Plastering Stone ?

[Skiny]

I'm due to have part of my house plastered and was wondering if there would likely be any issues with plastering onto the old stone walls?

It was originally plastered, I guess with something lime based, as it's from 1870s, however I hacked it all off as it was in bad condition in many areas. Nice parts of stone I'm keeping exposed, but things such as the chimney breast I want to plaster.

I don't like dot/dabbing boards and much prefer a solid wall. My plasterer mentioned to me when I saw him last, that he was concerned about plastering straight onto the stone and was worried it might blow.

I was wondering what people here thought?

I'll add some photos to show the state of the walls.

Also, I have an internal thermalite wall to plaster too. Is it ok to plaster thermalite if it's sealed/soaked first?

Thanks

 

[roy c]

He cant be a very good plasterer if he doesn't know how to "scut " it all !!!

 

[Skiny]

What do you mean by "scut"?

 

[roy c]

Ask your plasterer..

 

[Skiny]

I've never heard of this term before

Is there anything else that should be done prior to plastering? Anything to prepare the wall to give better results?

Thanks

 

[roy c]

If you have different areas of suction then you have to equalise it so you can spread it! Rake all the loose stuff of and wire brush it all. Then you can "scut " it. Which is basically a splatterdash mix that you throw (scut) on to the walls. It has to be quite runny so it "splats" on your wall. The mix I would use for this would be a 4-1 mix (with unibond or bonding agent ) mixed in. Then you have a wall with equal suction to work on. For the rest of the rendering and dubbing out use a 5 or 6-1-1 (lsand cement and lime) mix,, Scut is a word that be called different names in different parts of the UK and Ireland,, Good Luck..

 

[roughcaster]

Spot on Roy as usual. It's all about preparation. A good key, and a good even suction overall.