best sealer for your garage floor will depend heavily on the condition of your concrete and your reason for sealing. If you have issues with dusting, weak concrete, efflorescence, or seepage, then you want a concrete densifier. If you have issues with staining and deterioration, moisture, mold or mildew, then you want a water repellent sealer. If you have weak concrete, and concrete with issues caused by water absorption, then you need both a densifier and a water repellent sealer. In this case, you would apply the densifier first, followed by the water repellent sealer a week later. While it never hurts to use a densifier, water repellent sealers are the best type of sealer for use on garage floors because it offers the most protection against water and other liquids spilled onto the surface.
Acrylic sealers are classified as sealers because they penetrate in order to bond, but they also leave behind a visible, protective surface film. Sealers are designed to reduce, and coatings are designed to stop. If you want total protection against staining and deterioration, or prefer a wet look, low gloss, high gloss, or colored finish, then you want an acrylic sealer. Acrylic sealers are just as easy to apply as densifiers and water repellent sealers, and will last for up to 4-6 years, sometimes longer, before the need to recoat.