I live in a 1950's house. It is in a small village near Bath, and so was built in cast-stone blocks which resemble surrounding houses (which are Bath stone). The mortar used is very light - almost white - and powders easily if rubbed, which leads me to think that it may be lime mortar. Is this likely? I thought that lime mortar was only really encountered on pre-1930's houses, and not on more recent buildings? At some point, another owner has added a porch, and the mortar on that is still very light, but with a distinct grey tinge, and is very hard to the touch (it doesn't powder when rubbed), so this would appear to be cement based.
My main question is this. There are various places around the house where I need to repair the pointing, and fix some ugly holes that the previous owner filled with grey mortar. I am also replacing my doors and windows, and need some mortar for bedding down the doors, and making good in a few places. Should I try to obtain suitable lime mortar for this work, or could I use cement mortar? Obviously if I used cement mortar I would have to use suitably coloured sand, and white cement - would this be a close enough match?
I haven't been able to find any local suppliers of lime mortar (although living near Bath this seems odd). Getting small quantities of lime mortar mail order I end up paying twice as much for postage as I do for the materials!