My ceiling spec includes 25mm celotex under the ceiling joists to
minimize cold bridging, and then plasterboard. I can't to a warm roof
for various reasons. Is it cheaper to get the celotex (secondsandco
etc) and PB, or get insulated PB ?
I've never used celotex / PB sandwich onto joists before - seems to me
the celotex would squish slightly and fail to give the PB and solid
enough fixing to avoid the skim cracking in the future.
Is this something I should consider ?
Thanks,
Simon.

In article
,
sm_jamieson wrote:
My ceiling spec includes 25mm celotex under the ceiling joists to
minimize cold bridging, and then plasterboard. I can't to a warm roof
for various reasons. Is it cheaper to get the celotex (secondsandco
etc) and PB, or get insulated PB ?
I've never used celotex / PB sandwich onto joists before - seems to me
the celotex would squish slightly and fail to give the PB and solid
enough fixing to avoid the skim cracking in the future.
Is this something I should consider ?

That's what I have here and it seems to be fine. There are some cracks
between plasterboard sheets - but no different from anywhere else here.
Flexible caulk fills them ok.

--
*Why do we say something is out of whack? What is a whack? *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
sm_jamieson writes:
My ceiling spec includes 25mm celotex under the ceiling joists to
minimize cold bridging, and then plasterboard. I can't to a warm roof
for various reasons. Is it cheaper to get the celotex (secondsandco
etc) and PB, or get insulated PB ?
I've never used celotex / PB sandwich onto joists before - seems to me
the celotex would squish slightly and fail to give the PB and solid
enough fixing to avoid the skim cracking in the future.

No it won't squish.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

sm_jamieson wrote:
My ceiling spec includes 25mm celotex under the ceiling joists to
minimize cold bridging, and then plasterboard. I can't to a warm roof
for various reasons. Is it cheaper to get the celotex (secondsandco
etc) and PB, or get insulated PB ?

Probably cheaper separately...

I've never used celotex / PB sandwich onto joists before - seems to me
the celotex would squish slightly and fail to give the PB and solid
enough fixing to avoid the skim cracking in the future.
Is this something I should consider ?

No, its quite tough in fact - it may compress very slightly under the
tension of the screws - but it won't move any further afterwards.

--
Cheers,

John.

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