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How to clean cement and lime stains off soft red bricks

Discussion in 'Building' started by chriseastlondon, 5 Jun 2021.

  1. chriseastlondon

    chriseastlondon

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    Hi. I've recently had my house repointed. It's been a bit of a saga - they pointed it with cement mortar first so I got them to rake it out and do it again with lime mortar.

    It's done now. But there are quite a few stains on the faces of the bricks - both from the cement mortar and the lime mortar. Is there anything I can use to clean them off? Brick acid? They're old (Victorian) soft red bricks so I don't want to do anything that might damage them.

    Thanks!
     
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  3. opps

    opps

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    A mate of mine is a brick pointer. When he works with lime he washes down the red rubber bricks with brick acid. Stubborn areas, he mixes brick motar tone with PVA and touches in the smeared area.
     
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  4. chriseastlondon

    chriseastlondon

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    Thanks. The lime stains aren't too bad. It's more the cement mortar I need to remove. I'll have a go at it with acid.
     
  5. ^woody^

    ^woody^

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    You need to be very careful not to get any acid into the lime joints as it will affect the lime more than it would cement.
     
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  6. stuart45

    stuart45

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    How did they manage to get it all over the facework?
     
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  8. opps

    opps

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    Having watched the guys I have seen working, when doing a weather struck finish, you allow the lower part to extend on to the lower brick. Wait a while and then strike a straight line an hour later(?). When working with cement mortar they seem to use a paint brush to remove the residue. I get the impression that lime mortar is stickier and the excess needs to be removed chemically- especially when working with red rubber bricks.

    To be honest, I know little about the subject. It just happens to be the case that I have worked at about 10 properties where Aspen Pointing have repointed the houses. Most of their work is in Ealing, London. Most the houses have red rubber bricks which are very porous. From memory they only used lime on one of those jobs, and they charged much more for the post pointing "clean up".
     
  9. chriseastlondon

    chriseastlondon

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    It's not too bad. There are mortar stains (mainly cement mortar) here and there. I'm just keen to get them off before I get the scaffolding taken down.
     
  10. stuart45

    stuart45

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    Anyone who has done a brickwork apprenticeship should be able to do a weather struck and cut repoint without making a mess of the facework.
     
  11. stuart45

    stuart45

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    If you are using acid make sure you soak the brickwork down first so it isn't soaked into the bricks and joints and works mainly on the surface.
     
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  12. chriseastlondon

    chriseastlondon

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    Thanks. I'll be careful about that.
     
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