Written by Terry Smith

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UK’s best patio cleaner to kill algae, moss, and remove oil stains used in conjunction with pressure washers

This article was last updated on April 23rd, 2022 at 5:43 am

Following on from the patio sealer and patio grouts I just updated (very worthwhile taking a look – it may be pointless to clean your patio without those steps too), I thought it would make sense to check in and update the best patio cleaner as well! If your patio is in great nick, clear of weeds, but just a bit dirty or there some Algae growth (or moss) then you’ve arrived at the right place for advice – so let’s talk about what patio cleaners are and what they can do with some practical examples of what to use and where.

Image credit: Gani Khan – Patio cleaner

Patio cleaners come with a variety of key uses; some are best at algae removal, others killing moss and there are plenty that are a combination of both and it’s definitely important to understand the difference, if you’re looking for a good old fashioned filth and grease remover than you may want to look at pressure washer detergents too. In amongst those three main components you’ll find some patio cleaners that’ll handle the lot, but if I’m honest, picking one that specialised for each is far more viable and if you read my what you need to know about patio cleaners section then this will become perfectly clear and you’ll avoid being online complaining that you still have a knackered patio after a week after application! 😀 So whats the best way to clean your patio?

Best patio cleaner overall: Patio Magic Patio Cleaner 5L

Budget pick: Patio Magic! Concentrate – cheaper without the spray gun

Best patio cleaner for pressure washers: Kärcher 5 L Canister Pressure Washer Detergent, Universal Cleaner

Best patio cleaner for Algae: Patio Magic Patio Cleaner 5L

Best block paving cleaner for moss: SmartSeal Moss Killer

What you need to know about patio cleaners

Did you know Patio Magic, my top pick, is absolutely useless on dirt and grime build up? Well that’s because there are specialised best cleaners for each of the three main issues. There’s also some formulas that are specifically designed for the use in combination with pressure washers and those that are effective without any machinery, just a bit of scrubbing. So let’s take a closer look at what you might need.

What are the different types of patio cleaner?

As I mentioned there are three main types of patio cleaner that all do a specific job:

  • Removing dirt and oil
  • Killing Moss
  • Removing Algae

Whilst the Algae and moss do go hand in hand and will work on each other, products specialised for biological removal will have absolutely zero impact on dirt. Yep! A bit of a minefield. So let’s break it down a bit:

Dirt, oil, and stain removal

This is the type of cleaner that can lift oil. It’s basically designed to get underneath, in the porous stone, and lift out of the little crevices. there are two different types though. The Kärcher works great in combination with a pressure washer, whilst Pro-Kleen Patio and Driveway Cleaner is essentially a more powerful formula that can help break down and remove oil without a pressure washer – this doesn’t mean you can just sit and watch – the effects are limited – it will still need a good bit of elbow grease to get the dirt stains lifted. However, it is effective, no question on that. It’ll also go a little way to killing Algae too which is a nice and unexpected bonus (after everything I’ve said about being specialised) though it’s really slow to do so.

Clean down your patio properly with a petrol pressure washer if you have one

Moss Killer

Unfortunately for me I have a lot of experience removing moss 😀 Mainly from roofs but also from between cobble stones and block paving. One it starts to take hold it’ll pull all of the sand from your joints and result in needing to go right from the beginning with new jointing compound (patio grout) and a sealer. This isn’t cheap by the way, so it’s much better to catch this before the problem is too sever – and every time I have no hesitation recommending SmartSeal Moss Killer. I’ve personally used this to great effect and literally saved brittle clay tiles as a result of this product.

Algae remover

There are loads of different Algae removers but the one for patios that’ll keep coming up as you research is Patio Magic. Whilst it can handle Algae pretty easily, Blackspot and Lichen that have taken hold will almost certainly need a good bit of scrubbing to get out entirely – that or the use of a pressure washer will do the job so long as it’s plenty powerful.

How to use patio cleaner?

Luckily this one is super easy and doesn’t require a lengthy read – Some are completely ready to go like the Patio Magic. You just throw in a couple of batteries and the sprayer does the rest. With all the other options you’ll need to dilute the concentrate and then ideally use a watering can or garden sprayer to lay it on but there are a couple of considerations:

Practical example of what I would use:

With this I would use Patio Magic first and see how it comes up – it’s actually hard to tell if that’s just Algae or dirt as well. But the best place to start though is good old Patio Magic with this one:

Patio needs Patio Magic and maybe Kärcher washing detergent after

This one below looks a bit more dirty than a biological problem and it’s been like it for ages. If you’ve inherited this kind of patio or left it that long you’re going to want to look at either Kärcher with a pressure washer or Pro-Kleen Patio and Driveway Cleaner which will probably do a fair bit more for you (assuming you don’t have a pressure washer):

Patio dirt build up will benefit from Kärcher or Pro-Kleen Patio and Driveway Cleaner

If you’ve got moss building up around your block paving then a good shout is SmartSealHere’s a good example of where I would use it on block paving:

Moss build up going to want SmartSeal

This is where I’d use a moss killer like SmartSeal but I warn, it may need patio grouting (sand) again as the seal is broken – therefore it obviously needs sealing again once cleaned!

Hopefully that helps clear up the different types of patio cleaner you’ll want to use

Make sure it’s bone dry

Don’t try to do this if it’s damp at all. You really need a dry run and the surface needs to be thoroughly dry before application or it simply won’t take and work. Also, keep an eye on the weather for the next couple of days too – if there’s any rain in sight, postpone. It takes almost all of the products a couple of days to do the maximum damage to Algae and Moss and if it rains on them before, you will pretty much be wasting your time.

Some are toxic so wear PPE

Many of the best picks are toxic – hardly surprising with the grease and algae they are shifting and killer. The Patio Magic top pick is a prime example. If you take the letter of the law from the government with regards to cleaning they will tell you to wear gloves, aprons, and wellington boots. Do not, and I repeat, do not breathe this formula in, it’s designed to breakdown biological entities – what do you think happens to the lungs? 🙂 So yeah, normally I am not so much of a wet drip but this time I actually would advocate jeans, wellies, and gloves. Take your PPE seriously on this one!

Good old patio magic. It’s just such a brilliant allrounder – so it deserves it’s spot as best all round patio cleaner in my mind. The fact it made top pick for algae removal for patios in my other review says it all. If you follow the link you can get the full review there. I can’t see the value repeating the same thing so instead I’ll summarise it for you here:

Make sure when you lay this down, your patio is bone dry and have a decent spell of warm weather coming. Rain or surface water will significantly reduce the effectiveness of this. Please follow that point carefully – your flower bed or worse, pond won’t thank you for surface water running off with Algicide in it!

If this has got black spot or lichen and it’s really taken hold, there’s every possibility this will struggle. I’d have the petrol pressure washer of mine out on that for sure. Any excuse! 🙂 You can of course just use a scrubbing brush – either way will skin the cat so to speak.

Spray it on with the gun provided – you need a couple of AA batteries and that’s it – shoot! The good thing is once you have it you can just by the concentrate form and top up – that or use a garden sprayer and avoid the cost altogether saving a few quid!

Just like my SmartSeal pick, this is biodegradable so no worries for kids and pets once it’s dry which will take less than a day – so obviously be ready for any good run of weather. Here’s a look at what you can legitimately expect from Patio Magic:

Patio Magic Patio Cleaner 2.5L Refill

Not bad at all – I normally don’t like fancy name brands but this one is a thumbs up!


  • Great for Algae on patios
  • Easy to spray and no mess with the self contained sprayer unit
  • Only takes a day to see visible results


  • Not the absolute strongest – will struggle with lichen and blackspot if taken hold.

Smartseal are really on the ball when it comes to patios, cleaning, sealing, and maintaining. It’s probably no surprise that I used their product to rid myself of moss on my roof. This however was a delicate roof and I needed a moss killer that really killed moss – so after doing my research, how glad I was that I used it. In a day or so the moss started browning and falling away. If you’ve got moss all around your cobble stones or block paving this is a big thumbs up.

I hardly see the point writing the same thing – you can read the full review with pictures and process of that roof that I removed the moss here. The key takeaways for me were this really works, I used it again after I cleaned up by spraying a second coat and for 6 months my roof is still clear so you can expect exactly the same on your patio.

It took about a day for the moss to start dying – it turned brown pretty quick but what was interesting as I alluded to before, the top left took took longer to brown – did I not apply enough because of the awkward reach – I was struggling and the side closest to the window I applied from inside so much easier? 🤔 Here’s a close up look of that:

Moss died at the bottom first when using SmartSeal

The Ivy was long dead, I cut that and let it rot – the only way to avoid pulling all those tiles down! It all turned brown after a few days though so no worries on that.

You can go for a 1 to 5 if it’s not particularly taken hold – I would definitely do stronger and less diluted if you’ve got thick healthy moss on your patio though, why make life difficult for a few quid and it’s not active when it dries so no worries for the kids or pets – again to remind you it must be dry to be safe!

The best way to buy this is in bulk – it’s designed for commercial use, so you’re getting a bargain as well. Bonus!


  • Really kills moss off patios quickly
  • Took me personally a day to start seeing results
  • Commercial quality


  • Only value bought in bulk

This Kärcher 5 L Canister Pressure Washer Detergent is basically just the ticket if you’ve got dirty stains – not biological ones – so for example the trucks leaked oil, you’ve got dirt stains from the wheels coming on and off the drive, or birds and cats doing their business on your patio. I’ve actually already thoroughly reviewed this on best pressure washer detergents so not much point going into detail here – you can follow the link for a fuller description – this is the one I use with my petrol pressure washer and cordless pressure washer.

They call it gentle but I’m not sure why – I think it’s great at removing oil. The gentle is to relax you into using it on other less durable surfaces. I tested it on wooden garden furniture to great effect.

No joke, the biggest problem you’ll have is getting the lid off – it sounds trivial but I had to get a cloth and really go at it – I wonder if I just got a particular batch with a tight seal around the lid that wasn’t perforated properly. 


  • Great at pulling oil out of porous stone
  • Good all round dirt cleaner
  • Decent value for money


  • Lid welded on, literally!

Are you struggling to remove algae and mould growth from your patio? No worries, because you have Patio Magic to help you out. This is basically the same as the spray bottle version but the money off is a bonus.

This is a concentrated solution which has been specifically designed for the easy treatment and removal of mould and algae from hard surfaces. It is also very effective in preventing the growth of algae and mould.

The product also acts as an anti-bacterial disinfectant and has a long-lasting effect. When using this product, you don’t have to deal with tiresome scrubbing or pressure washing. Talking of pressure washing, there are some fantastic offers on electric pressure washers at the moment. All you need to do is just dilute the product in water, apply and then leave it to dry.

The product is so effective that it can last for months. Not just that, but it can treat up to 85 m2. One of the good things about the product is that it is also suitable to use indoors. In fact, you can even use the product as a pre-paint fungicidal wash.

This is a biodegradable product and thus, completely safe to use. In fact, it is also safe for both children and pets. You don’t have to exclude them while cleaning your patio using this product.


  • A single bottle of Patio Magic contains 2.5 litres of concentrated Patio Magic.
  • Concentrated solution effective for killing and removing algae and mould.
  • Leaves a long-lasting effect.
  • Suitable for hard surfaces.
  • Biodegradable product and inactive once dry
  • Safe for children and pets once it dries


  • Not designed for oil or dirt stains.
  • Will struggle with some Lichen / Blackspot

Patio Magic Patio Cleaner 2.5L Refill

The growth of moss and algae in your patio and garden can be very much annoying. It ruins the complete look of your paths and driveways. However, Pro-Kleen is in direct competition with good old Patio Magicand costs a fair chunk of change more. And if I’m honest, I don’t feel like you have much of an edge over Patio Magic though it is good.

The formula specifies it’ll give you 6 months of resistance after application too – I have to say with Algae it works great – many who have bought this and found problems are trying to do the wrong thing. This isn’t for dirt build up or grease – it’s for Algae, lichen, and will do a bit of damage to moss on your patio too.

Normally, just like Patio magic, this will start to dry up and be good to go in about a day or two – obviously the usual tricks apply – make sure you’ve got a weather break and it really is dry


  • Highly concentrated product.
  • Deliver you quick results.
  • Effectively kill and remove algae and mould.
  • Suitable for cleaning all types of outdoor hard surfaces.
  • Prevents the growth of algae and mould for up to 6 months.
  • Safe for children and pets.


  • Dont use this for dirt stains – a total waste of time

A far better contender for the best patio cleaner for grime than the HG Cleaner to rival the Kärcher is the Pro-Kleen Patio and Driveway Cleaner. his concentrated solution is designed to deep clean your outdoor areas. The solution is pretty strong and definitely matches the power of the Karcher with regards to lifting oil. But where it scores, it can also kill algae and mould too – though a lot slower than the specialised PatioIt makes it one of the only genuine all round patio cleaners that can dispose of dirt and oily streaks as well as the biological side of things too.

Applying this product is pretty straight forward. You can either use a watering can or a pump sprayer.


  • It’ll handle dirt and Algae – a nice plus
  • Works on almost all stone surfaces.
  • Straight forward application methods.

This is a concentrated patio cleaner for effective cleaning of garden tiles and patio stones. The product has received good reviews from people who have used it and I have to say HG make some incredible chemical products the HG Duo drain unblocker being one! It’s pretty much ideal for dirt and oil stains – I’d probably say it’s more concentrated than the Kärcher but there’s a lot less product so I would still take the Kärcher.

Realistically the best application of this is for heavy staining on slabs – it does a pretty decent job of pulling off grime and dirt that’s caked in but I have to say, for all the effort of applying, scrubbing and cleaning down after a good old pressure washer does exactly the same thing – assuming it’s a powerful model of course. It’s a good buy but I still prefer the Kärcher.


  • Strong and concentrated formula ideal for heavier staining
  • Suitable for all types of hard surfaces.


  • Kärcher a better pick for staining in my mind.

Final thoughts

Finding the best patio cleaner is relevant to almost every single home in the UK. The patio area is one of the best places to be on a long summer evening with a nice barbecue and patio heater to keep the chill off as it gets late. Nice garden lighting adds to the relaxed ambience. The next morning we see the mess and can’t get the garden and patio cleaned up fast enough. First comes the clear up then out with the pressure washer or broom and cleaning solution. The best patio cleaner should be strong enough to breakdown grease and dirty in conjunction with a pressure washer, taking away all the hard elbow grease. It should be as child and pet friendly as possible, and fairly priced, so with that in mind I have picked the best patio cleaners to save you time – Patio magic, SmartSeal, and Karcher have you covered.

And remember – keeping your patio clean is important, it solves longer term problems like removing grout and sealing again and again!

About Terry Smith

I’m Terry Smith from gardentoolbox.co.uk, a professional landscape designer, hobbyist gardener, and barbecue fanatic with 20 years experience building and restoring. So as you go through my site you'll watch me document some of the professional garden installs I make as well as the major projects I take on at home. While sharing those experiences and guiding you, I'll be recommending some great tools I use to enable this along the way so you can really buy in confidence. Always feel free to pop me a message: info@gardentoolbox.co.uk

View all posts by Terry Smith

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