In article ,
The Natural Philosopher writes:
Andrew Gabriel wrote:
In article ,
Fred writes:
Hi,

I've been retrofitting celotex to a room. It's gone well except for
one slight problem: the window reveal (I put 25mm celotex inside the
reveal). I'm worried that even if I use 9.5mm, rather than 12.5mm,
plasterboard on top of the celotex that it might overlap too much of
the side of the window frame. I'm not sure how much of a problem this
will be: any overlap will only be cosmetic, it's not going to block
the window or prevent it opening or anything that drastic but will it
look "odd"?

What would you do? Use 9.5mm PB? If there is an overlap (i) it will
probably be hidden by blinds/curtains/whatever SWMBO puts there or
(ii) if we do see it, we may grow used to it.

Alternatively is there something thinner than 9.5mm PB? I don't expect
there is a plasterboard any thinner because it would be too fragile to
transport but can you plaster on top of say hardboard? Does it need
any treatment first (primer? undercoat?) or just PVA?

Or can you PVA celotex and plaster directly on to that?

Yes.

You might want a scratch coat (use bonding coat plaster)
as finish coat by itself might be a bit fragile on celotex.

You can plaster a sheet of glass if you PVA it first.

you could use rendering mesh and bonding plaster for a really thin finish.

It's called metal lath.
You would want stainless steel, not galvanised, near a window,
and stainless steel fixings. It's a complete ******* to handle.
Comes in 8'x3' sheets, and every edge is like a giant razor blade,
and even the surface is like a giant cheese grater. I used some a
few months ago, and in spite of being careful, I still managed
to cut myself several times. You don't even know you've done it,
as mostly it's completely painless at the time. Then you notice
things are getting blood on them, and you've got blood on your
hands, and you start trying to work out where it's coming from.
It's probably a bit thick for what you want, and it doesn't
necessarily lay very flat against the surface, so I'm not sure
you'd achieve significantly less than 9mm with it.

Another option I have used for a thin layer is fine welded mesh.
That came from Wickes, but is galvanised rather than S/S. I don't
recall if they or anyone else does a S/S version. It is much
easier to handle.

--
Andrew Gabriel
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