pointing mix?

It could also be that white cement was used in the mortar. If so, you just need to use white cement instead of normal portland cement (which is grey) with the sand. Cement colourant comes in a range of colours. It's always very difficult to get a perfect match as the original will have been weathered also.

JD
October 2009

The "white" cement may be lime mortar...

"By the 1950s the use of lime in building construction had virtually ceased. Although cement has undoubtedly made possible buildings which could never have been constructed with lime, cement's consistent use in the repair of old buildings has led to increasing problems, especially with damp.

Both cement and lime based methods of construction work effectively when properly maintained. But a hybrid of the two-solid walls with a soft lime mortar core and hard cement pointing, for example - is doomed to eventual failure."

i.e. if your house is old and has Lime Mortar it's not a good idea to point over with modern cement - it will look good for a while but damp will be trapped causing internal problems and freezing will make the pointing crack and fall out - five years if you're lucky.

Peccavi
October 2009