does it have to be a lime based mortar?

[Anonymous]

I know very little about stone and seek your advice. Our 100+ yr old house needs repointing and chimney cracks repaired. One (very expensive) stonemason told me the 'wrong' mortar had been used previously and that it should be replaced with lime based pointing. Another has told me this is unneccessary and cement based would be fine, though he would use lime if we wanted him to. Most of what I have read talks about lime/sand. What are the basic pros and cons of each? I want to use the right thing for our house. What would you advise?

 

[Anonymous]

I'd believe the stonemason - he's spot on.

The other person I'd be very wary of using as he may not have much idea and use lime 'with a bit of cement added' or cement with a bit of dry lime - neither is what you need. You need non-hydraulic lime with sand.

 

[Anonymous]

Jane
I agree lime based mortar is the correct thing to use if you do not want to see yourself on here in 10 to 20 years from now ( if it's still running ) asking for advice on flaking stonework.
The building I live in was renovated by a moden builder in 1989. I am now having to rake out cement pointing 3 floors high as the stonework has cracked , and whole faces have come away. Save yourself hassle and expense , get it done right in the first place , and you will never need address this issue again.

 

[Anonymous]

Er, yes, without a shadow of a doubt!