Using Thinset as Grout – Building Contractor Speaks Out

When installing tiles in homes, thinset and grout are two substances that are very vital in the overall process – thinset is used to hold tiles to surfaces while grout is used to fill up gaps. If you are installing or repairing tiles in your home, you might be wondering if you can use thinset in place of grout.

Can you use thinset as grout? You should not use thinset as grout because it thinset does not flow easily the way grout does. If thinset is used as grout, there will be air pockets and gaps when it dries, affecting the integrity of the tiles.

Chris Deziel, who is a building contractor, mentioned that thinset is not an appropriate substitute for grout because thinset will leave gaps after drying. After a while, water might begin to seep into these gaps, and the tiles will be weakened. I recommend the Premium Grout that is available on Amazon. Click here to have yours delivered to your front door.

Is Grout the Same as Thinset?

Grout is not the same thing as thinset. People may mix them up, mistaking them for the same thing. Thinset is used to adhere tiles to a surface, whereas grout is used to fill in gaps between the tiles.

Grout and thinset are cement-based tiling materials commonly used in construction and home renovation projects. Even though they are both cement-based products, their properties and applications are quite different. I recommend Schluter Thinset that is available on Amazon. Click here to have yours delivered.

Grout is a very fluid substance that can easily get into cracks and holes in walls, as well as between ceramic and stone tiles. It is made of cement, water, and sand. Grout is not used as an adhesive to join two surfaces together. Rather, it acts as a filler, filling in gaps or holes.

Thinset (thinset mortar), on the other hand, is a cement-based product that is used to adhere tiles to floors and walls and is frequently used in mosaics. It is like grout in that it is made up of sand, water, and cement, but it also has adhesion-enhancing additives. This feature is what makes it stronger than grout because it has an adhesive quality that aids in bonding.

Grout and thinset are not the same, because they do not have the same structural strength; grout flows while thinset sticks. Because strong bonding between the floor tiles and the concrete surface is required, thinset is designed to be structurally stronger than grout. Grout is not as strong as thinset because the narrow spaces between tiles should be filled with a weak bonding material.

However, thinset can be used in place of grout in some cases, but the result won’t be aesthetically pleasing. You would have to clean as you apply because thinset sets quicker than grout. Thinset is also much thicker than grout, so it would not fill in the gaps and holes as well as grout would.

Can You Use Thinset as Grout for Mosaics?

You should not use thinset as grout because it will not fill up spaces and dry as efficiently as grout does. However, thinset might be suitable as grout for mosaics as long as the joints are thin.

Thinset is a cement-based adhesive that is used to join surfaces like tiles and concrete. A mosaic is a pattern or image created by arranging small, regular (or irregular) pieces of colored stone, glass, or ceramic on a surface and adhering them together using thinset mortar.

Mosaics can be made with a variety of different adhesives. Thinset mortar is particularly popular among mosaicists because it is waterproof and strong, making it ideal for outdoor mosaic projects such as murals and sculptures. Thinset mortar is also used for mosaics that may come into touch with water, such as in a shower because it is waterproof.

Grout fills in gaps and cracks between tiles on floors and walls, which is how thinset may be used as a Mosaic grout. You can either use only thinset mortar or mix grout with thinset to function as a filler between each piece when building a mosaic.

Depending on the mosaic project, combining thinset with grout changes the flow consistency and color of the adhesive. Combining thinset with grout would also be a good idea because it would readily fill in the gaps and dry quickly, giving the project a nice finish.

However, mixing grout with thinset is only suggested for Mosaics and not for other tiling applications, as mixing the two can compromise the thinset’s adhesive properties, decreasing its quality. It can be quite intimidating to work with Thinset mortar. Nonetheless, it is a necessary adhesive in the mosaic world and the preferred adhesive for external mosaics.

Can I Use Tile Adhesive as Grout?

You cannot use tile adhesive as grout because adhesive is used to secure tiles to walls or floors. Grout is only used to fill in the spaces between tiles. It does not have adhesive properties.

There are two common types of tile adhesives – ready-mixed and powdered. Here is some useful information on both adhesive types.

  • Ready-mixed adhesive:

As the name implies, the ready-mixed adhesive does not require further mixing before use and this makes it easier to use than powdered adhesive.

This adhesive is only suitable for walls and should not be used for installing porcelain or natural stone tiles. It is also not recommended for fixing tiles in wet areas such as a shower.

  • Powdered adhesive:

Powdered adhesives usually require more work than ready-mixed adhesives as they need to be mixed with water before use. However, they dry better and have greater strength. They are also suitable for fixing tiles in wet areas, unlike the ready-mixed adhesive.

Regardless of the type, the primary purpose of tile adhesive is to secure the tiles to the walls or floors; it is the glue that holds the tiles up. It is also used in installing and repairing cracked tiles.

Grout is the filler used to make those neat lines, providing a clean, finished look; it acts as a preventative measure against bacteria build-up, as it helps keep debris and dirt from accumulating under your tile. It also makes your tile installation strong and more rigid.

You should know that grout takes up a lot of time and requires meticulous work, and although leaving out the grout in the installation process seems like the easier option, you need to use grout if you want the job to last.

Using tile adhesive is a key process in the installation of tiles, and it has various substitutes, like the old technique of using a sand-cement combination, thin-set mortar, and others.

Grout also has other substitutes, like latex additives, caulk, and others; tile adhesive is not one of these substitutes at all.

What Should You Do If You Had Accidentally Used Mortar Instead Of Grout?

If you accidentally used mortar instead of grout, use a razor knife to dig out the mortar. After the mortar has been removed, apply the grout between the tiles.

When working on the tiles in your home, accidentally using mortar instead of grout can be scary, because using the wrong substance can have long-term negative effects. Thankfully, such a situation can be remedied.

Digging out the mortar with a razor knife is a lot of work that requires extreme care and focus, especially when the mortar has had enough time to dry and harden up. Another alternative for the razor knife is the grout removal blade oscillating tool.

To make the process of removing mortar a lot easier, you can pour boiling water on it, as this will weaken the mortar sufficiently for it to be removed.

Grout and mortar both have different purposes to fulfill.  Mortar is used to stick one material to another, while grout is used to fill gaps left in tiles as well as for sealing sections of precast concrete.

Some uncomplicated ways to differentiate between mortar and grout in the future are:

  • Grout is designed to flow into small gaps, and it is of higher viscosity than mortar.
  • Mortar is easier to work with, as it sticks to a trowel like a fluffy paste, grout on the other hand is less workable and is difficult to work with a trowel.
  • Grout has higher water content than mortar since it needs more water to achieve desired consistency.
  • Mortar has a higher drying time and is of lower strength than grout.

Can I Use Thinset to Fill Gaps?

Thinset should not be used to fill gaps, patches, or holes in your tiles. This is because thinset is not a filler and it may shrink at different rates during the curing process.

While it is common for amateurs to use thinset for patches and gaps, it is actually bad practice to do so. The primary function of thinset (or thinset mortar) is to be used as an adhesive for tile installation. This simply means that they are used to attach tiles to walls and floors.

Substituting thinset for fillers will not give you the best results. When the thinset shrinks, it creates an uneven look as some tiles will protrude over the others. The result doesn’t only look visually unappealing but can also cause you to hurt your feet.

Contrary to widespread belief, the gap or hole size is not a question that matters. The right thing to do is to use the proper materials for filling out holes and patches.

Grout is a better choice to fill your gap holes after tile installation. Using grout as a filler does not just fill the gaps between your tiles but also provides extra bonding and prevents cracks at the edges of the tiles.

Do You Need to Remove Thinset Before Grouting?

You should always remove the excess thinset from grout joints before grouting. Removing excess thinset is important as failure to do so leads to the thinset drying and becoming impossible to remove later.

Quite often, people make the mistake of letting their thinset dry off before they begin grouting. This delay could be very costly as attempting to remove dried thinset from the grout joint could be a chore.

Here is a chart that highlights what DIY forum users used to remove thinset from between tiles before grouting:

Method Used to Remove Thinset from Tiles Before GroutingPercentage of total results
putty knife (click for price)22%
grout saw20%
grout removal tool35%
utility knife12%
Dremel tool (click for pricing)11%

However, one cannot escape removing thinset before grouting. This is because failure to do so causes the thinset to show through the joints that have been topped up with grout.

Therefore, removing the thinset from grout joints during the tile installation process is advisable. Here are some quick steps to remove thinset from grout joints:

  • While setting your tile during installation, continuously use a damp sponge to wipe off excess thinset. To properly wipe off those in the grout joint, you could use a pencil or margin trowel to wipe it off gently.

If you do not have any of this, you could use any material that fits between the tiles but be careful not to shift the tiles while wiping.

  • It is not unusual to miss some spots while wiping. The missed thinset will dry off. To remove dried thinset, take a razor knife and gently scrape any you see from the surface of the grout joint.

Don’t bother with removing it all the way to the cement slab. Just ensure that you remove those visible in the grout joints. Afterward, you can use a damp sponge to clean off any discoloration your scrapping may have caused.

  • Just as done during tile installation, endeavor to wipe off the thinset that shows up during grouting or before the grouting dries up. For this, use a razor knife or corner of a margin trowel to dig out the thinset or a sponge to wipe out the edge.

For every thinset that you dig out or wipe, make sure to take it away from the work area, so it doesn’t contaminate another grout joint.

  • After grouting, do a last check for any visible thin sets in the grout joint. If found, you have to dig through the grout to remove the thinset. Digging could be tiring. Hence try to carefully remove all visible thinset before and during the grouting process.

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Aron Blake

I am the lead copywriter on Homezesty and the Webmaster. I have a lot of experience in home renovations and the creation of style. I enjoy writing and sharing my tips on how to create the best living environment. My Linkedin Profile, My Twitter Account

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