We (Ian Vicary) recently had a client concerned at the type of mortar used on a Grade 2 Listed property they were purchasing. After advising them to have an asssessment carried out, we received an email from the client saying they had seen on Youtube that they just needed to spray vinegar on the mortar- if it fizzed it would confirm it was lime.
However, having researched it, it appears cement will also fizz in vinegar, just not as violently. It becomes a subjective assesssment which is not accurate. Moreover, sometimes mortar can be a mixture of cement and lime…
So our question is, how do you advise clients with regards to confirming the content of mortar? Moreover, has anyone tried the vinegar test?!
I have tried the white vinegar test and it appears to work but to be only part of the answer. If there is a bit of pointing that has fallen of or is so loose that it falls of this could be cement pointing with a trace of lime mortar on the back – it would therefore fizz anyway so you also need to look at the material and try to assess. I don’t find it all that easy. This YouTube is possibly the one referred to.