Oh no, not another conspiracy ... "Registered" with who ?
rendering over expanded metal, over rockwool is an extremely bad idea, given
that the render will crack up within months allowing water to soak the
rockwool underneath, this will then freeze in winter, and then all the
rendering will be blown off.
wet insulation doesn't insulate.
No, no, you don't use rockwool, you use celotex, EML, and a latex
modified render. A house near me had it done. You could see the boards
on the wall before the render went up. Normal builders did the job, not
registered spooks. Of course the whole thing may crack up and fail,
buts it's been through a winter, looks OK.
The stuff they use is weird, it's like plastic, that is to say, if you try
to chip a piece off with a hammer and chisel, it comes away like stringy
nylon type stuff...it's hard to describe, exept that it's like plastic -
this expands and contracts with the weather and is obviously completely
If you used rockwool you would be silly, and with such a lack of
stability, you may need some special render to survive. Rendering over
celotax is not much different to rendering over a normal wall, maybe
slightly less key I suppose.