Penetrating Sealer vs Acrylic Sealer

This is a much debated topic in the concrete sealer industry and in an effort to better market their products, manufacturers have managed to confuse us all. While an acrylic sealer is called a sealer, it couldn’t be more different from a penetrating sealer. Penetrating sealers work below the surface and don’t leave behind a visible surface film or coating, and acrylic sealers bond to the surface and leave behind a visible surface film.

The two most common types of penetrating sealers are concrete densifiers and water repellent sealers. Concrete densifiers are used to increase the strength and density of the concrete, while water repellent sealers are used to reduce surface water absorption. Both types of penetrating sealers work entirely below the surface and will not change the look or color of the surface. The surface will look exactly as it did before being sealed. Sealers help to PREVENT a variety of issues:

  • Silicate Sealers: Silicate sealers increase the strength and density of the concrete in order to reduce concrete dusting and deterioration caused by surface abrasion. The two most common types of silicate sealers are sodium silicate sealers (used for porous concrete surfaces) and lithium silicate sealers (used for dense concrete surfaces).
  • Water Repellent Sealers: Water repellent sealers reduce surface water absorption through the pores, therefore reducing deterioration caused by water absorption such as cracking, spalling, pitting, mold an mildew growth, and efflorescence formation. The two most common types of water repellent sealers are Silane-Siloxane sealers (for all concrete and masonry surfaces) and Siliconate water repellent sealers (for white and light poured concrete surfaces).

Acrylic sealers are very different. Under the category of acrylic sealers there are water and solvent based acrylics, pure acrylic lacquers, acrylic co-polymers, and acrylic latex sealers. All acrylic sealers leave behind a visible surface film, usually in the form of a satin to low gloss, or a high gloss.  Acrylic sealers help to STOP damage caused to surfaces by leaving a protective surface film.

  • Pure Acrylic Lacquer Sealers: These are simply pure acrylic sealers. They offer an aggressive bond to the surface and leave behind a hardened, UV resistant surface film.
  • Acrylic Co-Polymer Sealers: These types of sealers are slightly more resistant to moisture which is why they are also the most common type of cure and seal. They cost less to manufacturer, but still leave behind a hardened, UV resistant surface film.
  • Acrylic Latex Sealers: Run. In short, run. Acrylic latex is pretty much a paint. They don’t really bond to the surface like acrylic lacquers and co-polymers. Instead, they “stick” to the surface. Acrylic latex sealers have issues with adhesion, and they are very hard to maintain. Most calls to any manufacturer are how to remove acrylic latex sealers. You really only find this type of product in big box stores (BEHR, Sherwin Williams).
  • Water Based Acrylic Sealers: Water based acrylic sealers aren’t bad, but they are harder to maintain. They aren’t self-priming so when it comes time to repair or re-coat a water based acrylic, often times parts of the acrylic need to be removed. For areas that aren’t in need of repair, screen sanding is often required to help the new coat bond to the surface. If you are considering a water based acrylic, take into consideration life and maintenance.
  • Solvent Based Acrylic Sealers: Solvent based acrylic sealers are the best type of acrylic sealer simply because they bond well and are very easy to maintain. Areas in need of repair can be repaired with Xylene, and when it comes time to re-coat you simply put more material down to a clean and dry surface.

Which sealer is better?

One penetrating sealer isn’t necessarily better than the next. You need to think about your reason for sealing, and what you want the surface to look like once sealed. In some cases you may find you want to combine sealers.

  • Silicate Sealers: Silicate sealers can only be applied to unsealed concrete. They can’t be applied to concrete previously sealed with a water repellent or acrylic sealer unless all of the old sealers have been removed from the surface and the pores. Once a surface has been sealed with a silicate sealer, water repellent sealers and acrylic sealers can be applied over them.
  • Water Repellent Sealers: Water repellent sealers can be applied over surfaces previously sealed with a silicate sealer but a silicate sealer can’t be applied over a water repellent sealer (the water repellent will cause the silicate to bead off the surface). Once a surface has been sealed with a water repellent sealer it can be coated with a solvent based acrylic sealer. Water based acrylic sealers will bead off the surface however so those can’t be used.
  • Acrylic Sealers: Silicate sealers and water repellent sealers can’t be applied over acrylic sealers, but acrylic sealers can be applied over surfaces sealed with a silicate sealer or a water repellent sealer. Only solvent based acrylic sealers can be applied over surface sealed with a water repellent sealer because water based acrylics will bead off the surface and won’t be able to bond.

The most popular combination of sealers is a silicate sealer and a water repellent sealer. Homeowners want both an increase in strength and water repellency which is why this combination of products is often used. Acrylic sealers are very rarely used in combination with penetrating sealers, unless a homeowner put down a sealer originally and then decided they would prefer a gloss. There are lots of scenarios that can lead up to combining products. If you have any questions, it is best to contact the manufacturer of the products you are considering and explain to them what you are trying to achieve.

 

Silicate Sealer Water Repellent Sealer Acrylic Sealer
Works below the surface Works below the surface Sits on the surface
Won’t change the look of the concrete Won’t change the look of the concrete Leaves behind a visible surface film
Matte Matte Low gloss and high gloss
Clear Clear Clear and color options
Lasts forever Lasts 7-10 years Lasts 1-4 years
Increases the strength of the concrete Reduces surface water absorption Enhances and protects surface