Remove lime plaster, how far do I have to go?

[Bruxy1967]

Hi I am the proud owner of a mid stone terrace built c1850 which has been empty for 3 years. We have damp issues at the bottom of the walls and also flagstone floors had been covered with mdf boards and carpet so that hasn't helped.
All the walls in the lounge had artex on them which we wanted to remove but when we did the lime plaster underneath has just crumbled away in many places. We will keep some of the walls as stone but the majority of the room needs to be replanted or can we use plasterboard?
We have knocked all the very loose mortar off but we still have a lot of plaster remaining which is very sandy and you can rub the sand off.
Do we need to remove all of this back to stone?
Also what are the small pieces of wood shown in the photo?
I will also post photos of the Minton tiles and flagstone floors we found. Thanks for your help.

 

[elizabeth]

Hi there and welcome. Lucky you finding flagstones and Minton tiles, now you have uncovered them the damp will start to improve. I fear If you plasterboard particularly an external down stairs stone and lime wall, it may reduce the breathe ability leading to problems with salts and damp.
You could brush off as much loose big material as possible till you are back to something more solid of the lime mortar and try a stabiliser which I believe you can brush on which I think you can find through Mike Wye or Ty-Mawr. I’m sure someone would know the product I mean. Maybe look at using cork or wood fibre boards or have a go at using lime. Also read up on Okendon and Twig who have taken walls back to stone.
There are plenty of experienced members on here who can be better help to you. Have a look through the historic posts too, hopefully you will find others who have had the same issues.
Keep us posted and all the best.

 

[Zebra]

The bits of wood are for fixing things to, they get set in the wall and then something is screwed to them. You can take them out if you don't want them.
I don't think that plaster is much worth saving. I think I would be inclined to take the view that the plaster has lived its useful life and remove it all the way back to stone, check to see if any repointing is needed, then redo with a new, coarse base coat (something like Old House Stores "coarse stuff" or mix your own), then top coat if you want, or be lazy and sponge the float coat for a rougher finish. I went on a one day lime plastering course and did my own, saving heaps of money.