Is lime plaster advisable on internal walls separating rooms or only need on external and party

Hi, If the walls are not a brick then yes. if they're Lathed then we'd advise to remove, then plasterboard and for the same upstairs. Always look after the bricks, they're what need to breath the most. You may still find that the walls will remain damp in some way or another for a period of time, just because either side of you may still have a cementitious material on their side.

On older properties, damp course were usually slate or tar based. If you have damp issues from rising damp on party walls I would advise an inflected damp course. I use Dryzone which can be used in either a cream application or damp proofing rods that react with damp and form into a waterproof resin, Followed by hacking off affected areas then applying hi limerenovation plaster undercoat and finish. I haven't had any problems using this system. As for stud. Lath and plaster and upper floor studwork, Remove old plaster and lath. Reboard with 12mm plasterboard and multi finish ready for decor. External walls may require a scratchcoat and topcoat using rendaguard gold addative and finish plaster for decor. Hope you find this usefull

It depends on you want the walls to breath if so it's got to done in line work and if it's listed building if so it's got to be done in line work