Mortar colour match for pointing.

woody7777

I need to do a bit of pointing on the house walls, but was wondering if it is possible to get the colour to match. A house down the street has done some and it stands out as a totally different patch. 

Slinky

We had a builder repoint our house and the mortar was identical because the chap who did it knows what he's doing and has the experience to know how to get the right colour. It's unlikely you'll get a match with DIY unless by complete accident.

travis-powers

Ideally you need the same sand, same mix unless bucket gauged 5&1 mixed by one person will be different to 5&1 mixed by another and according to my bricklayer the same make of cement however you have the time to do trial mixers and compare results.

woody7777

How would I know which sand to use?

travis-powers

You don’t, sand from different merchants will vary in colour depending on where it was sourced, hopefully Stuart45 will pick up on this thread and give better advice!
However mixing up trial batches would give you a good idea on results!

stuart45

You can drop a piece of the mortar in some brick acid, which will leave you with a sample of the sand.

casper_gutman

If the existing work was done a while ago then the sand used is most likely to have been local stuff, because transporting heavy, low value bulk materials long distances is expensive, environmentally damaging and unnecessary.

Even now, the cheapest sand sold in bulk at a local builder's merchants is likely not brought from all that far away, so I'd start there.

Pre-mixed or bagged 'just add water' mortar meant for DIY sheds and small repairs is much less likely to be local - it'll be manufactured centrally somewhere, using whatever sand is local to the plant where it's made.

My house was built in the 1930s using mortar blackened with ash, so it couldn't be matched just by choosing the right sand. The builders who did our extension used powdered black 'mortar tone' to try and match it.

The trouble with mortar tone was it only took a little bit and was very sensitive to the exact amount used. This led to the bricklayers ending up repointing the most prominent part at the front because they weren't satisfied with the consistency of the end result.

stuart45

Black dye can be tricky to get a consistent finish with. Adding a bit too much water to the mix affects the colour, as does overtooling the joints, or jointing up when the mortar is too wet or dry.  
The mix needs to be in the mixer for at least 5 mins to ensure an even colour.

FreeBear

There are suppliers that can do a colour matching service for lime mortars - If you are dealing with an older property, using traditional materials is more in keeping.