How to Remove Old Paint from Concrete?
Removing old paint from the surface is necessary in most cases when renovation and finishing work is carried out in the room.
In order to repaint ceilings, wallpaper walls or put tiles, it is necessary to remove the old coating, as it prevents the surface from bonding securely with other finishing materials. But under the sheets of gypsum board, you can hide the walls along with traces of the old finish.
Concrete is one of the most economical and low-maintenance flooring options. If you come across a concrete surface with fresh paint, it’s easy to clean: simply moisten the surface with water and then scrub with a stiff brush and detergent.
However, removing dried paint from concrete can be quite a tedious process because concrete absorbs paint easily. Although it may take a long time to remove dried paint, it is not impossible. Learn how to remove paint from concrete, step by step.
Use special detergents to remove paint, such as Dumond Smart Strip.
Dumond Smart Strip
How do I remove paint from concrete?
- Step 1: Clean the concrete surface and let it dry
- Step 2: Apply a paint remover
- Step 3: Allow time for the solvent to cure
- Step 4: Clean the surface
- Step 5: Finish with a pressure washer.
- Step 6: Repeat these steps until all paint is removed.
- Step 7: Wipe the surface to remove the paint remover.
Most chemical solvents designed to remove paint from wood can also be used on concrete and stone surfaces.
Make sure your paint remover is designed for the type of paint you need to remove. Some products only remove water-based latex paint, but there are products that remove both oil-based and water-based paints.
Look for an environmentally friendly product that is safe to use on both interior and exterior concrete surfaces. Such products are usually a thick gel that stays active long after application.
They are also biodegradable, odorless, and contain no caustic chemicals.
How to remove paint from concrete with chemical cleaners
- Apply a coat of solvent with a brush, following the manufacturer’s instructions.
- Allow the solvent to work until it is absorbed and the paint begins to soften (4 to 24 hours).
- Remove paint with a scraper as soon as it has visibly wrinkled or shriveled.
- If the paint is left on the concrete, reapply the paint remover to the area and allow it to work longer.
- Remove the residue with a hose or wipe it off.
- Clean the concrete with a degreaser.
Safety Tip: Do not use paint solvents that contain methylene chloride. These solvent-based cleaners are fast-acting but very toxic if inhaled or absorbed through the skin.
Proven ways to remove paint from concrete
There are not many ways to remove old paint from concrete, and the process in any case can not be called easy. To remove the old but tenacious coating, you will have to affect it with physical force and special tools.
The most unpleasant option is an oil composition, laid on the unplastered concrete surface. Let’s start with this option.
Option #1 – axe and spatula
This is an old and proven way to remove a layer of paint, while avoiding unnecessary cost. This is the preferred way to prepare the surface for tiling.
For this you will need:
- An axe and a trowel (both tools should be well sharpened),
- Sprayer with water,
- Safety goggles and gloves.
Use the axe to make frequent but not too deep cuts, then splash the wall with water and use a putty knife to clean up the cut. This is done until the entire surface is clean of the old coating.
Small notches putty is not difficult if you plan to paint the wall or stick new wallpaper, and for the mortar on which “sits” the tiles, such as a base – is the best option, as the bond will be very strong.
Pros: Cost-effectiveness, no harmful “side effects”, thoroughness.
Cons: quite difficult to physically deal with the old paint this way.
Option #2 – a drill with a metal brush attachment
On the one hand – very convenient, because most of the hard work will take the power tool, but the disadvantage is that the construction dust will stand a column. Protection for the eyes and respiratory organs must be in this case at the highest level. And then you will have to clean up for a long time.
Option #3 – a drill with a concrete drill bit or metal chain
The first nozzle is usually used to create cavities in the walls for outlets and switches, but also the paint is removed with their help very successfully if acts accurately and without excessive pressure. The coating will fly off in small pieces, so the dust will not be so much, but protecting the eyes is still necessary.
When working with a drill head in the form of a metal chain, it is important to ensure that an equal number of links remain on each side of it. Usually put on a chain of thirteen elements, that is, six working, plus one central, for which the design is attached to the electric device.
The method is also not too dusty, because the paint is removed by small splinters, but to protect yourself not only from them but also from the iron rings, which, deforming during operation, can fly ricochet off the surface directly in the face. If a link flies away from one side, the other side is also removed.
As a side note, you must use a chain of at least seven links in length, otherwise there will be no effect. If the coating is a thick crust, which is already bloated and cracked in places, you can try to make do with a chisel and a hammer.
Option #4 – chisel and hammer
If the surface has been painted more than once, and the coating is a thick crust, which is already bloated and cracked in some places, you can try to do it with a chisel and hammer.
These uncomplicated tools can in some cases provide excellent results since it is not difficult to remove paint from concrete whose adhesive properties have all but disappeared.
The chisel is held at an angle to the plane, and a hammer is struck on its handle. The old material comes away from the wall in rather large fragments.
Pros: relatively clean method, not at all expensive, works well if there is at least a token layer of plaster between the concrete and the paint.
Cons: Not suitable for removing a thin layer of paint from bare concrete, time-consuming; the chisel must periodically be sharpened, because you can only work with a sharp tool.
Option #5 is the thermal method.
When strongly heated, the old paint coating softens and blows up in bubbles, after which it is removed with a trowel. Warming the concrete base to such a high temperature is quite difficult, but it is possible if you use a powerful construction hair dryer.
Practiced the use of iron through a sheet of foil, but not as successfully. But using a blowtorch or a gas torch is simply dangerous: an open flame is a risk of ignition or burns.
You can only work with a respirator. It is better if one person heats the area by area, while the other quickly peel off the paint. This way, you can save a lot of time.
Advantages: minimum dust and physical energy consumption.
Minuses: emission of a large number of harmful substances during heating, increased difficulty when working with concrete substrate, as this material is extremely poorly conductive to heat.
Important: The method is not suitable for surfaces with hidden electrical wiring.
Option #6 – the chemical method
Quite in demand on the market of building materials is a paint remover; it is a caustic liquid, which includes solvents. When purchasing such a solution, you need to understand what kind of material you need to remove from the surface.
Organic based washes will help to soften and remove oil paint or alkyd enamel, and alkaline compositions are used against water emulsions and dispersions.
The mixture should be applied to the surface in one direction with a paint roller, hold for the time specified in the instructions and scrape off with a scraper.
Dispose of the residue as chemical waste; it should never be flushed down the drain.
It may be necessary to apply the paint stripper more than once or even twice if there are several layers of material on the surface and they are thick.
Pros: easy to apply.
Cons: high toxicity (in the case of organic solvents), a pungent, unpleasant odor, not the most affordable price.
Attention: the room, the walls of which were cleaned by this method, is subject to careful ventilation; protective mask is necessary when working.
In general, these methods are considered universal and are used to remove most old paint coatings from the walls. Some nuances exist only in the removal of old paint from surfaces with softer textures, such as wood, where forceful mechanical methods should be used with greater caution so as not to damage the very base of the material.