Is this plaster or brick?

[Jblakes]

Can anybody advise if the close ups are brick/gypsum/cement or other. Im knocking behind the cooker on a 20year old extension to lime plaster. I can't workout what this is and if i should be knocking it off.

Kind regards
JB

 

[Cubist]

That's aerated concrete block. Wear a mask. They sometimes used glass fibre and sometimes asbestos to keep those things lightweight.

 

[a twig]

Yep agree - the last photo shows the face of the aerated concrete block on the right, as they aren’t the most robust the face is potentially being pulled off when you are removing the plaster hence you’re seeing the “moonscape” you are currently presented with.

 

[a twig]

They are usually used for the internal side of a cavity wall

 

[Jblakes]

So don't knock it off then, will lime plaster actually work on top of it to release moisture?

 

[a twig]

If it’s a cavity wall in concrete block then the plaster choice is pretty irrelevant

 

[Jblakes]

Bugger

 

[jamest]

I'm not sure I'm in complete agreement with a twig when he says that the plaster choice here is largely irrelevant. It won't matter much as far as moisture transfer through the wall is concerned, but lime plaster is preferable to gypsum or cement for two reasons: (1) it absorbs and releases moisture in the air and provides a nicer living environment, you read about this in various places, but I can attest from personal experience that it's improves things in that way. (2) It's carbon neutral.