How to Paint Concrete That’s Already Been Painted

Concrete is incredibly strong stuff, and it's DIY-friendly, which is a great feature. Fresh concrete can be painted or tinted in any color you like...but do you know how to paint concrete that has already been painted?

When you're facing concrete that already has paint on it, the project becomes a little more difficult. The good news is that anyone can learn how to paint concrete that has already been painted, and you can get this done with basic tools and a fair amount of elbow grease.

Painting Concrete

In most cases, it's easy to paint concrete. Concrete surfaces are common in households, especially on exterior walls, floors, and surfaces surrounding the home.

It's a versatile material that's usually pretty easy to work with, and it's great for basements, garages, utility rooms, and outdoor areas of all kinds. But there is no perfect building material, and there aren't too many DIY projects that don't take a good amount of time and work, including painting concrete.

Concrete's rough texture makes it a piece of cake to get fresh paint to adhere to untouched concrete, which is a nice bonus of working with this material. And that's all great until it's time to repaint concrete and give it a fresh look.

When you need to paint concrete that's already painted, things start to get a little tricky. As a DIYer, you know what that means: you're going to need more tools, more time, and more effort than you used the first time that concrete was painted.

Repainting concrete surfaces is a bit more demanding than painting freshly-laid concrete. Aged concrete surfaces are coated with various things, such as staining compounds, sealants, and of course, older paint, all of which present difficulties.

However, it is possible to repaint concrete, and it is possible to do this on your own as a DIY. Assemble your tools and approach this project with a good game plan, and you can give your concrete a fresh new look within a matter of days.

How to Paint Concrete that is Already Painted

Concrete that already has paint on it is a daunting challenge, and you will spend more time repainting concrete surfaces than you spent painting them the first time. This is a project where you can't really use shortcuts, but if you follow all the steps and take the time to do it right, you won't have to repaint concrete again any time soon.

Clean and Scrape

Prepare a solution of water mixed with any household cleaning chemical. Scrub the concrete with the solution using a long-handled brush.

You will remove any debris, along with chipped or peeling, or flaking paint, using this technique. Allow the concrete surface to dry after cleaning.

Existing paint on concrete needs to be removed before you can repaint the concrete. This means the paint that's already there must be scraped and sanded.

Scrape any areas with loose or flaking paint, and lightly sand using fine (120 grit) sandpaper. Lightly sand intact areas of paint as well to give them the grit needed to receive new paint.

Clean the concrete with a dry mop. There should be no loose, chipped, or flaking paint anywhere on the concrete and the concrete should be relatively paint-free.

Don't exhaust yourself trying to remove every single bit of paint. As long as it isn't chipped or peeling and as long as you've sanded it to give the paint a rough surface, you won't have issues repainting concrete even if the older paint is still there.

Buff

Use a buffer to completely remove any loose pieces of paint and create a nice, uniform surface to work with for your new paint. You can rent a floor buffer from just about any hardware supply store.

Make sure the concrete is completely dry before you move on. Paint won't adhere well to moist concrete, and you won't get good coverage.

Exercise caution while using the floor buffer, which is a powerful and large machine. You have probably seen these devices being operated by custodians in public spaces, such as in schools and hospitals.

Work slowly and precisely, and if you have any troubles, just turn off the machine to get yourself sorted and get back on track.

Examine

Inspect the dry, buffed concrete surface for curing compounds. After the buffing, the curing compounds are revealed in the form of small spots below the old paint.

If you see these spots, you will have to treat the concrete before it can be repainted. Prepare a solution of denatured alcohol and hydrated lime in equal proportions.

Denatured alcohol is ethanol that has several additives mixed into it, and this is extremely toxic and poisonous, so use caution when handling this chemical and keep it out of the reach of children and pets at all times. Make sure the bottle is clearly marked as poison and store it somewhere up high when it's not in use.

Hydrated lime is, basically, a mixture of quicklime and water. It may also be marked and sold as builders lime, caustic lime, slaked lime, pickling lime, or cal.

Hydrated lime is used to remove acid and impurities from a variety of materials, including metal. It is often added to concrete mixtures to make the material more water-resistant.

Mix the solution using a plastic spatula until it develops a paste-like consistency. Apply this paste on all the visible spots on the concrete.

Give the paste time to dry until it hardens into a thin crust. Scrape away the dried spots with a bristled brush and sweep away any residue of the dried solution with a broom.

Prep the Concrete

Fill any small holes or cracks in the concrete with a patching compound. This will make your concrete look new and fresh again after it's all painted.

Place painter's tape all around the border of the concrete where it meets the floor, the ceilings, other walls, and so on. The tape should be just outside the concrete on the surfaces you don't want to paint.

Latex paint is fine for concrete inside the home, but only in little-used areas. Oil-based epoxy paint is much tougher and made to withstand heavy use and high traffic.

Oil-based epoxy paint is what you'll want to use for most of your concrete areas. This paint will hold up very well even in outdoor environments, so with normal to heavy use and wear and tear, you won't need to repaint concrete for a few years at least.

Buy thinning agent to go with your epoxy paint, as you will need to mix the thinner into the paint before you use it. Do this only when you're ready to paint, as literally the last step before you begin to apply the paint.

When using epoxy paint, only mix enough of the two parts of the product to be used immediately. Epoxy paint cannot be stored once the two parts are mixed, and any leftovers must be disposed of properly.

The best way to dispose of epoxy paint is to leave it in an open paint can and let it dry out until it becomes a solid. It can then be thrown away with normal household trash.

A respirator must be worn when using epoxy paint. Additional protective gear, such as safety goggles, is also advised.

Exposure to the chemicals and fumes in epoxy paint can be dangerous and toxic. Work only in a well-ventilated area if you're indoors, and set up a fan nearby to circulate air.

Paint the Concrete

Start by painting the edges of the concrete surface using an angled three-inch standard paintbrush. Paint all the edges, cutting in around corners and angles as needed.

Use the brush to paint any small areas where a roller will not fit to get complete coverage. Wider spaces will be painted with the roller, so you don't have to use the brush for the entire concrete area.

Use a paint roller to cover the rest of the concrete. You'll use the roller in the standard way—by pouring some paint into a tray and rolling the roller in the paint before applying it in long, even strokes across the concrete.

Allow the first coat of paint to dry according to the recommendation on the label. You will probably be waiting for the paint to dry anywhere from 10 to 24 hours.

Even if the paint looks and feels dry, do not try to jump ahead of this process. Let the paint dry for as long as the label on the can says it needs to dry, and don't go by feel, unless the paint is still wet or sticky even after the recommended time has passed.

If you live in a very humid environment, paint can take longer to dry than the label recommends. It's okay to add more dry time to your overall project timeline, but don't try to beat the clock by waiting for less time for paint to dry.

Apply the second coat after the paint is completely dry. Now, wait for about five days and take a long look at your paint.

Now's the time to decide if you need another coat of paint. If you do, apply it and allow the paint to dry again.

If you don't need another coat, you're ready to seal and enjoy your painted concrete.

Seal It

Moisture and wear can take a toll on painted concrete, even when you're using tough epoxy paint.

Use a clean paint roller to apply masonry or concrete sealer all over the painted concrete. You will probably need to do at least two coats of sealer and possibly more, depending on manufacturer recommendations.

Allow the sealer to dry thoroughly between coats and after the final coat is applied.

Paint Concrete that Has Already Been Painted

You will have to work for it, but it is very possible to paint concrete that has already been painted, and you can end up with a beautiful final result. Painted concrete looks very nice and the paint will last without chipping or showing a lot of wear for a few years.

Take the time to do the job properly so you get a beautiful finish, and you will be happy with the results.

Repainting Concrete FAQ

How long does it take to repaint concrete that already has paint on it?

It takes several days, up to two weeks, to repaint concrete. You will spend time first removing the old paint, a process that takes several steps.

Once you finally get the old paint removed, painting the concrete will take up to one week because you need to let the paint dry fully between coats and wait a few days to see how the final result is and whether you need a third coat of paint to finish the job.

After all that, you will need to seal the concrete, and that takes a couple of days at least. Once all the work is done, however, you won't need to worry about the concrete for a few years, so you can get back to just enjoying our hard work and DIY skills.

How much does repainting concrete surfaces cost?

One gallon of epoxy paint costs around $50, depending on the brand you purchase. The thinning agent costs $10 to $25, on average, depending on the amount you buy.

You will also need paint brushes, paint rollers, paint trays, and painter's tape, along with scrapers and brushes. All of these tools are needed to remove old paint, apply new paint, and seal the concrete.

Add safety glasses and a respirator to your shopping list. All in all, you will spend $100 or more on various tools and equipment needed for the job.

Why do you have to use epoxy paint on concrete surfaces?

Concrete can be painted with latex-based paint, the type of paint you would use on drywall, but it's not advisable in most situations. If your concrete is outside or it's a floor or counter, the material will see a lot of use, and that means there will a lot of wear and tear on the paint.

Epoxy paint resists chipping and wear very well, and it's ideal for high-traffic areas. This paint sticks well to concrete and will create a nice, even coat of color when properly prepped and applied.

You can use other paint on concrete, but epoxy is definitely your best option, and it will last the longest.

Can you paint over previously painted concrete?

Concrete that has paint on it can be painted again. As long as you have a clean, smooth surface to work with, there's no reason you can't add new paint.

If there are areas of damage, chipped paint, or other problems, you will need to smooth these areas out before you paint.

How do you prepare previously painted concrete for painting?

Before painting a painted concrete surface, sand down any loose or peeling areas of paint. You can do this with a wire brush or with sandpaper.

If the paint on the concrete is glossy, rough this up by sanding it because the new paint won't stick as well to a glossy surface like that.

Do I need to prime previously painted concrete?

Before applying new paint, prime the concrete so that the new paint will stick well and the color will show up nicely. Allow the primer to dry completely before applying paint.

What is the best paint to paint over painted concrete?

There are many types of paint that work well with concrete. Masonry paint, epoxy-based paints, and acrylic latex paint are all good choices.

Why won't my paint stick to the concrete?

If your paint doesn't seem to be sticking to the concrete, it's likely due to atmospheric conditions. If there's a lot of humidity, the paint won't want to stick, and it won't want to dry well, either.

Moisture that is seeping up from the ground, or damp concrete, will also make it difficult for paint to stick.

Apply one or two coats of primer and allow them to dry thoroughly. This will make it easier for the paint to stick to the concrete.

Further Reading

5 Painting Tips for a Smoother Finish

9 Steps to Painting Like a Pro

Basic Painting Tips Every DIYer Should Know

Choosing the Right Paint for Your Home's Exterior

How to Resurface Concrete Steps

How to Pour Concrete

How to Resurface Old Concrete

How to Stain Concrete Paving Stones

Mixing Concrete for the Beginning DIYer

Oil-Based Paint vs Water-Based Paint

Why Aren't You Making Stuff Out of Concrete?