Mortar to use when replacing windows in stone house

[nigel57]

Hi,

I'm about to replace a number of windows in an old grade two listed house and would appreciate some advice on the appropriate mortar to use. The existing windows are pointed in with cement mortar but the main pointing on the walls is lime mortar.

To keep with the spirit of the listing I'm guessing that I should use lime mortar but would appreciate guidance on the type of lime mortar please.

Also, any handy tips appreciated.

Thanks,

Nigel.

 

[MatthewC]

If you use cement mortar you will find that in due course it will separate from the lime mortar underneath, with nice gaps appearing where you don't want them. NHL 3.5 is probably what you need, mixed 3 sand:1 NHL