Concreate, Inc. delivers concrete polishing and custom staining for both commercial and residential projects primarily in Virginia and Maryland (but also up and down the East Coast). We work hand in hand with with designers, architects, project managers, general contractors, tradesmen, and home owners alike from start to finish. We welcome the opportunity to serve your polished concrete needs in every way possible.

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Why Bother Grouting a Polished Concrete Floor?

Why Bother Grouting a Polished Concrete Floor?

A Concreate worker polishing a concrete floor.

While grouting a polished concrete floor isn’t usually necessary, it helps fill pinholes and creates a uniform appearance of the floor.

Key Takeaways:

  • Grouting usually isn’t necessary for a polished concrete floor
  • The exception is the presence of pinholes
  • Pinholes are less than 2 mm in size and can be filled using grout to create a uniform look
  • The result is a floor that has the same glossiness throughout

You’ve invested a lot of effort and time into polishing a concrete floor, from adding a concrete densifier, sealing the surface, and grinding it several times, to going over it multiple times with polishing pads. No doubt you want the surface to last as long as possible while retaining its glossy appearance.

To perfect the work, you may be considering taking your great job a step further with grouting. 

Perhaps you’re wondering if grouting should be applied on every polished concrete floor.

Well, the simple answer is “No.” 

Contrary to popular belief, you don’t need to add grout coats on every polished concrete floor. There are some reasons it’s a good idea to apply a grout coating to your polished concrete, however, and this guide will discuss some of those reasons. 

But before we get to that, let’s understand grouting.

What does grouting mean?

Grout is a material made from a mixture of sand, cement, and water or a combination of chemicals that are used to fill gaps. The compound is used to fill air holes while laying or repairing a concrete floor.

Grout materials are commonly used to strengthen structures during construction. The material is applied in pile foundations, under reaming, ground anchors, road construction, and dam construction, among other uses. 

Grout is also used to prevent water from seeping into the roof and walls of a building, as well as to fix tiles on the floor. 

The process of applying grout material in various construction works is called grouting

Grouting allows you to fill in pinholes on the surface so that the entire surface is uniform and refined. The process helps fix voids that are 2 mm or less. Larger cracks should be treated by patching them. A well-grouted surface has the texture of glass and is visually appealing. 

Grout can be cementitious or epoxy.

Cementitious vs. epoxy grout for concrete

Concrete works require specific types of grout capable of holding heavy loads to create a strong, appealing bond. Cementitious and epoxy grouts are the primary types you’ll see primarily applied in construction.

Cementitious grout uses cement as the binder and is sold as a powder. To make the grout, add water to the powder and mix the components. Cement-based grout is often used in homes. It’s not waterproof, however, and is therefore not the best material for grouting, depending on the area. 

Unlike cement-based grout that contains one component (powder) until mixed, epoxy grout is made by combining several components, including resin, a hardener, and a filler powder. 

Epoxy grout has become more popular among contractors thanks to its numerous benefits over cementitious grout. 

Benefits of epoxy grout

According to Data Bridge Market Research (DBMR) report, “the epoxy grout market is expected to witness market growth at a rate of 7.2% in the forecast period of 2021 to 2028 and is expected to reach USD 990.0 million by 2028.” 

Here are some of the reasons epoxy grout is becoming more popular:

  • Resinous compound: Because epoxy is made of chemical resins, it is a nonporous compound that doesn’t need to be sealed after. Even when mixed with sand to lend bulk, the resin will act like plastic.
  • Waterproof: Normal cementitious grouts aren’t waterproof. They absorb water when saturated, so they stain easily when in contact with colored liquids such as wine and fruit juice. The impermeable nature of resinous plastic, on the other hand, means the epoxy is waterproof and highly resistant to staining.
  • Easy to clean and maintain: Like most plastic surfaces, the resinous epoxy surface is very easy to clean. The fuss-free cleaning of the surface makes it possible to get rid of grime and the most stubborn dirt with just a wet wipe. 
  • Wide range of colors: Epoxy grout is available in a wide range of colors, with over 25 standard colors to select from. Matching the grout to the color of your surface is no longer as difficult as it once was. Some brands even offer impressive options like silver and gold sparkle to add a unique touch to your polished concrete while still giving superior protection and strength.
  • Thin and lightweight: Unsanded epoxy grout will more readily fill the substrate and could well be the only material you need to use if the concrete joints are very narrow. 

What is the purpose of grouting?

While polishing ground concrete with finer pads smoothens away most scratches, there are still going to be micro pits and pinholes left. 

While pinholes have no short-term effects on the structural soundness of the concrete floor, the nearly invisible pinholes not only reduce the clarity and radiance of the polish but may also lead to more serious gouges and cracks over time. 

Applying a grout coating on polished concrete helps reduce the effects of these imperfections. Grout pushes out air from the air holes and fills them. The process is essential for creating a seamless surface appearance while protecting the substrate. 

Grouting prevents air and moisture from seeping into the concrete substrate, helps level the floor, and keeps the surface from cracking.

Grout for polished concrete

Grouting of polished concrete helps fill pinholes, waterproof the surface, enhance the physical appearance of the surface, strengthen the slab, prevent seepage, and reduce surface subsidence.

It’s a significant construction practice that helps enhance the strength and appearance of floors and walls in industrial and residential buildings, food processing plants, restaurants, schools, hospitals, chemical laboratories, and more.

Polishing a concrete floor comes with a few challenges that are manageable with the right approach. Whether for residential or commercial places, grinding the floor exposes it to air holes and other types of flaws such as cracks and gouges. 

While grouting a polished concrete floor isn’t usually necessary, the process helps fill pinholes and create a uniform, shiny floor appearance. Filling these holes with epoxy grouting adds clarity to the floor and ensures everything looks the same. The result is a floor that has the same glossiness throughout.

Work with the industry experts at Concreate

At Concreate, we pride ourselves as industry experts. Our team has decades of concrete work experience, including surface prep, grinding, polishing, staining, joint work, and resinous floors. Do you need expert concrete services? Contact us today, and we’ll be happy to help.