gypsum over lime... then what?

[ljn]

I have a listed building, 1840 circa, neoclassic revival, bought from a guy who recently rennovated it.

The conservation officer is well aware of th e "B&Q" coaving and fireplaces from the plaster shop down the road etc, and is cool about me removing them and replacing them with something more fitting.

I was wondering if anyone had advice on what to do with the interior walls. I have peeled back tiny bits of the plastic embossed wallpaper to reveal modern pink skim. And its not very well done and not flat - where it's thicker, it goes flush with the skirting boards and looks ugly.
OK, so you don't skim over orifinal lime plaster, but what do you do if someone's already done it? I'd imagen trying to remove the new plaster would cause loads of damage the the original plaster below.

Also, on some external walls, there is some kind of old lining partition - I haven't poked through it to investigaate yet, but I presume its lath and plaster. in parts, this has been removed - the skirtings wave been added to and the architrave around that side of the wall is twice as deep. The difference between the hollow lined wall and the solid sounding one is about 7 cm

I presume it must have got rotten, so the previous owner removed it. Do you think that could be the case? Did laate Georgian /early Victorian buildesrs do that? If so, what would you reccommend I do once Iv'e stripped the wallpaper off? Reinstate the "original wall insulation"? leave as is? or remove the insulated parts, as this must be say a 1950's adittion?

 

[Anne]

I'll leave the exterior to others as I'm not clear what you mean exactly but as far as the interior goes I don't think you have to live with someone elses ugly modern plaster just because there may be old plaster behind. Have you tried getting a chisel between the modern and older coats? Modern plaster is usually not that hard to get off and certainly easier then concrete. It also doesn't sound like you know how old the old stuff is yet until you do just go with care. We can't save all old plaster eventually it gives up and won't stick if it's seen hard conditions. I'd have a good careful poke and see exactly what you've got.

 

[MDE]

I removed some gypsum from lime plaster quite easily by hitting it - the gypsum cracked and flaked off while the lime stayed intact. I'd try a patch that isn't too obvious first, though...

 

[MdB]

I removed some gypsum from lime plaster quite easily by hitting it - the gypsum cracked and flaked off while the lime stayed intact. I'd try a patch that isn't too obvious first, though...

Worked for me too though there was only a lump or two of lime under the many layers of render / plaster on top. After a bit of practise I was able to take each layer off one by one. It does help if you have damp problems though, I had to go a lot more carefully on the dry stuff.