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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3 Ways to Grout a Polished Concrete Floor

3 Ways to Grout a Polished Concrete Floor

A concrete contractor mixing grout to apply on polished concrete.

Are you looking for the best way to grout your polished concrete floor? Check out these three methods and find the one right for you.

Key Takeaways:

  • Good grouting can be a quick and cost-effective way to achieve good visual results
  • Bad grouting not only looks terrible but can also cause damage to polished concrete floors
  • Grouting polished concrete floors can be done with either epoxy grout or cementitious grout
  • Sanded and unsanded grouts have different uses and effects
  • The nature of the joint can dictate which grouting method is required
  • Professional consultation can help you choose the right grouting method

Polished concrete floors add an elegant, high-end look to any space. Its polished finish provides a smooth, level surface that is durable, low maintenance, and slip-resistant. However, polished concrete is only complete with grout. So, what is the purpose of grouting?

Grouting polished concrete floors help to create a seamless finish, filling any joints or cracks that may have developed during installation. It also adds texture, depth, and style to polished concrete floors. Improper grouting exposes your polished concrete to potential staining, discoloration, and cracking. Water, dirt, and other contaminants can also penetrate the polished concrete, reducing its aesthetic appeal and leading to costly repairs.

Knowing the right way to grout polished concrete is essential. When done correctly, it can improve the look and longevity of your floors. You can choose from various grout colors, finishes, and textures to customize your polished concrete floor to perfectly complement your décor. Read on for 3 ways to grout polished concrete floors.

How does grout work?

Grout is a binding material used to fill the joints between polished concrete floor slabs. It is typically a combination of Portland cement, sand, and other aggregates that give grout its strength and durability. Grout also helps to prevent water from seeping between polished concrete slabs, reducing the risk of mold, mildew, and staining. When grout dries, it forms a strong bond between polished concrete slabs, creating a seamless, level surface.

Top 3 effective ways to grout polished concrete

Proper grouting is essential to maintain your polished concrete floor’s aesthetic appeal and longevity. Use these 3 effective ways to grout your polished concrete floors:

1. Pre-mixed grout

Pre-mixed grout is the most common choice for polished concrete floors. It’s a ready-to-use product composed of a mix of Portland cement, sand, and other aggregates that can be easily applied with a rubber float or trowel. 

Pre-mixed grout is available in several colors and textures, making it easy to customize your polished concrete floor’s look. You don’t have to worry about mixing your grout and getting the ratios right. 

To apply pre-mixed grout:

  1. Pop open the container, scoop out the grout, and spread it evenly with a rubber float or trowel.
  2. Wipe away any excess grout with a damp sponge.
  3. Allow the grout to set according to the manufacturer’s instructions.

Look for pre-mixed grout with urethane or latex to improve adhesion and flexibility. Choose a color that matches the polished concrete and complements your décor.

2. Epoxy grout

Epoxy grout is a two-part system composed of resin and hardener that create a durable, waterproof bond. It’s a great choice for polished concrete floors in high-traffic areas because it’s highly resistant to staining, cracking, and chipping. 

While it has excellent chemical resistance, epoxy grout has a low coefficient of thermal expansion, requiring installation temperatures of over 32°F. It’s also challenging to work with since it sets quickly and requires up to 72 hours to cure. Before you apply the epoxy grout, clean the polished concrete floor, removing dirt, debris, or oils. These can interfere with the grout’s adhesion and cause it to fail.

To apply epoxy grout:

  1. Mix equal parts of resin and hardener according to the manufacturer’s instructions in a bucket or container, stirring until you achieve a consistent, lump-free mixture.
  2. Spread the epoxy grout evenly over polished concrete slabs using a rubber float or trowel. Apply pressure to ensure the grout penetrates the joints sufficiently and wipe away any excess grout with a damp sponge.
  3. Allow the epoxy grout to set and cure according to the manufacturer’s instructions before using your polished concrete floors.

For proper application, hold the trowel at a 45-degree angle and apply a generous amount of grout to avoid gaps and voids that can trap dirt and debris. 

3. Cementitious grout

Cementitious grout is a blend of Portland cement, sand, and water that provides good adhesion and flexibility. It’s cost-effective and easy to work with but less durable and resistant to staining and chipping than epoxy grout. There are three types of cementitious grout:

  • Sanded: Contains fine sand particles, which increases strength and provides a better grip on polished concrete slabs. It is suitable for concrete floors with 1/16–1/8-inch joints.
  • Unsanded: The lack of sand particles gives it a smooth texture, making it ideal for polished concrete floors with 1/8–1/4-inch joints. It can crack or shrink when used in wider joints.
  • Polymer-modified: Contains polymers like latex that increase adhesion and flexibility, making it the best choice for polished concrete floors with up to 1 1/4-inch joints. It is also more resistant to water and heat than standard cementitious grout.

To apply cementitious grout:

  1. Mix the cementitious grout powder with water according to the manufacturer’s instructions in a bucket or container to form a thick paste.
  2. Spread the grout over polished concrete slabs with a rubber float or trowel, pressing gently to ensure it penetrates the joints.
  3. Using a damp sponge or cloth, wipe away any excess grout in a circular motion.
  4. Allow the grout to set and cure according to the manufacturer’s instructions before using polished concrete floors.

Cementitious grout takes 24–72 hours to completely cure, depending on the ambient temperature and humidity. However, allowing an extra day or two before walking on the polished concrete floors is good.

The method you choose to grout polished concrete floors will depend on the size of the joints, your budget, and the environment of the polished concrete floors. The key to successful grouting is to ensure that all steps are followed correctly, from cleaning the polished concrete floors to allowing the grout to set and cure. Hiring an expert concrete contractor will help ensure professional, quality results. 

Let Concreate help grout your polished concrete floors

For over a decade, Concreate has been the go-to concrete contractor in Virginia and Maryland. We specialize in polished concrete floors and can provide expert installation, maintenance, and repair services. Our top-quality materials, superior technique, and prompt service make us the best choice for polished concrete floor grouting. 

We also offer professional consultation and advice on polished concrete floor grouting, helping you choose the best method for your project. Get in touch with us today for a free estimate, or browse our website, thisisconcrete.com, for more information about our concrete services.