"Andy Hide" wrote in message
om...
I have previously used a mix of 5:1 Sand/Cement to patch up blown
areas of plaster in my c1910 house. I have then gone over this with
multi-finish. Some of these patches have developed hairline cracks and
it was suggested that adding lime to the mix would help allow for any
slight movement of the house. It was built with lime mortar.

I have now changed to a 6:1:1 Sand/Cement/Lime with the sand being
Wickes (red bag) "for use in bricklaying and internal rendering". Is
this the same as plastering sand ? Would plastering sand be better in
this case ?

Having left the new mix to dry out overnight I come back this morning
to find large cracks have appeared throughout as it has dried out.
Things are so bad I think I am going to have to start again. Cracks
are worse at the edges where the wall meets the door frame (weakest
point ?).


Why not just get rid of the cement and use a 4:1 sharp sand:lime mix. This
will be flexible enough for any circumstance and you can smooth it out for
days to come if cracks appear.
Obviously a real PITA for professional work but fine for DIY.