Hi my landscaping contractor tells me that my request for dark grey mortar is not possible; I am told that no-one could possibly guarantee the mortar would be dark grey and also that "everyone" uses white.
I asked for dark grey based on a recommendation/review of laying indian sandstone using dark grey mortar (&subsequently seeing it in brochures); can anyone help to clarify if I am in fact asking the impossible? If not can you specify what products to use to help me out here?
Cheers, Janice A.
Janice
Dark grey mortar - Dark grey mortar - is it achievable
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confuzatron
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Ted
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You can buy powdered colours (iron oxides) to add to your mortar from any decent builder's merchants.
For dark grey I would add black powder.
I generally add black to any mortar or concrete I make unless the concrete is not going to be visible where it is placed or unless I want a different colour.
The black colouring makes the concrete look better IMO.
Make sure you read the instructions... if you add too much you will end up with black mortar and adding too much will weaken the mortar.
So your man is certainly wrong as a dark grey can be achieved.
The type of cement and sand you use will play a part in the final colour. White cement will produce a lighter grey but there also differences in colour between grey cements. Mastercrete for instance is quite a light grey but Lafarge's OPC is darker.
You could consider using a black fine to achieve a dark coloured mortar. Places such as Derbyshire Aggregates and Long Rake Spar sell a blackish fine. In fact this might be a better approach than using the coloured powders. Collux Black or Collux Grey might work well. If you try this approach I would use a grey cement.
http://www.derbyshireaggregates.com/dried-aggregates.html
Whatever your approach, it is best to do some test batches and record the mix until you are happy with the final cured colour, then stick to it and make sure each mix is gauged accurately.
For dark grey I would add black powder.
I generally add black to any mortar or concrete I make unless the concrete is not going to be visible where it is placed or unless I want a different colour.
The black colouring makes the concrete look better IMO.
Make sure you read the instructions... if you add too much you will end up with black mortar and adding too much will weaken the mortar.
So your man is certainly wrong as a dark grey can be achieved.
The type of cement and sand you use will play a part in the final colour. White cement will produce a lighter grey but there also differences in colour between grey cements. Mastercrete for instance is quite a light grey but Lafarge's OPC is darker.
You could consider using a black fine to achieve a dark coloured mortar. Places such as Derbyshire Aggregates and Long Rake Spar sell a blackish fine. In fact this might be a better approach than using the coloured powders. Collux Black or Collux Grey might work well. If you try this approach I would use a grey cement.
http://www.derbyshireaggregates.com/dried-aggregates.html
Whatever your approach, it is best to do some test batches and record the mix until you are happy with the final cured colour, then stick to it and make sure each mix is gauged accurately.
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lutonlagerlout
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Tony McC
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For dark grey traditional (hydraulically bound) mortar (as opposed to LLL's excellent suggestion to use a polymeric) you can either:
a) use silver or very, very light coloured sand as the base and add a cement dye at the rate of approx 1kg per bag of cement
b) buy a pre-batched and consistently coloured black lime mortar from a mortar supplier
c) track down black foundry sand (Garside are probably the most likely suppliers|) and use that as abase with cement dye at approx 400g per bag of cement
Your man telling you that black/grey mortar isn't possible etc. is total bollickles, and you should make him eat his aforementioned bodily parts as a partial apology for being a lying bar steward.
a) use silver or very, very light coloured sand as the base and add a cement dye at the rate of approx 1kg per bag of cement
b) buy a pre-batched and consistently coloured black lime mortar from a mortar supplier
c) track down black foundry sand (Garside are probably the most likely suppliers|) and use that as abase with cement dye at approx 400g per bag of cement
Your man telling you that black/grey mortar isn't possible etc. is total bollickles, and you should make him eat his aforementioned bodily parts as a partial apology for being a lying bar steward.
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