Why Concrete Sealer? (5 simple reasons)

This article will answer the question “Why concrete sealer?” by discussing the importance of sealing agents in prolonging the functional life of your concrete.  Questions about the different types of sealants as well as their advantages over the other will also be covered on this blog post.

Why concrete sealer?

You need to apply a sealer on the surface of your concrete structure to protect it against unwanted moisture and soluble salt penetration. The porous property of concrete makes it highly vulnerable from this kind of event especially when it is frequently exposed to a damp environment.

The US National Ready Mix Concrete Association (NRMCA) verifies that one of the most common causes of concrete damage is the transfer of moisture through concrete pores. Other reasons include chemical intrusion, steel reinforcement corrosion, and reactions between alkali and silica compounds.

 Categories of Sealers

There are various kinds of sealants that can be used depending on the purpose. However, all of these can be categorized into two types, solely based on its ability to sift through concrete pores. The two main categories are topical sealers and penetrating sealers.

Topical Sealers

 Topical sealers are formulated in a way that its molecules are not capable in penetrating the pores of the concrete. They are also called as surface coatings or coatings for its mechanism of protection i.e. through physical binding of sealer molecules on the surface of the material. This is called adhesion.

In chemistry, adhesion is defined as the ability of different types of substances to adhere to one another due to innate adhesive forces between them. The opposite of adhesion is cohesion which is the attraction between similar substances.

Aside from a protective barrier against unwanted molecules and stains, topical sealers are also used for aesthetic purposes as they are known to visually enhance the overall look of the concrete structure. It offers slick, smooth, and glossy surface texture that’s why it’s also a common concern that topically sealed concretes are slippery. As a solution, you may opt to apply additives that have anti-skid property or feature to achieve the right texture of your desire.

On the average, topical sealers last for up to five years before recoating although other formulas could last way longer than that.

Penetrating Sealers

Unlike topical sealers, penetrating sealers are concrete protective agents that pass through its pores to initiate protection. The nature of its mechanism is a chemical reaction which means that upon entry to the matrix, penetrating sealers react with the materials inside to form a chemical protective barrier beneath the surface, thereby denying entry to unwanted moisture and destructive chemical agents.

In addition, penetrating sealers are also capable for wet or damp application unlike topical sealers. It is also important to note that the porosity property of the substrate should be known beforehand to expect optimal performance of this type of sealer. If the pores of the concrete is small enough for the entry of the chosen penetrating sealer, chances are the protective chemical barrier will not form as the chemical molecules would fail to react with substrate’s active ingredients.

If the aesthetics of your concrete structure is your top priority, you may prefer a topical sealer to penetrating sealer. Penetrating sealing agents are not able to induce the best glossy effect onto your surface, in fact the applied sealer is invisible to some extent.

Penetrating sealers also offer wide range protection against different substances as well as adequate shield against unfavorable harsh conditions. These properties of penetrating sealers qualify its use for outdoor purposes. Some of the widely known penetrating sealers are silanes, siloxanes, silicates and siliconates which normally last from five years or more.

Common Sealers

 There are a lot of sealing agents available in the market, so it’s great to have a reference for a list of sealers that are commonly utilized by a lot of users. These sealers are epoxy, acrylic, silicates, and silane. 

Epoxy Sealers

Epoxy sealers is a type of topical sealer that produces a durable, abrasion-resistant barrier against foreign agents such as stain, water, and soluble salt solutions. This kind of sealer often leaves a slick glossy finish, although this detail can be tweaked based on the preference of the user. In fact, it can either be transparent or translucent depending on the color pigment added on the formula.

When epoxy sealers are applied, they form physical bonds on the surface of the concrete that is too dense and strong, the moisture trapped within could no longer escape. Hence, it is crucial to make sure that the concrete surface is dry and free of other contaminants prior to application.

Because epoxy sealers offer robust protection against moisture and destructive chemicals, it is often applied as a sealing agent in concrete countertops where most activities require water. In addition, epoxy is also utilized as coating in cement-based overlays and floors that are high-traffic such as in grocery stores, restaurants, and public comfort rooms.

If you need epoxy sealers for your countertops and you’re thinking of a formula that is durable, UV resistant, self leveling, and glossy; you may check out this recommendation at this link

Acrylic Sealers

Like epoxy, acrylic sealer is a type of topical sealer which means that in the molecular level, adhesive forces act upon the surface of the concrete to introduce protective coating. Water-based and solvent-based acrylic sealers are available in the market at a highly affordable price. This makes acrylics as one of the top choices of consumers when looking for ways to protect and beautify their concrete structures. Aside from water repellency, they are also resistant to UV radiation and yellowing or discoloration; hence, acrylic sealers are applicable to both interior and exterior environments.

One of the advantages of using acrylic sealers is its ability to dry within a short period of time (typically after an hour), that’s why it is highly recommended to use this type of sealer when the project needs to be done immediately. Furthermore, acrylics offer a wide range of protection against moisture as well as chemicals that include chloride. Most often than not, you may have seen acrylic sealers at your home, as it is often used to preserve interior surfaces or to improve their appearances.

Silicate Sealers

Silicate sealers belong to the category of penetrating sealing agents which allow chemical reaction with the substrate to create a protective barrier against water molecules. When silicate sealers enter the pores of the concrete, silicate binds with the calcium present in the matrix forming a calcium silicate hydrate structure or CSH.

This type of compound increases the internal density of the structure as well as reduces the porosity of the concrete, thereby decreasing the penetrability of the overall structure. It’s as if the sealer becomes part of the structure itself. It doesn’t only act as a surface cover for protection. Instead, it becomes associated with the concrete for long-lasting protection.

The two most common silicate sealers are sodium silicate and lithium silicate which both form a CSH structure. Lithium silicate offers more stability compared to conventional silicates resulting in a more uniform reaction beneath the concrete surface. Having an even and well-distributed reaction is important for optimal sealing and densification. Furthermore, lithium silicates do not absorb moisture unlike other silicate sealers. Water absorption isn’t desirable as this often causes alkali-silica reactions that result in integrity failure in the long run.

Because silicate sealers are both hydrophobic and oleophobic, the most probable reason for it to wear off is the presence of physical damages on the concrete surface itself. Other than that, silicate sealers could deliver the following advantages for your benefit:

·  No color change on concrete for those who want the concrete to look the same even after sealer application

·  Reduction in dust present in the concrete surface, as the overall structure will show increased durability and protection from wearing off

·  Reduction or even elimination of water penetration into the pores of the of the concrete

Silane Sealers

Silane belongs to the family of silicone and is considered as one of the sealing agents with the smallest molecular size. This property allows the material to penetrate concrete pores easily and quite deeply, thereby resulting in a more in-depth chemical barrier against water and chemical molecules. Because of its ability to reach deeper lengths of the matrix, silane-sealed concrete is known to have excellent resistance against abrasion and weathering. As a trade-off of this property, it is also known for silane to have high volatility, therefore it requires more product than its less volatile counterparts.


This article answered the question “Why concrete sealer?” It was clearly pointed out that sealers protect concrete from water and chemical penetration which could lead to decrease in structural strength and integrity in the long run. The blog post also discussed the two categories of sealers such as topical and penetrating sealing agents. Finally, the four common concrete sealers in the market are also tackled in this article, giving brief guidance to those planning to seal off their concrete structures soon.

For any questions and suggestions about this article, please feel free to submit your thoughts in the comment section below.

Frequently Asked Questions (FAQs): Why concrete sealer?

What is the purpose of a concrete sealer?

The main purpose of concrete sealer is to repel water and other soluble components from entering the concrete matrix. Reduced water penetration is important to preserve the integrity of the structure, leading to longer functional life. For this reason, it is greatly recommended to install sealers when your concrete structure is often exposed to moisture.

Is sealing concrete necessary?

Yes, sealing concrete is necessary if you want to have your concrete structure to last longer. Although, it is important to note that concrete can stand alone without it. It is durable enough with or without sealants, but the effect of a quality sealant could definitely make a difference in the overall quality of your structure. You could try to work on applying sealers onto the surface of your concrete all by yourself since it is a straightforward process.

Does sealing concrete make it easier to clean?

Yes, sealers or sealing agents allow effortless cleaning of your whole concrete structure. Dirt from cooking such as oil, grease, and other spices are definitely easier to remove when your concrete countertops are equipped with sealants. Also, it protects concrete from unwanted penetration of water and other soluble elements that could affect the integrity of the matrix.

Is concrete sealer slippery?

Yes, concrete sealing agents are slippery yet manageable. Although it is important to note that sealing agents are beneficial to your concrete structure as it protects it from unwanted penetration of water and other compounds. Hence, it is recommended to use sealer when your concrete is always exposed to moisture.

What is the best type of concrete sealer?

The best type of sealer in terms of durability is epoxy sealing agents. They are strong and long-lasting, so they are recommended for usage in garage floors and grocery stores that have high-volume customers. In terms of affordability, the softer acrylic sealing agents are recommended. They are more appropriate for usage in concrete floors of households.

Is it better to spray or roll concrete sealer?

Spraying or rolling concrete sealing agents actually depends on the formulation of the sealant, specifically the solvent present in the product. For those with highly volatile solvents, it is recommended to spray the material. In contrast, those sealing agents that only slowly vaporize are good for rolling.


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Sealers Shown to Lengthen the Service Life of Concrete Bridges Exposed to Chloride (October 1997) Road Manag J 2. www.usroads.com/journals/p/rmj/9710/rm971002.htm. Accessed 13 Sep 2004

Tabatabai, H., Pritzl, M. D. & Ghorbanpoor, A. (2009). Evaluation of select methods of corrosion prevention, corrosion control, and repair in reinforced concrete bridges (p. 343). Madison, WI: Wisconsin Highway Research Program, Report No. WHRP 09-04.