How to Remove Paint From Concrete? (Oil & Water-based)

Most people believe removing paint from concrete is hard, but it isn’t. So, how to remove it?

To remove paint from concrete, use a chemical-based or solvent-based paint remover. The paint remover will penetrate the coating and destroy the bond between the particles. Once the particles aren’t bonded, you can wipe the paint off the concrete surface.

However, the concrete paint removal method depends on the paint type. You can use soapy water for water-based paints, but for oil-based paints, you must use chemical-based paint remover.

How To Know The Paint Type?

How To Know What Type Of Paint You Have In Your Concrete?

The type of paint will determine the removal method you will use. Here’s how to find the type:

1. Try To Remove It

To know the type of paint the concrete has, wipe the surface with a rag (or cotton ball) soaked in alcohol. If the paint comes off on the rag, it is water-based. If it doesn’t come off on the rag, it is oil-based, or the surface is sealed. 

Rubbing alcohol isn’t capable of removing oil-based paints or sealants.

2. Use The Water Test

You can use the water test to know the type of paint. To do this, put a few drops of water over the surface, and wait a few minutes. If the water soaks into the concrete, the paint is water-based. If the water doesn’t soak into the surface, the paint is oil-based, or the concrete is sealed. 

3. Feel The Texture

You can also feel the texture of the finish to know the type of paint. Run your fingers over the surface. If the finish feels slick and glossy, the paint is oil-based. If the paint feels dry and textured, it is water-based. 

When dry, oil-based paints have a glossy and slick surface, while water-based paints have a dry and textured finish.

4. Light Test

Expose the concrete paint to a light source. You can use your phone flashlight. If the finish looks shiny, it is oil-based. If the finish looks dry and textured, it is water-based.

How To Remove Water-Based Paints From Concrete?

How To Remove Water-Based Paints From Concrete?

Method #1: Use Water-Based Paint Strippers

You can use water-based paint strippers to strip water-based, latex, and acrylic paints. You must apply the stripping paste over the surface, and wait until it absorbs the paint. Once the stripping paste gets dry, you must remove it with a paint scraper. 

Here is a guide on how to do this:

  1. Wipe the surface to remove dust.
  2. Apply two coats of the paint-stripping paste on the surface.
  3. Spread the stripper paste using a putty knife.
  4. Leave the paste to dry for about 30 minutes.
  5. Use a metal putty knife to remove the stripper paste and the absorbed paint.
  6. Reapply it for leftovers.

Method #2: Scrub the Finish Off

Water-based paint uses water as its solvent so if its coating is exposed to water (or moisture), it will get softer. So, you can strip it by applying soapy water over it, and then scrubbing the coating off with a hard brush.

Here is a guide on how to do this:

  1. Clean the surface to remove dust or filth.
  2. Mix water and detergent in a clean bucket.
  3. Apply the mixture onto the surface. You can do this at intervals. 
  4. Wait until the coating develops bubbles.
  5. Scrub the coating off with a hard brush.
  6. Wash and rinse the surface.

Method #3: Scraping and Sanding

To scrape, use a metallic putty knife and scrape most of the paint. To sand, use a power sander and sand the finish off. You must use rough sandpaper to remove it.

Here are a few things you should know about scraping:

  • You can damage the scrapper. 
  • It can cause scars and marks on the surface.
  • It’s best to use it if the coating is still wet.

How To Remove Oil-Based Paints From Concrete?

How To Remove Oil-Based Paints From Concrete?

When dry, oil-based concrete paints have a glossy finish, making their finish hard and moisture-resistant. Since they use oil as their solvent, its finish doesn’t dissolve (or get removed) in water. So, you must use solvent-based or paint strippers to remove them.

Method #1: Using a Solvent-Based Product

The solvent-based paint remover will dissolve the particles of the coating and soften it. Once the coating is soft, you can scrape it with a scraper. 

Here is a guide on how to do this:

  1. Clean the surface.
  2. Prep the solvent-based paint remover by following the manufacturer’s instructions.
  3. Apply two coats over the affected spots.
  4. Wait 1 hour. 
  5. Use a scraper to remove the solvent-based remover.
  6. Wash the surface to remove residue and leftovers. 

Method #2: Using Petroleum-Based Solvents

Petroleum-based solvents are liquid formulas gotten from crude oil distillation. These solvents are potent enough to dissolve oil-based paints. The solvent will dissolve their glossy finish and make it easier to wipe it off. 

Here is a guide on how to do this:

  1. Apply the petroleum-based solvent to the affected spots.
  2. Wait for a few minutes for the paint to get dissolved.
  3. Once the coating starts to bubble, wipe it off with a clean rag.
  4. Clean the surface.

You must clean, wash, and rinse the surface to remove the petroleum-based solvent residue. If you don’t remove the solvent residue, the new paint coating won’t stick.

Method #3: Sandblasting

Sandblasting will strip oil-based and sealed paint. The sandblaster will expel sand (or mineral rust) at high pressure over the finish and remove it. 

Here is a guide on how to do this:

  1. Wear a pair of goggles. 
  2. Fill the sandblaster. 
  3. Connect the sandblaster nozzle.
  4. Aim the nozzle directly on the concrete.
  5. Turn on the sandblaster and compressor.
  6. Do this about 3 times to remove the finish.

Don’t use an industrial or large-size sandblaster as they are too powerful and will damage the concrete. Instead, use a cabinet blaster or mid-range sandblaster.

How To Remove Spray Paint From Concrete?

Spray paints stick to concrete better because they are expelled at high pressure from the sprayer. This means they penetrate the surface deeply, and you must use a more effective method to remove them. Here are the top 2 methods to remove it.

Method #1: Use a Sander

Use a palm sander, orbital sander, or a grinder to remove spray paint. Power sanders are aggressive enough to strip the finish without damaging the surface under it.

Here is how to do this:

  1. Clean the surface.
  2. Turn on the sander or grinder.
  3. Use rough sandpaper and sand the concrete with a sander in a circular motion. 
  4. Sanding produces a lot of dust. So, remove the dust and inspect the surface.
  5. Clean the surface. 

You can manually sand small-sized surfaces. However, for large surfaces using a power sander is necessary. 

Method #2: Using Solvents

You can use mineral spirits or denatured alcohol to strip oil-based spray paint. The solvent will dissolve the particles and make the coating liquefy. 

Here is a guide on how to do this:

  1. Clean the surface.
  2. Soak a clean rag in the solvent.
  3. Use the dampened rag to wipe the coating repeatedly.
  4. Wait 1 hour.
  5. Scrub the coating with a toothbrush.
  6. Wipe off the finish with a clean rag.
  7. Wash and clean the surface.

Other Things You Can Use:

1. Vinegar

You can use vinegar to remove flat, satin, and semi-gloss paints. However, you shouldn’t use it to remove oil-based paints. 

Here’s how to use it:

  1. Mix the vinegar with clean water.
  2. Damp a rag into the vinegar mixture. 
  3. Use the dampened rag and wipe the finish.
  4. Wait a few minutes. 
  5. Once the coating starts to bubble (or peel off), wipe it off with a clean rag. 
  6. Remove the vinegar residue. 

2. Baking Soda

You can use baking soda to strip paint. Baking soda is a high-alkaline solution that will break the bond between particles and cause the coating to liquefy:

Here’s how to use it:

  1. Mix a few tablespoons of baking soda in boiling water. 
  2. Pour the mixture into the coating. 
  3. Wait 1 hour. 
  4. Once the surface gets dry, scrape the paint. 
  5. Remove the residue.

3. Pressure Washer

You can use pressure washers to remove water-based or un-sealed paint. To do so, use a pressure washer with a PSI between 2000-4000. If you use lower pressure than 2000 PSI, you won’t be able to remove it.

5. Muriatic acid

Muriatic acid is a mild acid that is strong enough to strip off all types of paints.

Here’s how to use it:

  1. Apply the muriatic acid over the affected spots>
  2. Wait 15 minutes.
  3. Wipe off the coating.
  4. Remove the muriatic acid residue.

The muriatic acid residue will cause concrete etching if you don’t remove it. 

6. Paint Thinner

Paint thinners are solvents designed to liquefy or dissolve the paint, so you can use them.

7. Acetone

Acetone is natural paint remover and will strip paint from different surfaces. Also, the solvent is safe to use on concrete. Just apply it to the surface and wait a few minutes for the paint to dissolve.

Final Words

Stripping paint off concrete isn’t hard, but you need the right tools and guidance. In this post, we have explained 9 different methods on how to do it. 

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