Lime plaster - yes or no

[Astacus]

Here is one for the Victorian house experts.
My daughter has bought a 2up 2down Victorian terraced house. It has a bedroom and a bathroom upstairs and that’s it. The house was built in 1860 and has lime mortar. We are gutting it back to the bricks and refurbing completely as it was in such a state. It’s a great Dad and daughter project.
Upstairs is the next stage. The original lime plaster has been over skimmed with modern but that is all coming off down to the bricks as the plaster underneath is in a very poor state.
The question is do I get the walls lime plastered or cement plastered?
The house has been recently repointed with modern mortar and the downstairs was well done but in modern plaster.

I think my thinking is half the house has been done with modern materials, which maybe shouldn’t have been used. Will it make a difference if I do the upstairs properly given the pointing is modern too, so the majority of the house ‘breathing’ has already been compromised.

Or am I just over thinking this?

Any advice very much appreciated.

[bigpriest]

If the ventilation is good (in an older property that sometimes means having to accept internal draughts), there is little movement and there are no signs of leaky gutters or downpipes, I'd say it won't make much difference.

[DKL]

Does it have a cavity? If not then I would want as little modern material as I could get away with. Concrete pointing and gypsum plaster is almost certainly going to cause issues. But you have it downstairs already so upstairs would be less critical. Personally I'd be using lime and breathable paint as you have the opportunity to. Downstairs is just a watch and wait, no issues then sit tight, if it gets damp then sadly something would have to change. I'd start with the pointing as it's less disruptive.
I've found just stripping off layers of emulsioned wallpaper makes a surprising amount of difference so every bit helps.