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Will Thinset Stick to Painted Drywall? (Explained)

Thinset is a type of special mortar that is specifically made for tiles. It is usually used to attach the tiles or stone to surfaces like drywall, cement or concrete.

However, if you are wondering whether thinset sticks to painted drywall or not then you are in the right door. Today we will be having a detailed discussion on this topic.

So, without any further due let’s get started.

Will thinset stick to painted drywall?

Thinset will stick to painted drywall. In fact, thinset bonds best with porous surfaces. You do not need any sort of preparation to apply thinset. However, you need to make sure that the surface is clean enough. And if you are applying it on the walls or tiles make sure the shiny part is removed.

The thinset will stick over painted drywall. Additionally, keep in mind that thinsets bond best with these sorts of surfaces. However, the glossy parts need to be removed. You can never tile on a glossy surface.

Apart from that, you can tile and apply thinset on a painted wall. If you are planning to renovate your kitchen or bathroom and plan on using thinset , it is not mandatory to remove the existing paint.

However, you may want to rough up the painted surface so that it has a texture and the tiles can bond properly.

Unmodified thinset stick to painted drywall:

Unmodified thinset will stick to painted drywall. This material will bond very well with sheetrock and other surfaces.

Unmodified thinset will not stick as painted walls can gather up tons of moisture in it. Therefore, it is better not to use unmodified thinset on painted dry-wall. However, before you plan on applying, consider the purpose.

Additionally, thinset comes in two different colors. So, choose the color that you think will be ideal for applying on the tiles.

Modified thinset stick to painted drywall:

Modified thinset can and will stick to painted drywall. However, there are things that may require your attention  such as the moisture level in the paint. If the paint is waterproof, you can easily make the thinset stick to painted drywall.

The curing process cannot happen properly when there is moisture present in the wall. Therefore, the paint needs to be latex-based.

While choosing the thinset, choose the colored thinset that is the closest to your tile color. Thinset comes in white and grey color.

Choose the one you think will be ideal for the new look you’re going for.

How well does thinset stick to painted drywall?

Thinset sticks with painted drywall well. Thinset or modified mortar will bond best with purpose surfaces. Removing the paint and doing it all over again can be a hassle. However, when you do not want to re-do all these, you can just remove the shiny-finish.

Once you remove the shiny-finish the surface becomes rough. As the surface becomes rough, it turns porous. Porous surfaces are well known to bond and stick well with tiles and the thinset in between.

Herefore, if you are planning on using thinset on painted drywall, then make sure to prepare the walls.

What kind of thinset do you use for painted drywall?

You can use modified thinset for painted drywall. Modified thinset comes with a polymer that affects the bonding strength. As you are planning on applying the thinset on the painted wall, it’s better to use a modified thinset.

Modified thinset have higher bonding capabilities. A rough,porous surface and modified thinset makes the perfect duo. However, there are conditions that you need to ensure before, applying thinset on your painted walls.

To adhere tiles with thinset, the surfaces need to be roughed up. Especially if the walls are designed. Therefore, try to use modified thinset.

Can you thinset over drywall?

You can thinset over drywall. Surfaces like drywall, and backer board are considered porous. And thinset will bond the best with such surfaces. They wouldn’t additionally need any preparations. However, painted drywall will.

However, while applying thinset over drywall you need to make sure the area isn’t too much exposed to moisture. As you apply the thinset, make sure that the area does not come in contact with water.

If the moisture level is high, the curing process will not occur properly. This makes the bond between the tiles and the drywall weak.

Apart from that, too much moisture can also cause growth of debris in between the tiles. Which may later spread out all over the place. Therefore, you can apply thinset over drywall. 

Will thinset stick to damaged drywall?

Thinset will not stick to damaged walls. Modified mortar or thinset works great with rough surfaces, however not the damaged ones. The tiles may not adhere well with the damaged drywall.

Removing the damaged drywall sheets and then applying the thinset makes it easier for the tiles to adhere well. You are most likely to find cracks and holes in the drywall as soon as it starts to get damaged.

Before you plan on applying thinset over it, you need to ensure that you repair the damaged drywall. Therefore, you cannot and should not use thinset over damaged drywall.

Can you apply thinset mortar over paint?

You can apply thinset mortar over paint. Painted walls are not an issue unless the paint is not waterproof. If the paint absorbs moisture it may not adhere well to the thinset.

Thinset over latex paint:

It is possible to apply thinset over latex paint. Latex paint does not absorb water. It is considered waterproof. However, if you are using the thinset over a latex paint that has a glossy or shiny finish, that needs to be removed.

The glossy finish may become an obstacle for the thinset and tile to adhere. Additionally, rough surfaces are better when it comes to applying thinset on painted drywalls.

How to prep and apply thinset to painted drywall?

Modified mortar or thinset is usually known to have a better boding capability. In most cases, you don’t need to prep the walls to apply thinset. However, in some cases you may need to.

Here are a few steps that you can follow to prep and apply thinset on painted drywall:

Sanding down the old painted wall:

Before you apply thinset, the walls need to be turned into a rough surface. To sand down the walls you can use 80-120 grit sandpapers on a sander’s pad.

You may want to continue sanding the area until it has lost its shine. Once done, use a damp rug to wipe down the sanded wall and let the wall dry.

Taking measurements:

Measure the width of the wall and divide the number by two to find the center. Additionally, also measure the height of the wall with a tape measure.

And add up an ⅛ inch of height to the measurement and place a vertical line. Pull up a line horizontally on the line to place your first tile.

Applying thinset:

Apply a thin layer of thinset under the horizontal line with the help of a grooved trowel. Put your first tile where the two lines meet. Continue the installation process.

Seal the tiles using grout:

Once you are done installing the tiles, you can apply grout to seal the tiles. After the application of grout, wipe the tiles with a damp sponge and remove the excess.

Final thoughts

Thinset will stick to painted drywall. Thinset or modified mortar are made to bond well with porous and rough surfaces. However, before applying thinset on a painted wall, you need to ensure that the wall paint does not have a glossy or shinny finish.