Is this lime plaster?

[curium]

Hi

I posted about the wall of my bedroom in a 1934 semi-detached house on a different forum and they suggested that it might be lime plaster so I have posted here as hopefully you guys will have a better idea. The house has solid walls - no cavity.

The previous owner had installed lining paper. Due to the lack of cavity and this being an external wall I thought I'd look into removing the plaster and installing dot-and-dab insulated plasterboard.

I removed the skirting boards which revealed what looked like a typical gypsum skim coat. I've hacked away at it and there is a very powdery substance which appears to be on top of as well as in between (the pointing) the bricks.

I'd appreciate your opinion on what I'm looking at (clearly not gypsum plaster) and how best to stabilise it so that I can either install insulated plasterboard or a gypsum plaster render.

Many thanks

 

[Devon lime specialist]

That is lime plaster if you have no cavities in your walls then putting gypsum over the top will only cause damp the wall needs to breath

 

[curium]

Thanks for your reply.

Is it normal for lime plaster to be so friable? Presumably the mortar is also lime?

What are my options for getting a smooth surface to paint on and insulating the internal surface?

Many thanks

 

[Retired Spread]