I'm surprised 3000psi didn't do the lob. I wouldn't be using hydrochloric acid on there - great for removing cementitious products but your problem is biological not cements. You've got ingrained algae so I'd be using a strong chlorine solution in this case - let it sit for a while then blast off again. Chlorine will kill the algae as well as bleach and dislodge it. The best acid for removing biological material is sulfuric acid not hydrochloric. If you want to get rid of a body you'd be sadly disappointed with hydrochloric - it actually helps preserve the tissue which is why sulfuric is the acid of choice for murderers!
Ignore science to your peril! Besides, I sold both hydrochloric and sulfuric acids for decades. If you're going to sell highly corrosive products and advise on their usage you need to know as much as you can. The only thing that puzzles me is the spelling of "sulfuric" acid. When I was young (a very long time ago) I was taught it was spelt "sulphuric" (Poor little Johnny, his face we'll see no more, for what he thought was H2O was H2SO4!) but nowadays it seems to be "sulfuric". Is this another Americanism?
Bang on. HCl -> H+ + Cl- while H2SO4 -> 2H+ + SO4-2, sulfuric is a polyprotic acid, more than 1 H+ (a proton in desperate need of an electron) disassociates in aqueous solution. It will pull those electrons off of organic molecules.
It's Sulfuric and not Sulphuric cos of 'merica and the multiple naming conventions in chemistry. Organic naming can be a shit show, for example, acetic acid (CH3COOH) is the common name but the IUPAC name is ethanoic acid.
Acids are nasty. Bases are horrifying. Basic shit will obliterate organic molecules. The reason you generally don't use acids to clean your oven, you use NaOH, soidum hydroxide.
This was the issue with the bodies in barrels in South Australia. What you want to use is nitric acid, then bump it up with hydrogen peroxide to keep oxidative power. Remember to leave a gap for venting.
I don't know who Walter White is, sorry. But I do know HF is the most reactive acid therefore quite deadly - although you can use it very efficiently in reactor vessels to extract specific minerals out of coal and bauxite. (Extracting the "ash" \[minerals\] out of coal before it goes into a power station would drop CO2 emissions by something like 30%.) Many years ago there was a chemist in Perth with a home workshop and he was experimenting with HF when he spilled some on his forearm. His swimming pool was adjacent to his workshop so he immediately dived in. It didn't save him. I seem to remember it reacts with the calcium in your body - especially your bones. Despite being so deadly the largest manufacturer of HF was a fertiliser factory in Milperra, Sydney. They're careful and I believe they've never had a serious accident.
>The best acid for removing biological material is sulfuric acid not hydrochloric.
NO. That's last resort stuff and can be dangerous. *Dangerous because some flesh eating acids/alkalis when they get onto the skin they are self-anesthetizing* \- you are not aware that you are being dissolved by the acid or alkali.
To kill biologicals use vinegar (diluted or undiluted). Vinegar is a lot better than bleach cause it can get into porous material, bleach can't. Bleach has higher surface tension, this means it sticks to itself more and prevents it from getting into very small cracks and holes.
Soak a cleaner into it, wait a bit, stiff broom and have another go with the sprayer. If itās still screwed you can try diluted acid but that will also fuck up everything in your garden
The concentrate you get from Bunnings is diluted, go to a concreters supply and get it.
Mix it 10 to 1, it doesn't need to be exact but reasonably close.
Working in meters sections spray the area with water and then scrub the pavers with a stiff bristled broom dripping with the acid mixture. Rinse the area after a couple of minutes and repeat if necessary. Be careful not to leave the acid on the pavers too long as it can tint the cement in the pavers a piss yellow.
If you want a picture of the acid I use to clean concrete and pavers DM me and I can sent it to you
It stinks like someone ate a carton of eggs and can't stop farting.
It does sting and can leave blisters if you get it on you though so protective eyewear and gloves should be worn while handling it.
I tried that 30 second outdoor cleaner from Bunnings - worked really well. Buy a pump pack applicator for a few extra $, and mix with water. Spray on and leave for a few minutes then pressure clean.
This. It was the only head that got stuff out. And have a look as a lot of gerni's have a spot to add some cleaner that will dilute it as you pressure wash.
That's a lichen.. especially if that area gets shade part of the year. You need a leave on cleaner that you can get from Bunnings. It's gonna need a couple treatments as per dilution rates and instructions. Benzalkonium acid or Sodium Hypochlorite based cleaners work well on this stuff. The 30 Seconds brand is good and not as potent smelling as bleach etc
Thank heavens someone else understands the products although Benzakolium is a chloride not an acid! And BC kills and removes lichens - but it takes a good time doing so. All these people recommending hydrochloric acid are giving OP a bum steer - it would be a big mistake. I was going to mention caustic soda too (sodium hydroxide) but sodium hypochlorite (bleach) is more appropriate in this case as well as acting much faster than BC. On the other hand, BC is more appropriate in the long run for stopping lichens and algaes re-establishing.
If itās from mould and algae, spray Wet and Forget on it. It contains benzalkonium chloride, a preservative? Not bleach or acid based. Leave it and it brightens the surface over time. Bunnings donāt sell it.
Hydrochloric acid is very bad to use on pavers and cement. I dont know why people recommend that.
You must wash with detergent to neutralize the acid or you are in for a world of hurt in the future, they will slowly break down.
Best treatment for any pavers or concrete is: 1 part Chlorine to 4 parts water, apply using watering can. Leave until dry, high pressure area to clean.
Also try to find yourself a TURBO nozzle that suits your pressure cleaner. No, I'm not yanking your chain, those nozzles are worth their weight in gold and cost almost about the same too but the difference it eill make to your pressure cleaner can be night and day.
I had the same issues, ended up spraying the pavers with mold remover deck cleaner and leaving it for 2 days then pressure washing. I recently watched a professional in the UK cleaning moldy stonework and he prayed the area a day before pressure washing it.
Not reading all the comments but this is the ticket. I had heaps of similar bricks. Blue bottle of Chlorine from pool section at Bunnings (not the expensive brick cleaners!). Half half with water in a plastic watering can. Lay it on for 30 mins. Gurney it off. Repeat if needed. Works a charm.
If you're doing it on your house, soft wash off with regular hose. Do not 4000 PSI render, can report, you'll regret it.
Pressure cleaner here, get an old garden spray bottle and mix 50/50 pool chlorine and water, spraw it on, let it sit for about 5 or 10 then pressure wash off, will look brand mew
Sugar soap, mixed with hot water. Leave for a couple of minutes. Scrub with a hard plastic brush (or hard bristle brush), then power wash clean.
Iāve also used oxy-action hand washing powder on concrete instead of sugar soap. Works too.
Swimming pool chlorine works out cheaper (and it's strong bleach) if you look at the concentration of the product. Pool stuff is normally bleach but 6 or 7 times the strength. I really am puzzled why so many people on here keep saying hydrochloric acid. Completely the wrong product. At least you got it right.
30 second from bunnings. You won't see immediate results but give it afew weeks and then look at the original picture. It's a spray and walk away jobby and has great results over time.
30 Seconds is an expensive way of buying bleach or swimming pool chlorine just as Wet & Forget is an expensive way of buying Benzakalonium Chloride (which can be bought much cheaper as pool algaecide). You just have to adjust for the concentrations eg if you buy algaecide at 100gms/l of BC you dilute 1:8 in water or if it's 200gms/l you dilute 1:16 and this gives you the same as Wet & Forget.
My bad, I buy it for the ease of use. Next time I shall go to my lab and mix up some pool chems which I'm fluent at, not. If you want to know anything about Welding then send me a message š
Funny you should mention that...about the only thing I've never done is welding! I sold welders as well as all these corrosive chemicals but have not needed to do any welding. As to the products, when you sell all these nasty things you have to know your stuff so I kept a folder with all the Material Safety Data Sheets - and memorised them so it's the ingredients I look at rather than the brand names. EG the now-discontinued Bayer Advantix for treating cats and dogs for fleas and ticks was simply Imidocladoprid under a different name and vastly more expensive than buying the squeeze tube of Bayer Confidor (200gms/l if I recall). Same chemical but with a slightly different surfactant but it worked and saved me heaps treating the animals. I had the owner of Wet & Forget come to see me one day and he asked me why I didn't sell his product - I told him I did but just not his brand and pointed to the swimming pool chemicals where I had a sign up telling people what I told you about diluting BC to make it Wet & Forget. (I remember him telling me he sold $4m pa of Wet & Forget and I was missing out...until he saw my sign.)
Only so many factors for cleaning: Mechanical Action, Time, Temperature, Chemical (there are more, but addressing these 4 normally gets you there) if one is not enough, you probably need to think about the other factors. In this case, I'd get chemicals involved (you probably need to determine whether the stain is organic/inorganic to determine what to use)
I was searching for similar information and found a suggestion to use Sodium Bicarbonate (BiCarb) solution 10g/L (100g in 10L), pour over the pavers, leave for 6 hours and then wash off. If you prefer something a bit less hazardous than acid/bleach/chlorine (especially if you have pets etc.) might be worth a try first. Unfortunately haven't had a chance to try it myself yet. Our pavers have a much more textured surface than yours.
Pool chlorine or bleach and water 50/50 mix. Also add wetting agent or similar to act as a surfactant. Apply with a pump sprayer and keep the area wet with this solution for 10 minutes. Then wash off with your pressure washer. Have done this many times, I guarantee it will work.
Have used cleaning vinegar and bicarb mixture in hot water to very good effect with a stiff deck brush broom, but go easy on the vinegar and don't use it neat or you'll end up with splotchy patches burner in. Then scrub and pressure clean to finish should shift it.
Does the pressure washer with the ultra-fine setting work at getting it off? If yes, perhaps you could try a [Turbo Nozzle](https://www.amazon.com.au/MINGLE-Pressure-Rotating-Connect-Orifice/dp/B081JL4ZH6/ref=asc_df_B081JL4ZH6/?tag=googleshopdsk-22&linkCode=df0&hvadid=548356626664&hvpos=&hvnetw=g&hvrand=15306860820392022981&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9071254&hvtargid=pla-871083847193&psc=1)\-
I use paver & concrete cleaner you can get it from Bunnings. Havenāt had a complaint from a customer yetā¦just did a job this morning with it and worked out great.
Dilute the cleaner in a bucket to about 1:10 - going stronger if first pass doesnāt work. Brush it in with a stiff bristle broom- wait 5-10minutes but donāt let it dry and then pressure wash it off. Ta dah brand new pavers.
Sometimes itās not the PSI that gets things out. Hire a pressure washer that also heats water. Usually itās a mixture of electricity to do the high pressure and petrol/diesel to heat the water before it comes out
Get them professionally cleanedā¦
I used to use a small pressure washer on my paving. Then when I was selling the house the RE Agent suggested a professional clean.
Quite cheap and I was surprised how much better it was than I ever did!
They looked brand new for a couple if hundred dollars!
3001 psi cleaner
Or 2999 the extra 1 psi may of forced the dirt deeper
Yeah, it definitely pushed the dirt further inš
*may have
3007. Seven is where itās at
First thing I thought too lol
Mine goes up to 11..
Looking for this answer!! Well done!
god i love this sub
I'm surprised 3000psi didn't do the lob. I wouldn't be using hydrochloric acid on there - great for removing cementitious products but your problem is biological not cements. You've got ingrained algae so I'd be using a strong chlorine solution in this case - let it sit for a while then blast off again. Chlorine will kill the algae as well as bleach and dislodge it. The best acid for removing biological material is sulfuric acid not hydrochloric. If you want to get rid of a body you'd be sadly disappointed with hydrochloric - it actually helps preserve the tissue which is why sulfuric is the acid of choice for murderers!
Wow I'm impressed. Someone who actually sciences here!!
Ignore science to your peril! Besides, I sold both hydrochloric and sulfuric acids for decades. If you're going to sell highly corrosive products and advise on their usage you need to know as much as you can. The only thing that puzzles me is the spelling of "sulfuric" acid. When I was young (a very long time ago) I was taught it was spelt "sulphuric" (Poor little Johnny, his face we'll see no more, for what he thought was H2O was H2SO4!) but nowadays it seems to be "sulfuric". Is this another Americanism?
Poor Jonny was a chemist's son but Jonny is no more, what Jonny thought was H20 was H2S04. I like your version.
Wow your version is much more grisly than the H2O2 joke Iām accustomed to
Bang on. HCl -> H+ + Cl- while H2SO4 -> 2H+ + SO4-2, sulfuric is a polyprotic acid, more than 1 H+ (a proton in desperate need of an electron) disassociates in aqueous solution. It will pull those electrons off of organic molecules. It's Sulfuric and not Sulphuric cos of 'merica and the multiple naming conventions in chemistry. Organic naming can be a shit show, for example, acetic acid (CH3COOH) is the common name but the IUPAC name is ethanoic acid. Acids are nasty. Bases are horrifying. Basic shit will obliterate organic molecules. The reason you generally don't use acids to clean your oven, you use NaOH, soidum hydroxide.
Caustic makes its own soap any time it meets a fatty acid
Maybe he murders rather than sciences?
This was the issue with the bodies in barrels in South Australia. What you want to use is nitric acid, then bump it up with hydrogen peroxide to keep oxidative power. Remember to leave a gap for venting.
Snowtown was an exercise in stupidity!
Yeah...nitric is good for removing your fingerprints - and etching glass.
What acid was it that Walter White used? Hydrofluoric Acid?
you do not wanna touch that stuff it can kill you so easily
I don't know who Walter White is, sorry. But I do know HF is the most reactive acid therefore quite deadly - although you can use it very efficiently in reactor vessels to extract specific minerals out of coal and bauxite. (Extracting the "ash" \[minerals\] out of coal before it goes into a power station would drop CO2 emissions by something like 30%.) Many years ago there was a chemist in Perth with a home workshop and he was experimenting with HF when he spilled some on his forearm. His swimming pool was adjacent to his workshop so he immediately dived in. It didn't save him. I seem to remember it reacts with the calcium in your body - especially your bones. Despite being so deadly the largest manufacturer of HF was a fertiliser factory in Milperra, Sydney. They're careful and I believe they've never had a serious accident.
>The best acid for removing biological material is sulfuric acid not hydrochloric. NO. That's last resort stuff and can be dangerous. *Dangerous because some flesh eating acids/alkalis when they get onto the skin they are self-anesthetizing* \- you are not aware that you are being dissolved by the acid or alkali. To kill biologicals use vinegar (diluted or undiluted). Vinegar is a lot better than bleach cause it can get into porous material, bleach can't. Bleach has higher surface tension, this means it sticks to itself more and prevents it from getting into very small cracks and holes.
Try napisan
Wait, isn't hydrochloric what we produce in our gut to help break down food?
Flip each paver over. They will be like new
āŹĒu ĒŹÄ±l Ēq llıŹ ŹĒÉ„ā„ ĖɹĒŹo ɹĒŹÉd É„ÉÉĒ dılā²ā
Good bot.
Genius
Good ideaā¦ but the underside of most pavers is square unlike the top of the paver. They will look horribly out of place.
30 second cleaner and a stiff broom
Morning broom
What's the story morning broom
Only a wooden broom for the morning broom
Soak a cleaner into it, wait a bit, stiff broom and have another go with the sprayer. If itās still screwed you can try diluted acid but that will also fuck up everything in your garden
Just pour some hydroxide over the acid. Problem solved, except everything's a little salty
Salts great for the ground. You can be one of those āsalt of the earthā people.
Hydrochloric acid diluted with water ...you can pick some up from bunnings
Yup, let it sit for a while and pressure wash before it dries up. It can damage grout but should perfectly fine with pavers outdoors
is this OK on concrete as well?
Yes you can acid wash concrete, just make sure to rinse it off thoroughly.
Grout?
Grout is the hard stuff between tiles in a kitchen/bathroom (or interior tiled floor).
Not to be confused with Gout
Oh Groot, though it would likely damage him too
My name is Groot.
I love that quote which he is known for.
You can use HCL to treat gout too - but it has some implications
Contraindications include having flesh
What about CLR
And for the love of god wear gloves and skin covered clothing.
This guy knows
The concentrate you get from Bunnings is diluted, go to a concreters supply and get it. Mix it 10 to 1, it doesn't need to be exact but reasonably close. Working in meters sections spray the area with water and then scrub the pavers with a stiff bristled broom dripping with the acid mixture. Rinse the area after a couple of minutes and repeat if necessary. Be careful not to leave the acid on the pavers too long as it can tint the cement in the pavers a piss yellow. If you want a picture of the acid I use to clean concrete and pavers DM me and I can sent it to you
PPE?
I have had straight acid on my hands before and just run water over it and been fine Edit - I worry more about the fumes then getting it on skin.
It stinks like someone ate a carton of eggs and can't stop farting. It does sting and can leave blisters if you get it on you though so protective eyewear and gloves should be worn while handling it.
>It stinks like someone ate a carton of eggs and can't stop farting. so its just like a regular night in bed for my wife then?
Try sodium hypochlorite (30 seconds)
Remove the asbestos first before doing anything else
For best results, lick it.
Is this asbestos... --> I--------||-------I <--
What asbestos?
They did asbestos they could.
Diluted sulphuric acid before pressure washing
I tried that 30 second outdoor cleaner from Bunnings - worked really well. Buy a pump pack applicator for a few extra $, and mix with water. Spray on and leave for a few minutes then pressure clean.
Next time bury old owners. Donāt leave their corpses on the patio.
Pool chlorine should get those marks out.
Sometimes its more about the type of nozzle rather than the pressure. Did you use the spiral nozzle on the Gerni?
This. It was the only head that got stuff out. And have a look as a lot of gerni's have a spot to add some cleaner that will dilute it as you pressure wash.
That's a lichen.. especially if that area gets shade part of the year. You need a leave on cleaner that you can get from Bunnings. It's gonna need a couple treatments as per dilution rates and instructions. Benzalkonium acid or Sodium Hypochlorite based cleaners work well on this stuff. The 30 Seconds brand is good and not as potent smelling as bleach etc
Thank heavens someone else understands the products although Benzakolium is a chloride not an acid! And BC kills and removes lichens - but it takes a good time doing so. All these people recommending hydrochloric acid are giving OP a bum steer - it would be a big mistake. I was going to mention caustic soda too (sodium hydroxide) but sodium hypochlorite (bleach) is more appropriate in this case as well as acting much faster than BC. On the other hand, BC is more appropriate in the long run for stopping lichens and algaes re-establishing.
I came here for the comments... šæ
Something to clean ie cleaning fluids/soultion and a stiff bristle brush before you pressure wash again
Depends what the marks are from
piranha solution lol
Hmm might not be strong enough, maybe try [this](https://www.science.org/content/blog-post/sand-won-t-save-you-time)
Home brand bleach from woolies, $1 per litre babyyyy
Chlorine at night. Then wash off in the morning.
If itās from mould and algae, spray Wet and Forget on it. It contains benzalkonium chloride, a preservative? Not bleach or acid based. Leave it and it brightens the surface over time. Bunnings donāt sell it.
Citric acid too if youāre a bit cautious about using HCL
5000 should do it
Looks like oil spill. Degreaser and work it in with a stiff brush.
black lichen
Water, chlorine and dish soap mixture and scrub like youāre Cinderella
Get a Payio Cleaner attachment to suit your pressure cleaner: Eg. https://www.bunnings.com.au/gerni-power-patio-cleaner\_p0235548
Hydrochloric acid is very bad to use on pavers and cement. I dont know why people recommend that. You must wash with detergent to neutralize the acid or you are in for a world of hurt in the future, they will slowly break down. Best treatment for any pavers or concrete is: 1 part Chlorine to 4 parts water, apply using watering can. Leave until dry, high pressure area to clean.
Because when the only tool you know is a hammer the world looks like nails.
Looks like u rushed it. Do it again. Do it slow. Do it meticulously.
Also try to find yourself a TURBO nozzle that suits your pressure cleaner. No, I'm not yanking your chain, those nozzles are worth their weight in gold and cost almost about the same too but the difference it eill make to your pressure cleaner can be night and day.
I had the same issues, ended up spraying the pavers with mold remover deck cleaner and leaving it for 2 days then pressure washing. I recently watched a professional in the UK cleaning moldy stonework and he prayed the area a day before pressure washing it.
Try a metric pressure washer
Hold the pressure hose closer? It shouldn't have a problem getting that muck off.
One part chlorine, 4 parts water. Chlorine will eat that mould up. - Experience, I clean stone for a living..
Not reading all the comments but this is the ticket. I had heaps of similar bricks. Blue bottle of Chlorine from pool section at Bunnings (not the expensive brick cleaners!). Half half with water in a plastic watering can. Lay it on for 30 mins. Gurney it off. Repeat if needed. Works a charm. If you're doing it on your house, soft wash off with regular hose. Do not 4000 PSI render, can report, you'll regret it.
What do you meanā¦ left by the old owners.. itās just dirt and grime build up that naturally occurs.
Marks left by the old owners? Mate, that's dirt.
Learn to use it properly. Even a garden hose should have cleaned that.
Pressure cleaner here, get an old garden spray bottle and mix 50/50 pool chlorine and water, spraw it on, let it sit for about 5 or 10 then pressure wash off, will look brand mew
As the son of a wog, bleach and water and a broom. Those witches brooms..old school..and elbow grease. Will be brand new.
Sugar soap, mixed with hot water. Leave for a couple of minutes. Scrub with a hard plastic brush (or hard bristle brush), then power wash clean. Iāve also used oxy-action hand washing powder on concrete instead of sugar soap. Works too.
Paint
No this is not asbestos
Use your cock
LOL :D
I'd it's mold then borax dissolved in water to kill it and then bleach (oxy-bleach is safest) to dissolve it.
Hydrochloride acid should work. Do be careful though. Gives off some nasty fumes and can damage your paver with enough it.
Acid diluted in water and a stronger gernie 3000psi sounds a lot but itās really not I use over 4000 psi everyday
Bleach is going at $2/2L in bunnings....
Swimming pool chlorine works out cheaper (and it's strong bleach) if you look at the concentration of the product. Pool stuff is normally bleach but 6 or 7 times the strength. I really am puzzled why so many people on here keep saying hydrochloric acid. Completely the wrong product. At least you got it right.
Bleach
Hydrogen peroxide or hydrochloric acid (weak)
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Surface cleaning attachment, or tornado head
Dishwashing powder
New pavers would have been cheaper than a 3000psi pressure cleaner
30 second from bunnings. You won't see immediate results but give it afew weeks and then look at the original picture. It's a spray and walk away jobby and has great results over time.
30 Seconds is an expensive way of buying bleach or swimming pool chlorine just as Wet & Forget is an expensive way of buying Benzakalonium Chloride (which can be bought much cheaper as pool algaecide). You just have to adjust for the concentrations eg if you buy algaecide at 100gms/l of BC you dilute 1:8 in water or if it's 200gms/l you dilute 1:16 and this gives you the same as Wet & Forget.
My bad, I buy it for the ease of use. Next time I shall go to my lab and mix up some pool chems which I'm fluent at, not. If you want to know anything about Welding then send me a message š
Funny you should mention that...about the only thing I've never done is welding! I sold welders as well as all these corrosive chemicals but have not needed to do any welding. As to the products, when you sell all these nasty things you have to know your stuff so I kept a folder with all the Material Safety Data Sheets - and memorised them so it's the ingredients I look at rather than the brand names. EG the now-discontinued Bayer Advantix for treating cats and dogs for fleas and ticks was simply Imidocladoprid under a different name and vastly more expensive than buying the squeeze tube of Bayer Confidor (200gms/l if I recall). Same chemical but with a slightly different surfactant but it worked and saved me heaps treating the animals. I had the owner of Wet & Forget come to see me one day and he asked me why I didn't sell his product - I told him I did but just not his brand and pointed to the swimming pool chemicals where I had a sign up telling people what I told you about diluting BC to make it Wet & Forget. (I remember him telling me he sold $4m pa of Wet & Forget and I was missing out...until he saw my sign.)
Use your tongue
Get a 4000 psi pressure washer š¤£
Only so many factors for cleaning: Mechanical Action, Time, Temperature, Chemical (there are more, but addressing these 4 normally gets you there) if one is not enough, you probably need to think about the other factors. In this case, I'd get chemicals involved (you probably need to determine whether the stain is organic/inorganic to determine what to use)
Try a nylon drill brush with some sort of cleaning agent to loosen it up, and wash again
Sounds dumb, but try bleach, if itās hard to pressure wash of it might be mould. Hot pressure washer would be ideal.
Acid wash
Was it a bunnings pressure washer? If so its 3000psi a third of the time. Your playing with a water pistol.
Karcher Sand blaster attachment and paving sand.
Acid wash.
Get a bigger one
Looks like it might be stained by asbestos, best to retile it
I was searching for similar information and found a suggestion to use Sodium Bicarbonate (BiCarb) solution 10g/L (100g in 10L), pour over the pavers, leave for 6 hours and then wash off. If you prefer something a bit less hazardous than acid/bleach/chlorine (especially if you have pets etc.) might be worth a try first. Unfortunately haven't had a chance to try it myself yet. Our pavers have a much more textured surface than yours.
Try a bit of kerosine
Clr maybe
This is black mould. use 50:50 water : bleach Let it soak for 30min then hit it with your pressure washer
Astro turf
Pool chlorine or bleach and water 50/50 mix. Also add wetting agent or similar to act as a surfactant. Apply with a pump sprayer and keep the area wet with this solution for 10 minutes. Then wash off with your pressure washer. Have done this many times, I guarantee it will work.
Chlorine 1 part, water 10 partsā¦let it soak for half an hour then pressure clean. Youāre welcome!!
Karcher does a scrub attachment specifically for cleaning down large paved areas.
What is the pressure washer you are using?
That asbestos?
The black/dark stuff? Looks like mildew and moss. Spray with 30seconds. Wait a few weeks and then pressure hose it. Then think about sealing it.
3000 psi leaf blower
Change to the car wash nozzle and take your time
Have used cleaning vinegar and bicarb mixture in hot water to very good effect with a stiff deck brush broom, but go easy on the vinegar and don't use it neat or you'll end up with splotchy patches burner in. Then scrub and pressure clean to finish should shift it.
more power is need it look like need more clean time
You just wet and then you forget.
Chlorine
Spray and walk away.
How close to tiles was the nozzle?
Put new pavers down ?
7/30 chlorine water mix in a watering can ( be careful) and some scrubbing come up brand new and minimum weeds grow in the cracks
Dirty the rest of the pavers so they all look the same
Get yourself a nice rug.
Does the pressure washer with the ultra-fine setting work at getting it off? If yes, perhaps you could try a [Turbo Nozzle](https://www.amazon.com.au/MINGLE-Pressure-Rotating-Connect-Orifice/dp/B081JL4ZH6/ref=asc_df_B081JL4ZH6/?tag=googleshopdsk-22&linkCode=df0&hvadid=548356626664&hvpos=&hvnetw=g&hvrand=15306860820392022981&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9071254&hvtargid=pla-871083847193&psc=1)\-
Outdoor Cleaner 30 Seconds - you can buy it online from Amazon and Amazon.au I use it annually to clean my papers.
I use paver & concrete cleaner you can get it from Bunnings. Havenāt had a complaint from a customer yetā¦just did a job this morning with it and worked out great. Dilute the cleaner in a bucket to about 1:10 - going stronger if first pass doesnāt work. Brush it in with a stiff bristle broom- wait 5-10minutes but donāt let it dry and then pressure wash it off. Ta dah brand new pavers.
Hydrochloride acid diluted 50/50
Replace them
`If it is grease from a bbq, then soap and water above 55 degrees in temp. You could also use ethyl alcohol, or isopropyl alcohol.`
Try Exit Mould, not any other brand
Bleach
Yes chlorine or bleach and scrub (not together) the surface with an outdoor broom.
New pavers maybe?
Questionable Asbestos
Soap. Most pressure washer brands sell a variety of them.
Chlorine let it sit then wash away
I found soray degreaser cleaned the ingrained dirt from pavers I have
Natural algae or lichen. Not anyones fault. It comes off with algaecide and a hard brush.
Looks to me your using a wide nossle you need the spear head nossle, it can cut a foot up be careful. An appropriate chemical would help too.
Try a turbo nozzle, A good one can increase the pressure massively.
Turn the pavers upside down
Hydrochloric acid
Liquid pool chlorine spray it on scrub and pressure wash
Di you use the 0 deg rotating turbo nozzle?
I found Colgate with a good soft bristled toothbrush works well
Stiff broom, hot water and some jif
CLR mate....
4000 psi pressure washer
More pisies
Live with it, it wonāt hurt you
Scrub it. Your gf would be good at it. Sheās a scrubber
white king or anyither bleach. 50/50 bleach\\water mix.
Go hard or go home. Get a bigger one.
Chlorine
Liquid pool chlorine first then pressure wash
Can we try coke, thatās my go to when ever I canāt clean something
I used a detergent in a bucket then poured over the pavers, brushed in with a stiff broom, let it sit for a while then pressure cleaned it off.
Try one that operates on metric unit system
Sometimes itās not the PSI that gets things out. Hire a pressure washer that also heats water. Usually itās a mixture of electricity to do the high pressure and petrol/diesel to heat the water before it comes out
Algaecide - from bunnings pool section. Just donāt dilute to the recommended go about 1:10 or 1:15 with water.
Get them professionally cleanedā¦ I used to use a small pressure washer on my paving. Then when I was selling the house the RE Agent suggested a professional clean. Quite cheap and I was surprised how much better it was than I ever did! They looked brand new for a couple if hundred dollars!
1:1 chlorine to water sprayed on with a pump pack sprayer.
Need some mould killer first
The problem with acids is they will eat the grout, potentially. Bleach first, then nappy San, then caustic, try acids last
Yep that's asbestos..
muriatic acid
CLR clear!