Advice regarding repointing stone exterior

Sandy7

I am looking for some advice as I would like to repoint the back of my house this year. The house is victorian with a stone exterior and cement seems to have been used as mortar which has started to crumble. The stones also appear to be quite crumbly in texture.

Can anyone please provide some advice as to the mortar I need to use as lots of the advice appears to relate to brick repointing.

Any help would be gratefully received.

ormus

maybe sandstone then. pollution over the years has played havoc with soft stone.
afaik pointing is done in the usual way. when was yours last done?
maybe the mortar mix was made wrong.

Dry_Rot

You need a nice soft and porous mortar so Lime is the better choice - not cement. Soft stone needs a soft mortar, otherwise water which soaks into the wall when it rains will be trapped in the bed joints by the hard cement mortar. It then stays wet for longer and evaporates through the stone - depositing salts in the stone and eroding it. Google Womersley Associates, for a nice web site with recommended mixes and pre-mixed natural products.