Rust stains from scaffolding - Best removal method

[peteuk]

I have looked through previous posts but am unsure what I should start with:
We had to have a new roof and the scaffolding has left 17 'scaffolding feet' shaped rust marks.
The roofer has said the scaffolder says it is the 1st time it's happened. Jet wash removal was the scaffolder's advice and that didn't work.
The roofer intends to use brick acid to clean them off. Although the patio is old we do not want to replace it having met lots of unplanned upheaval and expense in our new house

The patio is mainly 450 x 450mm buff coloured paving slabs with block paving 'features and edging' and is aged (I don't know how old). The slabs look like they could have come from somewhere like a DIY shed but I don't know how to tell. Both the block paving and slabs are stained.

I have looked at some of the solutions used / recommended on this site and others. Results seem mixed or maybe better suited to iron compounds within the slabs. (The only attempts so far have been the jet wash and scrubbing bleach on 1 of the marks when 1st seen).

Please can you advise:
1). Should I stop the roofer trying brick acid?
2). If so, which of the possible solutions should I try first in my circumstances, assuming the lemon and / or cider vinegar don't work? Most popular options seem to be:
- an Oxalic acid based treatment
- Lithofin Bero (acidic?) or Lithofin Rust-ex (non-acidic?)
- Pavetuf
- Net-trol

Thank you for your help,
Peter

[dig dug dan]

I brought some rust remover from Amazon for something similar. It was expensive, but it did the trick. From memory, it smelt like riben when I applied it best with a brush. I left it for 15 minutes and it turned purple and washed off.

[peteuk]

Thanks Dan, I guess you don't remember what you used else you'd have said. But it's reassuring to know something will work.
Can anyone else recommend something? And should I let the roofer give the brick acid a go?
Cheers

[RAPressureWashing]

Please don't let the scaffolder use brick acid!! get's my back up when I see people reaching for either brick acid (hydrochloric acid) or Hypo (sodium hypochlorite ) as the be all and end all to paving problems!!! rant over.

Products that are safe to use and are the correct way to go are,
Oxalic acid can & does remove some not all rust stains, you could use something like Net-Trol from Owatrol as it's all pre-formulated and ready to use.I use 100's of litres of this over a year so can recommend it. You just need to be careful you don't bleach the surface if spot cleaning, do the whole slab etc.
I have tested the Pavetuf one (can't remember it's name)and it's very good.
Have used Rust-Ex from Lithofin and again good product
Tensid do a ferrous stain remover which is very good & again have used it. They also do rust removing poultices.

As with any of these make sure it is safe to use on your surface/stone and read all instructions

Please don't use an alkaline cleaner first (hypo/bleach etc) as this can set a rust stain and make it more difficult to remove.

[dig dug dan]

Thanks Dan, I guess you don't remember what you used else you'd have said. But it's reassuring to know something will work.
Can anyone else recommend something? And should I let the roofer give the brick acid a go?
Cheers

I found the one I used from my history.

https://www.amazon.co.uk/gp....8&psc=1

[peteuk]

Thank you Dan and Roger,
I will let you know what I use and how I get on.
Cheers,

[dig dug dan]

Pictures before and after please!

[peteuk]

Pictures? Ok, no problem.
Well having little faith in lemons or vinegar I decided on buying some Net-trol because of Roger's strong recommendation, internet reviews and pricing. But before committing I used my wife's cider vinegar on 6 of the stains.
I applied for 5 minutes each time, rubbing with a brush, not letting get dry, then rinsing off.
I was very surprised. It hasn't got rid of the marks (even after 2 goes on 2 of them) but it is much better.
So I will try on all of them and repeat. If still no good I will order the Net-trol but hopefully the cider vinegar will do the job eventually.

I guess the reason for only applying for 5 minutes is to protect the 'slab' so I will continue in this way but I may extend the timing a bit further as it didn't seem to have any bad effect.

Thanks again to both of you for your advice. I will update with before and after photos in the near future, weather permitting...
Cheers

[RAPressureWashing]

If you are going the "Vinegar" route, then just try White Vinegar, even a bottle you can get from a supermarket, it can sometimes work, shouldn't do any damage to the stone/surface as it's Acetic acid which is pretty weak in the scheme of things. It might "whiten" the stone if spot cleaning, if it does, but get's rid of your rust stains, we could address that problem later.

[peteuk]

Thanks Roger, just seen your post as I was going to post some photos.
My wife uses cider vinegar and I did request white vinegar (cheaper!) but as she does the main shopping she decided to buy more cider vinegar.....it's working to some extent so far....

It got a bit busy here so I haven't made as much progress as hoped.
I propose to show a folder of 'before' photos and a folder of 'after' photos - after only 1 treatment.
I've read the photo loading instructions but I don't have an external website. Does this alternative work?
I have loaded the files into my "One Drive".

Q. I can post a link to the relevant folders for people to click on and view them. Will this be ok?
Q. Do I need to reduce the photo size in advance or will they be ok for people as they are in the folder, not actually posted in this webpage? Mmm, thinking on, I'll reduce the size as I think they'll still need to be downloaded to be seen.

Thank you

[Tony McC]

Pete, just post the link and peoples' browsers will adjust the photies to an appropriate size

[peteuk]

Thanks Tony,

As requested please find the link below. I have put the pictures into 1 directory and renamed and numbered them so you can see the before and after effect after 1 go with the cider vinegar.
There are 7 of the 17 examples I am dealing with.
It was an overcast day so maybe that's why the paving looks pale and washed out, and the rust not so bad. The paving is old but still retains it's buff colour and the rust looked / looks worse in my opinion.
Even so it is a vast improvement and my wife will accept it if I carry on.
My aim is not to make it perfect. I am thinking to break up the defined lines so that the rust looks like a feint feature of the blocks - I am lucky that the blocks already show signs of age, that my wife considers to be character.

https://1drv.ms/u/s!Ao8_zjrfOGe3gc9VWSYEALrqF33tyw?e=LqSrEi

I'll post another link when I've made them fade further, unfortunately I've cricked my neck so it may be a few days if that persists.

Thanks again

[lutonlagerlout]

how long was the scaffold up for?
and generally scaffolders use wooden sole plates beneath their metal feet?
good luck
LLL

[Tony McC]

It's definitely made a marked improvement!

I think you've been lucky in that the rust was largely limited to the surface and had not been able to penetrate the paving to any great significance, as can happen with mosskiller and longer-term exposure, but that's not to take anything away from what you've achieved. It's a useful fix for such surface stains and I'll emphasise itspotential on the Stains page of the main website.

[Tony McC]

Would you allow me to use a few of your images to illustrate the potential for ACV on that Stains page? You would be credited as the copyright owner, naturally.