Are you looking for the best way to clean a concrete patio? I've tried and tested three popular cleaning methods for removing stains, grease, mold, and algae from concrete surfaces. You won't believe the results! (Also works for concrete floors and driveways).
Are you thinking of replacing your concrete patio because it's full of hard-to-remove stains, grease, or mold? Let me tell you, you are not alone! We chose concrete slabs for our patio because they are inexpensive but durable, exactly what we needed after spending all our money on building a house.
At first, the lookalike sandstone patio slabs looked beautiful. The slabs only needed a quick brush down to remove leaves and dirt to get them looking clean again.
After a few years, we noticed grease stains, green algae, black mold, and rust stains building up on the concrete patio slabs.
The mold and algae were especially prevalent in shady areas like under overhanging plants around the edges of the patio and underneath the patio table and chairs. There were even some paint and oil stains leftover from the various DIY and bike repair projects we've done on the patio over the years.
Table of contents
- Concrete stains
- Garden re-design
- Patio cleaning without damaging the grass
- Preparing to clean a concrete patio
- Best way to clean a concrete patio with baking soda
- Best way to clean a concrete patio with vinegar
- Best way to clean a concrete patio using algae cleaner
- Getting a pressure washer
- Best way to clean a concrete patio with a pressure washer
- Pressure washing concrete pavers
- Is a pressure washer worth the cost?
- These posts are good too
Concrete is a porous material so stains like grease and oil can penetrate the concrete making them difficult to remove. The good news is that there is a way to get your concrete looking almost as good as new.
I shoot quite a few photos and videos on the patio and it got to the point where I was so embarrassed about the state of the concrete patio that I started putting a drop cloth underneath my furniture upcycles so you couldn't see the floor stains in the pics!
You can see in the photo below how the concrete patio looked before cleaning. The photo is from my post 'How to whitewash a pinewood table'.
This year, we're redesigning our garden and the patio is moving to a different area.
Because the original patio stones were in such bad condition, we thought we could use them up around the garden somehow and buy new ones for the patio.
From this point on, we stopped pulling up the weeds and grass that sprouted up between the patio stones because we would be lifting the stones soon anyway.
By the time we came to clean the concrete patio, we had moss, grass, and weeds all over the place. Needless to say, our patio was not a pretty sight!
Patio cleaning without damaging the grass
We still wanted to have a go at cleaning the old patio stones first before moving them. That's when we started scouring the internet for the best way to clean a concrete patio and we came up with a few solutions to try.
Concrete cleaning methods
Most of the resources I looked at recommended similar advice for cleaning concrete patios and floors. The cleaning methods varied from using a pressure washer and harmless solutions like vinegar and baking soda to harsh chemical cleaners like trisodium phosphate, muriatic acid, or oxygen bleach.
Cleaning concrete - environmentally friendly
A major consideration for us was the environmental effect that the concrete cleaning solutions would have on the surrounding planted areas, grass, and wildlife. That's why we decided to try out the most natural concrete cleaning solution first.
Testing concrete cleaning methods
We also decided to test a small area at a time with each of the concrete cleaning solutions before going all out with the solution that worked best.
I'm sorry that I didn't get photos of the earlier processes because I hadn't intended on writing about this project on the blog. It just goes to show how little faith I had that we could make anything of the old patio. How wrong I was!
The preparation is the same for all of the concrete cleaning methods we tried so I'll deal with that first before getting into the nitty-gritty of each of the patio cleaning solutions we tried.
Preparing to clean a concrete patio
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Supplies you'll need
- Clear the patio of all furniture, potted plants, and accessories.
- Cut back any overhanging plants so that you have a clear view of the patio.
- Use a weeding knife to remove moss, grass, and weeds that may have grown up between concrete patio slabs and pavers.
- Brush away dirt, leaves, and loose debris using a stiff outdoor brush. If you are working on a large area, you may find it easier to use a leaf blower or outdoor vacuum cleaner for this.
- Spray the concrete patio down with a garden hose.
Once the surface dirt and leaves have been cleared away, you will be able to get a better look at your patio and see what type of stains you're dealing with.
For us, our biggest concern was removing the algae and mold stains on the patio so we decided to tackle those first.
Best way to clean a concrete patio with baking soda
We started with the most eco-friendly option of cleaning concrete which was the baking soda, and water method.
Supplies you'll need
- Equal parts water and baking soda
- Spray bottle
- Scrubbing brush
How it works
Mix equal parts of baking soda and water in a spray bottle. Some people will tell you to add a drop of liquid dish detergent, laundry detergent, or Castile soap to the mix which we opted not to do.
Working over small areas, spray the concrete patio stones with the baking soda/water mixture. You have to make sure you douse the concrete so that the area is soaked with the cleaning solution. (It should leave puddles on the surface).
Let the cleaning solution sit on the concrete floor or patio for around thirty minutes.
After thirty minutes, use a scrubbing brush or deck brush to work the mild cleaning solution into the concrete patio stones.
Hose the patio down with clean water.
The result of cleaning concrete with baking soda
You need to use quite a bit of elbow grease. It was hard work scrubbing the patio with a scrubbing brush, even though I used a scrub brush with a long handle to save my back!
Our concrete patio stones were slightly cleaner than when we started. The stubborn grease stains and mold were still there and the slabs were a long way from being clean.
Best way to clean a concrete patio with vinegar
Next, we decided to try the vinegar method of cleaning concrete. I use vinegar cleaner a lot for cleaning at home so I was looking forward to trying out this method on our concrete patio. I love that vinegar is a non-toxic, natural cleaner and that it's so versatile.
You should see how sparkling clean my chrome and stainless steel elements come up after I've cleaned them with vinegar cleaner, it's amazing!
Supplies you'll need
- White vinegar or cleaning vinegar
- Clean water
- Scrubbing brush with a long handle (natural or nylon bristles)
How it works
The cleaning process is the same as for the baking soda method above except for the waiting time.
If your concrete patio is unfinished, you can leave the vinegar solution to sit for around thirty minutes. If you are cleaning finished concrete, you should only let the solution sit for between five and ten minutes.
TIP: I've only ever used vinegar cleaner outdoors on my unfinished concrete patio, never on indoor concrete floors or surfaces. Vinegar is an acidic cleaner and may not be suitable for cleaning other types of concrete-like polished concrete. Always read the labels or check with the manufacturer if you are unsure.
The result of cleaning concrete with vinegar
It was still hard going, scrubbing the concrete patio stones with the vinegar solution but we did get a better result. We found that most of the grease stains were gone and the stones looked a lot lighter once they were dry. The only problem was that the mold and algae were still there, blah!
Best way to clean a concrete patio using algae cleaner
As a last resort, we decided to try a special purpose algae cleaner (borrowed from a friend).
Even though we were dealing with tough stains, I didn't want to go down the route of using muriatic acid, chlorine bleach, or oxalic acid so an algae stain remover seemed like the best way to go.
A commercial cleaner should always be a last resort. Even though it's not as aggressive as some other chemical cleaners like bleach, it's still recommended to wear a breathing mask and eye protection when using algae cleaner.
Supplies for using algae cleaner on concrete
How it works
Our algae remover was in a spray container and the first thing we did was to shake it well before spraying our test patch of concrete. The instructions said to leave the solution on the concrete for at least twenty-four hours so that's what we did. (If it rains during the twenty-four hours, you have to start again).
After twenty-four hours, we scrubbed the concrete with a scrubbing brush as per the instructions and then washed it down with clean water.
The result of cleaning concrete with algae cleaner
The algae cleaner did remove some of the algae but there was still a lot left behind. To be fair, the instructions recommended repeating the process a couple more times until all the algae disappeared. We just weren't happy with spraying our whole patio with dangerous chemicals multiple times just to get these old patio stones clean.
Getting a pressure washer
At this point, we decided we were probably going to have to give up on ever getting the patio stones clean at all. Then last Fall, the mister came home with something he swore he'd never buy. A power washer! It was on sale he said, calling his name he said. Hmm, I know that saying from somewhere haha!
Well, of course, he couldn't wait to try out the new pressure washer on the old patio stones, could he? He was so excited to test it that he pulled it straight out of the box and didn't even bother correcting the nozzle attachment on the sprayer! (The standard Vario nozzle has a wide jet for large surfaces).
As soon as I saw how those concrete stains were being zapped, I grabbed my boots and phone and started filming. I couldn't believe my eyes! All the time we had spent scrubbing this old concrete patio with all the different cleaning methods now seemed like a complete waste of our time.
In case you were wondering, I was not paid to write this post. I'm just giving my honest opinion of the best way to clean a concrete patio how we see it.
Best way to clean a concrete patio with a pressure washer
I have to say, the pressure washer was a complete game-changer. The paint stains, grease stains, mold, and all other types of stains completely disappeared after power washing.
I'm not sure if this would work on all types of concrete flooring but we did try it out on our concrete garage floor and had the same success there too.
I should point out here that we do not have any type of concrete sealant on our garage floor. The exterior concrete in the garage is going to be tiled eventually. We just wanted to try out the pressure washer on the garage floor to see if it would remove the oil and grease stains.
Pressure washing concrete pavers
This week, we tried out the pressure washer on the concrete patio at my parents in Law's place.
The patio had algae and mold spots in some areas which were completely removed by the pressure washer.
There were a few small oil stains on the patio which we were not able to remove with the power washer. You can see the before and after photos below.
Without a doubt, the pressure washer has to be one of the best cleaners for cleaning cement floors!
Supplies for pressure washing concrete
How to power-wash a concrete patio
Step one: Assemble the power washer according to the instructions.
Step two: Attach the power washer to the water supply (hosepipe). Use the fan nozzle attachment for large areas if there is one.
Step three: Make sure you are wearing rubber boots or working shoes and protective goggles.
Step four: Work on small areas at a time, holding the nozzle at least 12” away from the concrete to avoid damaging the surface.
Step five: Use a push broom to brush away excess water.
Step six: Refill any gaps around the patio slabs with sand.
Although using a pressure washer is the quickest and easiest way to deal with a stained area of your concrete patio there could be drawbacks to using this method if you get it wrong.
A word of caution: Pressure cleaners can be dangerous if they are not operated correctly! The jet must never be directed at people, animals, or electric equipment connected to the power supply or against the actual pressure cleaner.
Pressure washing concrete patio slabs can wear away at the surface causing it to deteriorate over time. Concrete deterioration usually happens when the pressure of the washer is set too high or by holding the nozzle too close to the surface (Should be at least 12" away). For best results, you should always follow the manufacturer's instructions.
Our pressure washer is designed for use with a ph-neutral cleaner based on a biologically decomposable anionic tenside. We didn't try this option because we found using water was enough.
According to the instructions, our pressure washer can be used to clean machines, vehicles, buildings, work tools, facades, terraces, gardening tools, etc.
So far, we've tried out our pressure washer on our concrete patio slabs, a few stains on our garage floor and my parent's in law's patio and it's been worth the purchase! You will never need to employ concrete cleaning services with special equipment if you have one of these compact little pressure washers tucked away at home.
Baking soda concrete cleaning method
The method of cleaning concrete with baking soda would work if the concrete wasn't very dirty in the first place. This method might also work on stains if you catch them straight away too. The baking soda method certainly was not the best way to clean a concrete patio in our opinion.
Vinegar concrete cleaning method
The vinegar cleaning method may be a good option for cleaning grease stains from concrete floors around the grill area or outdoor table after barbecuing. If you have an issue with mold on your concrete patio, vinegar cleaner is not much help. Now that our patio has been thoroughly cleaned with the pressure washer, I may try cleaning it with vinegar at the end of the year to remove grease stains.
Algae remover for concrete
The specialized algae remover will probably work if you use it enough times. The trade-off is that you are washing strong chemicals into the ground where you live. Keeping to best practices such as routine cleaning with vinegar once a year and spot cleaning for food stains after grilling would bring the best results.
Pressure washing concrete
For us, pressure washing was the best method for dealing with the dirt and stains on our high traffic patio area. As long as we use it properly (ie keeping the nozzle the correct distance away from the concrete and making sure to use the correct pressure), I think a good clean with the pressure washer once a year will keep the patio slabs looking great.
Is a pressure washer worth the cost?
I am amazed at the difference the pressure washer made on our patio. I'm so happy that we tried this first before dumping the slabs and buying new ones.
Although we had to pay for the pressure washer in the first place, it's a fraction of the cost compared to replacing the patio. We will also be able to put the pressure washer to good use in the future. For us, using a pressure washer is hands down the best way to clean a concrete patio and definitely worth the cost!
I hope you found this post helpful, let me know in the comments below what you think. Have you tried using a pressure washer before? What do you use yours for?
Also, if you have any ideas on the best way to clean a concrete patio without using a pressure washer, I'd love to hear those too!
(This post is not sponsored).
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