Crumbly wall

[Micky]

Just wondering how best to deal with latest bit of our house that is crumbling...ex estate workers cottage (hence lots of cheap bodging by estate for many years (really bad cement pointing spalling bricks), followed by whistle stop cheap refurb by housing assoc in order to rent out, lots of bad glosswork and ignoring of rotting window frames!) cottage 1860ish, on sandstone plinth, recent work on stair kite winder (woodworm) revealed earth floor under the stairs am wondering if this is contributing to the fact that some of the lining paper has detached by bottom stair and revealed crumbling plaster (which I take to be lime) how best to repair.....before discovering this excellent forum shamefully I patched up crumbling mortar above window lintels with Knauf Patchwall...I realise now this was not very sympathetic! Without peeling back more lining which is still firmly attached (dont want to go there) the problem patch is only small 10" by 10" roughly.
Whats to be done?
Micky

 

[MdB]

Whats to be done?

Post a pic. This will enable the experts to comment better. Doesn't sound like it would be difficult to replaster in lime though.

 

[Schoolmarm]

And don't worry about the earth floor. Is it dry or dampish? I have just removed a lump of opc mortar that was replacing a broken quarter of stone flag. The soil underneath was bone dry but it is fairly central to my house. Are your stairs next to an outside wall?

 

[Micky]

Thanks Schoolmarm can you believe we don't yet posess a digital camera...there are plans afoot to purchase one and join the 21st Century however ...yes although the wall that is crumbly is at a right angle to the outside wall if that makes sense...I was not present when earth floor was exposed but I'm told it was fairly dry - sorry I realise a photo would definitely help here.