Darkened cement/mortar colour

Discussion in 'Builders' Talk' started by Possom, Aug 1, 2020.

  1. Possom

    Possom Member

    It can be observed in the attachment the darkened colour of this 1930s brick mortar.

    The bottom left of the picture shows a more modern piece of cement which has been placed there at some point and is a more "standard" colour.

    If I wanted to make up some cement which was more in keeping with the original, are there dyes which can be added to colour to make it a more darkened colour?

    There's also more of a grit in it than modern sand/cement mixes.

    brick.jpg
     
  2. Jord86

    Jord86 Screwfix Select

    Look up Sika black mortar colour additive.
     
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  3. Abrickie

    Abrickie Super Member

    Your original mortar is an ash lime mortar hence the colour and texture. The newer cement mortar actually looks as if it was dyed black to blend in, unfortunately the modern mortar dyes don’t weather anywhere near as well as a traditional lime mortar. The dyes are available in either a liquid or powder form and personally for small quantities I think the powder is easier to gauge, use either a OPC cement or snowcrete and don’t exceed the manufacturers maximum ratio ( it does end well) or a quick google should find you a local lime mortar supplier who can match texture and pigment :)
     
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  4. Possom

    Possom Member

    Thanks very much Abrickie. That's very helpful info. I didin't think the original was dyed, though I'd no idea how to replicate. I hadn't heard of ash lime but that's certainly what it is. It certainly has the colour of ash.
     
  5. Abrickie

    Abrickie Super Member

    Modern dyes will replicate the colour, but you’ll be lucky to keep it for that dark for long, using sharp sand with building sand will give you the texture, or there’s the dying art of lime mortar ;)
     
  6. stuart44

    stuart44 Active Member

    Well known for rotting your wall ties.
     

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