.... and now for something completely different.....

[chrisinplymouth]

As our 3 month trip down to Portugal is now off, I thought I’d get the garden into some sort of shape. I’ve pressure washed the slabs but been left with some sort of litchen marks.... see photo.... pressure washer won’t shift them nor neat bleach. Any suggestions welcome.
Tia Chris

 

[David and Sally]

Have you tried a turbo nozzle?

 

[Janine]

You can get something from the garden centre that you dilute and sprinkle on from a watering can.

 

[movan]

As our 3 month trip down to Portugal is now off, I thought I’d get the garden into some sort of shape. I’ve pressure washed the slabs but been left with some sort of litchen marks.... see photo.... pressure washer won’t shift them nor neat bleach. Any suggestions welcome.
Tia Chris
View attachment 370549

Are they slippy?

If not, I might be tempted to think 'they add character' but difficult to tell from photo.

 

[Jimbohorlicks]

You need some sodium hypochlorate, it's a very strong oxydising bleach that farmers use for shippons etc. You can buy it in 25 litre tubs from a farm supplies or similar, around £18 or so.
Dilute itx4 with water, brush on or spray but be careful its very strong and will bleach clothes quickly, that's if not all sold out due to CV.

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[rosalan]

I asked at our local garden centre. Although he has a spot on local radio, he did not seem to know. I would be interested to find out, including a few white spots. Will the sodium chlor. harm our cats?

 

[hymerman]

Why remove them, they all add to the natural look of the garden ?
I know that we're all different , but I think people use too may chemicals in their gardens , killing off all the natural stuff.

 

[robnchris]

Turn the slab over.

 

[old-mo]

They look like the marks you get when you prise a barnacle off a rock down the beach..

 

[GerTee]

Hi Chrisinplymouth, we had the exact same problem with our patio. We bought 10% sodium hypochlorite with Calgon from our local swimming pool supplier. Applied neat using a stiff broom and washed off after about 5 mins. Worked a treat. Just need to be careful with the washing off as it’s pretty nasty stuff. Again as per previous post only paid around £20 for 20l.

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[Nanniemate]

Close your eyes, I think it looks fine

 

[Captain Pants]

Only grows in clean, non-polluted environments apparently, so something to be pleased about? I rather like the look and would leave it be, but careful with that sodium hypochlorite near plastic, especially the stuff on conservatory roofs. If your walls are rendered Sodium hypochlorite is also good stuff for getting that green staining off the old paint before repainting.

 

[TheBig1]

rinse it really well after the sodium hypochloride has had 5 minutes to work. plenty of water to dilute or it will burn the cat's paws and bleach the grass

 

[chrisinplymouth]

Thanks all..... I’ll have a look in the garden centre.... though I’m tempted to just leave it, there is quite a large area of paving around the house and not sure I want to use the quantity of chemical it would take. Thanks for the quick response, I guess we’re all at a loose end!

 

[Hollyberry]

I asked at our local garden centre. Although he has a spot on local radio, he did not seem to know. I would be interested to find out, including a few white spots. Will the sodium chlor. harm our cats?

Don’t think it would be good for them. Possibly burn their paws, then they lick their paws...... I think you’d have to be able to shut them inside while you treated it, waited for it to work, then rinsed it off and it dried. Like others have said, I think it adds character.

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[Flook]

Her indoors uses Bleach, pours it on straight from bottle, a little at a time, then using a good stiff broom rubs it well in. She does about six slabs before rinsing off. She does not Karcher beforehand either, the slabs are green and well spotted, but they come up like new.

 

[davejen]

I had these marks on the drive after cleaning with S/C, never did come clean even after more applications,
save your money!
Cheers, Dave

 

[Vipar]

I have done dozens of my neighbors gardens including my own and never had a problem getting rid of the moss and the black marks.
My method is to soak everything first have a cuppa then attack them with my Karcher 256 pressure washer then fill watering can with a inhibitor. Diluted to taste. You really need to use the lance tool. And have it about 3” from the slabs/ concrete. It’s so powerful that I am afraid to use it on the van even on low jet setting. PS it will destroy any loose pointing.

 

[Cliffdale]

Thanks all..... I’ll have a look in the garden centre.... though I’m tempted to just leave it, there is quite a large area of paving around the house and not sure I want to use the quantity of chemical it would take. Thanks for the quick response, I guess we’re all at a loose end!

It works well. Its a very strong bleach, i wore eye protection, full face mask, wellingtons and long arm chemical gauntlets plus old waterproofs!

Household bleach is around 5% but sodium hypochlorite is around 15%.

Have a look at 'sodium hypochlorite patio cleaner' on youtube. It will give you an idea how to use it.

 

[Simon Meadwell]

Try wet and forget absolutely safe and works great no nasties in it

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[chrisinplymouth]

Once again thanks...?

 

[Flook]

Vipar, I use a Worx Hydroshot on the van, battery powered, high and low pressures, takes water from bucket or mains, though I now have the Snow wash dispenser for the van, especially for the roof.

However, being in lock down for a few weeks (12 in fact), only been a week so far Ughgh, so I aint going anywhere soon, all books cancelled till further notice, and all that dosh for service/MOT/Hab check/Road tax, so far has been a waste of. . .

 

[C33JAY]

As previously mentioned Hyporchlorite mine was 11% so pretty lethal so take care Great results

 

[two]

I used sodium hypochlorite, as used to 'shock' swimming pools. You'll need a barrel of the stuff and to wear clothes that don't matter. Sodium hypochlorite is strong bleach and splashes will eat through cotton leaving moth-like holes in your clothes.
I gave up eventually but used a 'blaster' nozzle on a pressure washer instead. Not as good ab you can get very wet!
Plan C is to leave them as they are and let a patina develop.

 

[StephandJohn]

This might sound barmy but white vinegar (not malt) and bicarb of soda cleans lots of things you wouldn't have thought of. Might be worth giving it a try to avoid chemicals.

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[chrisinplymouth]

?

 

[Captain Pants]

Thanks all..... I’ll have a look in the garden centre.... though I’m tempted to just leave it, there is quite a large area of paving around the house and not sure I want to use the quantity of chemical it would take. Thanks for the quick response, I guess we’re all at a loose end!

Buy it in an agricultural suppliers. Farmers use it by the bucket load and don’t expect to pay fancy garden centre or swimming pool supplier prices.

 

[G-RMPS]

Stop spitting out your used chewing gum. If you go for a chemical solution make sure you are happy to have white cats.

 

[PeteH]

We get a similar thing, which is due to Bird droppings (Bloody Pigeons and Gulls). takes forever with a Power washer. I have had some success with "Brick cleaner" acid based from Builders Merchants.

 

[M-J]

Use Spray & Leave

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