The best methods for removing paint from concrete prior to tiling are:
- Applying paint stripper
- Using a large sander to strip off paint
- Power washing painted outdoor concrete surfaces
- Soda or bead blasting indoor concrete surfaces
- Resurfacing the floor with additional concrete
- Using a floor grinder to remove the paint.
Each of these methods can be applied regardless of the type of paint that was used on the concrete slab. Depending on the size of the floor, different options may be preferable.
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Do You Have To Remove Paint From Concrete Before Tiling?
If you attempt to tile over painted concrete, the tile will pop up shortly after installation. This is due to the fact that thin-set mortar used to glue down tiles will not adhere properly to painted concrete. In order to tile over painted concrete, you have to strip away the paint first.
- Always strip away paint before installing tile on concrete.
- Tile installed on a painted concrete floor will pop loose.
- Improperly installed tile that pops loose will often have to be discarded and replaced with new tile.
Do not attempt to take a shortcut and tile over painted concrete. When the tiles pop up it will be very hard to re-use the tiles. The mortar and paint fused to the back of the tile will likely mean you have to throw away the tiles and start over. Prepping a concrete floor for tile installation saves you time, labor, and money.
6 Ways to Remove Paint From a Concrete Floor for Tile Prep
There are several ways to prep painted concrete for your new tile floor. The method of choice depends on the space, as well as what tools you feel comfortable using. Here are the best options for removing latex paint or oil paint from concrete.
Paint stripper will peel paint off your concrete with very little labor on your part. Choose a paint stripper that works well on both oil- and water-based paints. Then, pour a portion of paint stripper onto the ground before spreading it evenly with a paint roller on a long handle. Start at a corner of the room and work toward the exit.
- Use this paint stripper that will remove all types of paint.
- Wear protective gloves, safety glasses, and a breath mask when working with paint stripper.
- Pour paint stripper onto the concrete and spread with a roller on a long handle.
- Allow the paint stripper to sit for the recommended time according to the product label.
- Remove the paint with this long-handled scraper.
- Discard scraped paint in heavy duty trash bags
- Repeat for areas with stubborn paint if necessary.
After application, wait 30 minutes for the paint stripper to work. Then, while wearing gloves, safety goggles, and a vapor-filtering mask, use a long-handled scraper to remove the paint and discard it. If there is still some stubborn paint, repeat the application on the areas where paint remains.
To remove paint from concrete in a large space, rent a commercial floor sander from your local hardware store. A floor sander will quickly strip away paint and reveal the concrete below. For smaller spaces, use a belt sander or orbital sander to strip away paint. A smaller sander is also useful for sanding paint at the edges of rooms where a large floor unit may leave some paint behind.
- Rent a large floor sander to strip paint from large rooms.
- Use a belt sander to strip paint from small rooms.
- A belt sander or orbital sander is great for removing paint at the edges of a room where a floor sander is ineffective.
- Wear eye and ear protection whenever you are operating a power sander.
- Always wear a NIOSH/MSHA approved mask when sanding concrete.
No matter what size of sander you use to remove paint from your concrete floor, wear eye and ear protection while working. It’s also essential to wear a particulate-filtering mask to ensure you don’t breathe in any paint particulates.
If you are removing paint from concrete in outdoor areas, consider using a power washer. With nothing but water, you can blast through stubborn layers of paint. You can quickly transform your entire floor into a clean, paint-free surface. This is accomplished without chemicals or expensive equipment since a good power washer can often be rented from your local hardware store.
- Rent a power washer to blast paint off concrete in outdoor areas.
- Use a power washer for outdoor spaces ONLY.
- Do not use a power washer to remove paint from concrete floors indoors.
Because power washers use high-pressure water to remove paint, this method should be used for outdoor areas only. While this option is great for patios, do not use it indoors. The water will damage walls, ceilings, and electrical components if used indoors.
A soda blaster uses baking soda sprayed at high velocity to scour paint off concrete. This is a great choice for indoor areas where power washing is not an option. Because baking soda is non-toxic, it’s a safe way to remove paint. Just scour the paint off by soda blasting, then vacuum up the baking soda and paint residue when you’re finished.
- Rent a soda blaster from a reputable tool company, such as this one.
- Wear eye and ear protection, as well as a particulate-filtering mask when operating a soda blaster.
- After the paint is removed, vacuum up the paint and baking soda to complete the job.
Work with a reputable tool dealer in order to rent a high-quality soda blaster and industrial-grade baking soda for the job. You’ll need specific tools and supplies for this job, but soda blasters are one of the quickest and least toxic ways to strip a layer of paint from concrete.
If your painted cement floor is damaged, pitted, or uneven, it may be best to resurface it before tiling. Resurfacing concrete involves pouring a new layer of concrete over the old one. This work can be messy. It also requires a lot of work to pour, spread, and smooth the concrete. It is best used when the concrete is damaged and requires repair before tiling.
- Resurface damaged concrete floors with a new layer of concrete.
- Clean the floors with soap and water, then allow them to dry.
- Mix bagged concrete to an oatmeal consistency.
- Spread the concrete over the existing surface to a depth of 1/8–1/4-inch.
- Allow concrete to cure for at least 24 hours before you begin tiling.
Before resurfacing, clean your floor thoroughly. Then, mix bagged concrete. Finally spread a layer of concrete 1/8–1/4-inch thick (3–6 mm). Spread the concrete so it provides a smooth, even surface that completely covers the old surface. Then, allow the concrete to cure for at least 24 hours before tiling.
Similar to sanding large areas, you may choose to use a floor grinder to scour away paint. As with a large floor sander, you will have to lease a floor grinder from a tool rental company. A floor grinder will make quick work of large areas. For small rooms and detail work, use an angle grinder equipped with a diamond grinding blade.
- Rent a floor grinder such as this one to grind paint off your concrete surface.
- Use an angle grinder to remove paint at the edges and corners of rooms.
- Wear earplugs, goggles, and a particulate-filtering mask whenever you are using a floor grinder.
Always wear eye, ear, and breath protection when using a grinder on painted concrete. Work carefully—these are high-powered tools that can damage concrete if you grind too much in a single location.
How Do You Remove Paint From a Concrete Floor Before Tiling?
It is essential to remove paint from a concrete floor so that your tiles do not come loose. In order to remove the paint, apply a paint stripper or blast the paint off the surface with a power washer or soda blaster. Alternatively, you can use a floor sander or floor grinder to scour the paint off the concrete prior to tiling. If the concrete surface is pitted, uneven, or cracked, consider resurfacing the floor with a new layer of concrete before tiling.