What’s the correct way to remove cement stains from Natural Stone?

What is the best way to remove cement stains from natural stone?

We are writing this blog to try and help you avoid what happened to a lady who contacted us recently.

Mrs B had unfortunately had her Kandla Grey Sandstone patio damaged by her contractors, who were woefully uninformed about the right way to install and care for natural stone.

They didn’t remove cement stains from their work area correctly, and our customer thought  her patio was ruined

In their attempt to remove spilled cement (2) they have caused rust staining (1) by using the wrong product for the job

Stained Kandla Grey-caused by use of brick acid- shows leached oxide depoists-use RPB Rust REmover to remove

Luckily, Stoneworld have been able to help her rectify the situation. We understand stone and how to care for it.  We urge all our customers to take our advice which we are more than happy to give about any aspect of stone care and maintenance.

Natural stone surfaces are versatile hardwearing and beautiful products to use, and investing in them will add ambience and value to your home.

Generally, they are very easy to care for but there are a few things that you need to think about when choosing cleaning products to use on them.

Please take note of this very important message:

NEVER USE BRICK ACID ON NATURAL STONE SURFACES. 

Why is brick acid the wrong product to use on natural stone?

It is too harsh, extremely corrosive, and on certain stones will cause chemical reactions that will result in severe rust staining to the surface, spoiling the appearance of your stone patio or floor.

The high content of hydrochloric acid in brick acid is simply too harsh and corrosive to use on stones like sandstone, limestone, granite and slate.

Not only will it destroy the surface by eating into it, it will draw iron deposits from within the stone if they are present.  Some stones are more susceptible to iron staining than others, but in this example you can see that the use of brick acid on Kandla Grey Sandstone has created a really strong reaction bringing iron to the surface and leaving a strong yellow stain on the staone.

Back to our case study:

Mrs B now needed a product to remove the rust staining that has occurred after the wrongful use of brick acid.

Plus, she still needed an effective cement remover for the remaining cement spillage on her patio.

What is the right product to use on natural stone to remove rust stains?

To remove the rust stains we recommend Rob Parkers Best Rust Remover. This product will remove the orange brown deposits that come to the surface of some stones.

Besides this unfortunate incident where brick acid has drawn rust deposits from within the stone, rust can leach out from some stones naturally.

The use of certain lawn feeds and weed killers also contain ferrous sulphates.  These can cause rust leaching from natural stone too.  We recommend swilling away any spillages of feed/weed treatments promptly to avoid staining.

Read a previous blog where we have successfully treated some old paving of ours with Rob Parkers Rust Remover>> which has brought it back to as new condition

Buy Rob Parkers Best Rust Remover now>>

What is the right product to use on natural stone to remove cement spills?

For the removal of cement spillage on natural stone Stoneworld recommend the use of

 Rob Parkers Best ConClear. 

It has been formulated using a much gentler ingredient, glycolic acid.  Whilst our product is manmade, it mimics the glycolic acid. This occurs in nature and can also be derived from cane sugar.  This substance has low corrosivity, and is biodegradable, making it gentler on your stone and is kinder to the environment.

Rob Parkers Best Conclear is highly effective and environmentally kind.  It is ideal for use on natural stone surfaces, and will also work on many other substrates,

Buy Rob Parkers Conclear now>>

We are happy to report that our advice to Mrs B has restored her Kandla Grey Sandstone Patio to its former glory.

43 thoughts on “What’s the correct way to remove cement stains from Natural Stone?

  • 18th February 2020 at 3:48 am
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    Hi we’ve had granite paving in the patio.
    To clean cement the builder used first wash , then sealer and was also using brick cleaner to clean the brick steps.
    The paving has faded. Any chances of putting it right ?
    Will there be further damage or discoloration ? Please help. Thanks

    Reply
    • 2nd March 2020 at 10:36 am
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      Hi Sonal, the liklihood is that the brick cleaner has removed the surface finish to your granite paving (obviously we cannot be sure without seeing exactly what has happened here.)

      Reply
    • 4th June 2021 at 11:09 am
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      I have a new patio and resiply the joints but it’s gone all over the stone. Tried jetwash it but it’s not budging

      Reply
  • 20th April 2020 at 10:40 pm
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    Hi , I have a natural stone gray patio and it has brush marks on the stones from when it was laid and jointing compound brushed in without the stones being wet enough . Jetwash doesn’t get rid of them, I imagine it’s almost under the surface of the stone ? What would you recommend to get rid of the brush marks ? Many thanks

    Reply
    • 28th April 2020 at 4:51 pm
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      Hi,
      Please send photos and we will advise. We think it will probably be cured with ConClear, but lets check before you buy.
      Please send a further email with photos to sales@stoneworld.co.uk

      Reply
  • 3rd May 2020 at 1:44 pm
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    Hello, I am looking to clean my sandstone paving as it has cement stains near the joints where the builder pointed between the paving slabs.

    My question is if I use Ron Parker’s Best Conclear whilst it will clean the mortar residue off the paving slabs will it not also attack the mortars joints between the paving slabs?

    Kind regards.

    Reply
    • 18th June 2020 at 12:39 pm
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      Technically it would, but if you use Conclear correctly then you would not be letting the product on the joints.

      Reply
  • 16th May 2020 at 10:08 am
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    Hi I have recently laid a sandstone patio, but there are smeared cement stains on flags even a footprint is visibly it. These smeared stains seem to have been more apparent as it has dried and seem ingrained.I feel I have ruined the look of the patio, am I being too hard on myself thinking tee is nothing I can do to get rid or lessen these unsightly stains. A friend of mine has said they should come off as the flags draw all impurities up and that I should wait for a good few few months before even sealing over my flags which was my intention.

    Reply
    • 18th June 2020 at 12:38 pm
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      ConClear is our product that we recommend for this problem, but care should be taken, depending on what stone you have laid. Please refer to http://www.robparkersbest.co.uk for more information

      Reply
  • 30th May 2020 at 5:04 pm
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    Looks like I have done all the wrong things by using brick acid on natural stone slabs, and have got a milky look now , are they completely ruined and need to come or is there a remedy to fix
    Mark

    Reply
    • 18th June 2020 at 12:36 pm
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      There are various things you could try to retrieve your slabs. We cannot advise further without a lot more information about what stone you have used. You may be able to ‘scour’ the cloudy film off, or maybe enrich the colour with Colour Enhancing Sealer. Please look at http://www.robparkersbest.co.uk for further advice.

      Reply
    • 12th July 2020 at 3:24 pm
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      Is conclean safe to use on raj Green indian stone l have had the stone flags pointed with mortar big mistake

      Reply
  • 5th June 2020 at 12:08 pm
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    I have buff paving slabs they have been covered by decking for years I have took up decking and want to clean my stones up they have marks on where the frame had been from the decking what’s the best product for this thanks in advance

    Reply
    • 18th June 2020 at 11:03 am
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      Rob Parkers Best Patio Cleaner should remove any organic staining. If there is rusting from any metal then Rob Parkers Rust Remover will halp.

      Reply
  • 17th June 2020 at 9:41 pm
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    Hi, I have just got charcoal limestone paving installed and it’s covered in cement marks and it looks light grey instead of charcoal. I have advised the workman not to use acid cleaner to remove it after reading lots of articles. Could you recommend how best to remove this without further damage.

    Reply
    • 18th June 2020 at 10:57 am
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      Hi Tracy, usually we recommend our Rob Parkers Best ConClear product for removing cement stains. However, care must be taken on dark limestone as it can discolour the surface.
      Read our blog and you will note that on black limestone it is important to use the product sparingly and diluted. Try a test area first.
      Its a tricky one, as if you have marks all over, then it sounds as if you will need to treat the whole surface.
      We also sell Rob Parkers Best Coloure Enhancing Sealer that may help after the clean up, which will enrich the colour of the stone- it does make the stone appear wet though- not everyone’s choice.

      Reply
      • 24th June 2020 at 7:53 pm
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        Ive just had India sandstone layed on patio builders left cement mark s everywhere whats the best to remove cement

        Reply
  • 19th June 2020 at 7:22 pm
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    I have smeared cement over quite a few grey Indian Sandstone slabs. Will conclear remove this and will it look as it should after?

    Reply
    • 26th August 2020 at 9:52 am
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      We recommend the use of Rob Parkers Best Conclear for the removal of cement stains on natural stone paving

      Reply
  • 28th June 2020 at 5:01 am
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    Hi I had a builder just lay slabs and he left grout haze, so he removed this with brick acid Twice and my light gray slabs are now left with orange unsightly marks. I am devastated and he says he will come back again with brick acid but I think they now look worse! Please can you help as I do not think he knows what he is doing and I spent thousands on sorting my garden. It’s actually making me ill at the prospect of this not being retrievable,

    Reply
      • 10th August 2020 at 10:07 am
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        I have used brick acid on my grey limestone to remove cement which has come off but my limestone is now cloudy and I haven’t sealed it yet. I am hoping you can recommend something to restore it original color any finish. I applied Stontex professional sealer on a test area and it’s better but still a bit cloudy. Please help.

        Reply
        • 26th August 2020 at 9:46 am
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          We never advise using brick acid on natural stone paving-it is too harsh!
          We recommend Rob Parkers Conclear for removing cement residue. I would suggest you contact sales@stoneworld.co.uk and ask for advice using a new product which may help. Rob Parkers Limestone Restoer. Not yet released but coming soon!

          Reply
  • 16th July 2020 at 9:07 pm
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    Hi we have recently had a granite patio laid, the contractor used a resin sweep in compound, but didnt remove the residue correctly, resulting in dark stains and marks throughout the patio.
    We have tried some products including resin and epoxy remover but has only had limited sucess.
    What do you recomend to to bring the slabs back to its natural condition.

    Reply
    • 29th July 2020 at 3:15 pm
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      Hi what you need is Rob Parkers best Stone Stripper. The issue you have is resin from the jointing compound has stained the paving. Used sparingly and with care this will rectify the matter for you.T

      Reply
  • 20th July 2020 at 12:22 pm
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    Hi, I have indian sandstone paving slabs and when I had flooring laid they left screed on it. Also I am getting rust staines coming through on some slabs. Can you advise me please on what is the best products to use?
    Thanks

    Reply
  • 20th July 2020 at 12:27 pm
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    Hi, i have sanstone paving slabs and whilst I was having flooring fitted they left screed on the slabs. Also I have rust patches coming through on some of the slabs also. Can you recommend for me please what products to use and how I go about using them?
    Thanks

    Reply
    • 26th August 2020 at 9:36 am
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      Please look at our sister website http://www.robparkersbest.co.uk where you can read about Rob Parkers Best Conclear for removing cement stains. Also, you will find our wonder product Rob Parkers Rust Remover which can deal with the rust patches

      Reply
  • 26th July 2020 at 8:59 am
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    Hi, I just had some light grey Indian stone paving done, the landscaper washed it down after with mortar acid. I now have may of the areas, whole slabs, going a yellow colour. Any ideas how I can stop this and rectify it ?

    Thanks

    Reply
  • 30th July 2020 at 10:50 am
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    Good morning, we have recently laid black limestone slabs, like many others we have cement stains from pointing. I have brick acid but noticed is states not on limestone. What would you recommend?

    Reply
    • 26th August 2020 at 9:34 am
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      We recommend Cement stains are best removed using Rob Parkers Best Conclear. However, extra care must be taken when using on black limestone. Follow instructions very carefully.

      Reply
  • 31st July 2020 at 11:24 pm
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    Hi There,

    I have just laid a 18 square metre sunken patio using beautiful Indian Buff Sandstone for a good friend of mine – really pleased with how it looks overall apart from a small number of cement stains on about half a dozen of the slabs … I’ve tried really hard to wipe/sponge off any mortar that came up between the slabs as I used the mallet to get them into position (used a full mortar bed for the entire patio) and disappointed that even after cleaning/scrubbing and more scrubbing using HG P31 solution that the stains haven’t really changed at all, one slab my finger prints are visible even though i wiped off the residue with a sponge as I laid each slab – so I’m really keen to know what is the best and most effective solution to clean of cement/mortar film so it looks like new or is this just something I have to live with. Its not terrible by any means but a close look at the slabs and the cement stains are quite obvious.

    Please can you help?

    Rob

    Reply
    • 26th August 2020 at 9:32 am
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      Do not use brick acid- too harsh on natural stone! We recommend Cement stains are best removed using Rob Parkers Best Conclear. However, if you have used Resin based jointing compound you will need to use Rob Parkers Stone Stripper

      Reply
  • 7th May 2021 at 4:54 pm
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    Hi. We have had a slate paving slab patio laid and the contractor has left concrete stains all over it. He used sealer and told us that this would cover them but it hasn’t. Also, paint was spilt on it and in the effort to remove it, was rubbed in leaving paint smears too. What will remove these?

    Reply
    • 11th May 2021 at 12:14 pm
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      Hi Ray, thank you very much for your enquiry. With something like this you will need to remove the sealant first before you can tackle any of the other issues that you are facing, we recommend using our Rob Parkers Best Stone Stripper (this will also remove the paint stains on the patio as well). As for the concrete stains we recommend using our Rob Parkers Best ConClear. You can find all the information about the products and how to apply them on the website: https://robparkersbest.co.uk/

      Reply
  • 10th May 2021 at 10:21 pm
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    Hi I have used rob parkers con clear on red sandstone walling to remove lime based mortar however significant rusting has occurred. Would you recommend rob parkers rust remover in this instance

    Reply
    • 12th May 2021 at 2:12 pm
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      Hi Marc,

      Thank you for using Rob Parker’s Best. We would recommend using our Rust Remover. Good luck!

      Reply
  • 1st June 2021 at 3:01 pm
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    Hi there,

    Our beige sandstone has been sealed too soon after laying and is now covered in what can only be described as watermarks. is there a way to remedy this? Or is there something that can remove the sealant from the stone to enable it to dry out fully before attempting to reseal?

    Many thanks

    Reply
    • 4th June 2021 at 11:15 am
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      Good Afternoon Amelia,
      The best product to remove stone sealant from the surface of the stone is Rob Parkers Best Stone Stripper, this will remove the layer of sealant that has already been applied and will allow the stone to fully dry before you wish to apply more sealant in the future. You can find the product and more information on how to apply it on the website: https://robparkersbest.co.uk/products/rob-parkers-best-stone-stripper/

      Reply

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