Need some advice on pointing walls

[Jasy19]

Hello,

I need a bit of advice on repointing some exterior walls. (Attached pictures)
We've had a lot of problems with the adjacent sandstone blocks getting damp and saturated with water,
giving us problems inside and on the exterior render and paint being damaged from lots of moisture in the walls.

I think I need to start with repointing these sections shown, some which seem to have deep recesses.
My question is - what mixture should be used with these stone blocks, a lime render, or a cement render?

Thanks in advance

 

[^woody^]

What's there now, lime or cement?

You need to be careful with too strong fever mixes as this will cause the stone edges to fracture.

4 or 5 and 1 if cement, and the trick is to tool the joint well to give it it's weathering strength.