What Grout Should I Use Outdoors?

What Grout Should I Use Outdoors?

What Grout Should I Use Outdoors is a fairly typical question that must be answered by homeowners, architects, designers, and contractors alike.Let’s start with understanding what grout is and what unique challenges are posed by the outdoor environment.

What is Grout?

Before any further discussion, it is a good idea to understand a bit more about the nature of the material. Typical grout is a mixture of cement, sand, and water used to fill the spaces between tiles, usually in bathrooms, kitchens, and other tiled surfaces. It helps secure the tiles in place and prevents water from seeping through.

There are a variety of challenges that grout faces when used outside vs when it is used inside. Here are a few of them:

1. Freeze-thaw Activity

“Freeze-thaw”  refers to the process where water freezes into ice and then thaws back into water. This cycle can occur repeatedly, especially in regions with fluctuating temperatures, and it can have significant effects on various materials, such as rocks, soil, pavement, built structures, tile, and stone.  The expansion of water as it freezes can cause mechanical stress and deterioration in these materials over time.

Since non-epoxy grout behaves much like concrete, it is susceptible to freeze-thaw damage due to its porous nature. When water enters its pores and then freezes, it may expand,  exerting pressure on the surrounding matrix. This expansion can lead to cracking, spalling (flaking or popping off of surface layers), and deterioration of the grout over time. Additionally, repeated cycles of freeze-thaw can exacerbate the damage, compromising the structural integrity and longevity of the entire tile and/stone installation.

Epoxy grout will mitigate the risk of freeze-thaw damage by minimizing water infiltration into the entirety of the installation system. A solid point for epoxy type grout.

2. Staining

Regular grout can stain due to its porous nature, which makes it susceptible to absorbing liquids and particles. Common causes of grout staining include spills of liquids like coffee, wine, or oil, as well as dirt, grease, and soap scum buildup. When these substances penetrate the grout’s surface, they can leave behind discoloration and stains. Additionally, improper sealing or lack of sealing can make grout more vulnerable to staining. Regular cleaning and sealing of grout can help prevent and minimize staining, preserving its appearance and integrity.

Epoxy grouts, such as our best-in-class Starlike Evo, is harder, denser, and infinitely more capable of resisting aggressive exterior staining agents than mere cementitious grouts. This is fundamental to answering What Grout Should I Use Outdoors?

3. Crack Suppression

Epoxy grout offers greater crack suppression in the overall construction environment. Not only does it provide superior strength and durability, as previously  discussed, it will also provide a level of flexibility that cementitious grout has trouble attaining.


“What Grout Should I Use Outdoors?” should not be a daunting question in the grand scheme of things. Simply understand the technical performance requirements first. Then, move on from there. As always, thanks for reading.

Share This Story: