Pressure washers are great tools to have in your home, as they can make otherwise time-consuming cleaning tasks take a fraction of the time and manual effort.
They are able to remove dirt, grease, and even rust from a variety of surfaces from wood through to metal. Can they be used to strip paint from concrete?
A pressure washer can be used to remove paint from concrete. A washer capable of higher pressures (usually between 2000 – 4000 psi) is generally needed. The effectiveness of the paint stripping will be affected by what kind of paint has been used, the attachments on your pressure washer, and whether or not the concrete has been sealed.
When to remove paint from concrete
If you’ve ever spilled some paint (particularly an oil-based paint) on concrete then maybe you’ve just accepted that it will be there forever.
Concrete is a porous material, which allows the paint to actually seep into the material itself, meaning removal can be quite tricky. Paint stains on concrete can end up looking quite unsightly and so it’s always best to try and get them out.
Another reason you might want to remove paint from your concrete surfaces is to update the paint job.
Old paint can start to peel and flake (especially outside paint exposed to the elements) and make it necessary to repaint the whole surface. To do this effectively, all the old paint needs to be completely removed and the surface cleaned to essentially start from scratch.
Like most outdoor DIY jobs, it is probably easier to have this on your list of Summer chores. The slightly higher temperatures make the stripping a bit more effective and will cut the time down a little, as well as just being generally more comfortable.
What pressure and nozzles should you use?
For stripping paint, especially oil-based paints, you’re going to need a pressure washer that can deliver pressures on the higher end of the spectrum. Much like the removal of rust from concrete surfaces, about 3000 psi is a good pressure to aim for.
Lower pressures will likely not have any effect on oil paint and concrete is able to withstand some of the higher pressures. Moreover, if the concrete was treated with sealant before the paint was applied, then the paint will not have had a chance to seep into the pores yet and the concrete will be able to take even more pressure without being damaged.
If the paint you’re removing is an old paint job that is flaky and peeling then a lower pressure will definitely help to remove the surface flakes before going for the harder part. Be sure to wear something protective over your eyes in this case as there will be flecks of paint flying around!
For the preferred nozzle, this will depend on how large the surface is and how stubborn the paint is as well as how thorough the pre-clean job needs to be.
In this instance, a 0 degree (or laser) nozzle is not recommended, as this could cause chips of concrete to become loose and pose a safety hazard, as well as causing lasting damage to the concrete surface.
A 25-degree nozzle will be suitable for most of the cleaning as this will get rid of grime and dirt, as well as loose paint.
Dropping the angle to a 15-degree nozzle will give the increase in pressure needed to start stripping off the main paint layers.
When stripping paint from walls, holding the washer so that it sprays at an angle downwards will direct all the stripped paint away from the surface. Maintaining a distance of between 12 – 18 inches from the concrete is optimal for allowing the water to get under the paint layers without damaging the concrete.
What chemical products might you need?
If you know anything about stripping paint, then you’re probably already wondering if you might need something stronger than just simple detergent (or even just water on its own) to remove the paint.
There are a variety of different paint strippers that can be used which will make this job easier. These will depend on the type of paint used.
Stains arising from spray paint can often be quite stubborn, but will eventually come off with soapy water. However, an application of a stain remover that contains trisodium phosphate (found in many common household cleaners) will make this much easier. If it is applied to the paint stain and left to seep into the concrete for a few minutes prior to washing, then once the pressure washer is used the stain will be lifted.
There are more powerful paint strippers that can achieve similar results with most paints. In theory, it is best to use an oil-based paint stripper to remove oil-based paints but if you’re not sure which kind of paint was applied, an oil-based paint stripper is your best bet.
These paint strippers often contain methylene chloride (also called dichloromethane) which is quite harsh, so when using these, take care to only use it in well-ventilated areas and/or wear a covering over your mouth/nose.
For latex paint spills, these are water-based, so getting them wet as soon as possible is a big plus. For dried stains, ammonia (which is a common household cleaner) can be used. If the stain is very old and quite thick, then a water-based paint thinner can be applied, and the stain washed with the pressure washer once the thinner has had time to take effect.
The same can be true for acrylic paint spills, as these are also water-based.
One type of paint, epoxy paint, is very unlikely to be removed using a pressure washer. This paint is designed to bind to concrete for “lifetime coverage” and so is not prone to easy removal! There are some solvents that can be applied to attempt removal, such as lacquer and acetone (acetone is a major component of nail polish remover), but most removals of epoxy paint use a floor grinder to scour the paint off.
As with any chemical method of cleaning, you may want to completely avoid any harsh/toxic chemicals if you have pets or children. As such, using just soapy water or detergent (even just water on its own) will eventually lift the paint off your concrete surfaces, but it will take considerably longer and may not give you full coverage where some stains are older.
Can you strip paint from other surfaces with these methods?
These methods of paint removal are applicable to most surfaces that you would want to remove paint from.
For wood surfaces, it is best to follow the grain of the wood when pressure washing, rather than following the “spray downward” advice given earlier. A lower pressure should be used as well, closer to 2000 psi.
Similarly, a lower pressure wash can be used to strip paint off brick surfaces. Higher pressures would be very prone to breaking the bricks and sending chips flying everywhere so a much lower pressure and wider nozzle angle is best.
Pressure washers can make the removal of paint from concrete (and other) surfaces much quicker and easier. The fact that so many different paint strippers are available means that almost any paint stain can be removed, leaving your concrete surfaces clean and clear year-round.