Hi, this my first post here. My house has a cavity breeze block and stone extension built in the 60s, so I assume the original mortar would have been cement. I’ve just removed a horrible sand cement render from the stonework on the outside, not going to re render. I need to re point where it’s been pulled away with the render. Is there any point doing it with a hudraulic lime mix if the mortar the stone is bedded with is cement based? Bearing in mind its a cavity wall so damp inside is not an issue, but I do want to preserve the face of the stone if I can. Thanks
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Repointing cavity stone wall with lime
- Thread starter andrew700
- Start date
stuart45
Member
- Messages
- 735
- Location
- Somerset, England
Whenever you repoint, the rule of thumb is to use a slightly weaker mix than the original. The only real exception is for example is on a new build when the mortar was so weak the weather is taking it out too easily.
So in your case the use of a hydraulic lime would probably help.
So in your case the use of a hydraulic lime would probably help.
The other reason to repoint in lime even given the existing modern construction would be for a more traditional appearance. I personally vastly prefer the contrast of a creamy white mortar with darker stones that you get with lime. These days I dislike the iron grey of cement mortar. Maybe it just reminds me of too much pain…
stuart45
Member
- Messages
- 735
- Location
- Somerset, England
You can achieve a similar colour using white cement and coarse sand finished with the churn brush. OPC, does give that grey finish, especially when a metal tool is used to joint them up.
White cement is also much better when a dye is used to change the colour.
White cement is also much better when a dye is used to change the colour.