How do I know if my walls are lime plaster?

[Anonymous]

How do I know if the walls of my house have lime plaster? I have had two rooms skim plastered but now, reading this site, realise I may have made a mistake. A few very fine cracks are appearing. The house was built about 1900 near Stoke on Trent. The walls seem very hard - but assume this is not any indication. Is lime plaster really necessary on a late Victorian house?
Whilst writing - the walls of the room I am currently stripping of paper have (underneath the paper and first coat on the wall) a dark red paint like substance which can be stripped of with steaming, but leaves a red stain. What is this? Can you skim over it once it is stripped off?

 

[Anonymous]

Lime plaster was used until at the least the 1930s, possibly longer. Unless the house has been replastered it is inconceivable that a 1900 house would be plastered in anything but lime.

Walls in 1900 would either be papered or distempered. The coloured layer you talk about could be distemper. Traditional distemper is made of whiting (powdered chalk) and pigment, bound with a natural glue (made of animal skin/bone or caesin, a milk based glue)