Hi All

Some advice would be appreciated on the following. I recently
plasterboarded my extension ceiling with the foil back plasterboard
under the reccomendation of the buildings inspector. The problem is
that on completion of the task and admiring my handywork I realised I
hadn't insulated! 'Doh' was said several times.

What do you think my options are, obviously I want to avoid pilling it
all down.

It is a ground floor extension, flat felt roof, all walls are to be
injection insulated and the wooden floor has celotex type stuff
underneath.

Thanks.

zoolanda wrote:
Some advice would be appreciated on the following. I recently
plasterboarded my extension ceiling with the foil back plasterboard
under the reccomendation of the buildings inspector. The problem is
that on completion of the task and admiring my handywork I realised I
hadn't insulated! 'Doh' was said several times.

What do you think my options are, obviously I want to avoid pilling it
all down.

In this situation, I think that you'll have to pull it down
to insulate properly. Sorry! Why did the Buildings Busybody
recommend foil backed PB?

wrote:
Hi All

Some advice would be appreciated on the following. I recently
plasterboarded my extension ceiling with the foil back plasterboard
under the reccomendation of the buildings inspector. The problem is
that on completion of the task and admiring my handywork I realised I
hadn't insulated! 'Doh' was said several times.

What do you think my options are, obviously I want to avoid pilling it
all down.

It is a ground floor extension, flat felt roof, all walls are to be
injection insulated and the wooden floor has celotex type stuff
underneath.

Thanks.

You say you are insulating the wall with injection.
Will the BCO let you use that for the ceiling ?
Otherwise, you'll just have to take down some of the ceiling or roof to
get the celotex in.
You didn't say its been skimmed yet. At least that's something !
Simon.

Youre right, it hasn't been skimmed yet What about if I take down
the boards at one end and shove rockwool up there and push it down with
some rods....? Would this cause any problems?

I guess the one other option I have is to leave it, but does anyone
think this would make the room too cold and would the inspector notice?
I know this is a cop out and at the end of my options...

wrote:
Youre right, it hasn't been skimmed yet What about if I take down
the boards at one end and shove rockwool up there and push it down with
some rods....? Would this cause any problems?

I guess the one other option I have is to leave it, but does anyone
think this would make the room too cold and would the inspector notice?
I know this is a cop out and at the end of my options...

Surely the inspector will not sign off the work if the insulation
cannot be proved.
Our building services were very fussy about the insulation in my
soon-to-be-started extension plans.
Note, celotex has a much higher thermal resistance than rockwool.
Also, without insulation, you will freeze and/or be skint in the winter
!
Simon.

On 13 Apr 2006 07:18:48 -0700, a particular chimpanzee named
randomly hit the keyboard and produced:

Youre right, it hasn't been skimmed yet What about if I take down
the boards at one end and shove rockwool up there and push it down with
some rods....? Would this cause any problems?

Yes. You need ventilation above the insulation. Filling with
Rockwool will block this, and, unless your joists are over 200mm
thick, the Rockwool won't be thick enough.

I guess the one other option I have is to leave it, but does anyone
think this would make the room too cold

Yes.

and would the inspector notice?

Unless he can see into the void (ie, through a ceiling rose or
downlighter), then no. He might ask you if you've insulated and what
with. It would be then up to your conscience whether you're willing
to lie.

If you haven't skimmed it yet, your best option is to bite the bullet
and unscrew the boards (unless you nailed the boards!).
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

On Thu, 13 Apr 2006 15:10:55 +0100, a particular chimpanzee named
Chris Bacon randomly hit the keyboard and
produced:

Why did the Buildings Busybody
recommend foil backed PB?

To prevent the passage of moisture through the plasterboard.
Foil-backing acts as a vapour barrier.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

Hugo Nebula wrote:
Chris Bacon randomly hit the keyboard and produced:
Why did the Buildings Busybody
recommend foil backed PB?

To prevent the passage of moisture through the plasterboard.
Foil-backing acts as a vapour barrier.

But where's the need in this application?

In any case I've never heard of "normal" moisture passing
through plasterboard being a problem.

Everyone - thanks for the respones. The boards are on their way down
as we speak, I did nail them so 'double doh'. !!

One more thing you can help me on. I know Celotex is pricey and in any
case the drawings specify 1200mm thick celotex, and I can't find any
reference to that. Is it a typo? As the roof is made of 8x4 joists so
fitting 1200mm slabs would leave very little ventelation space.

I have a local B&Q, Jewsons, Builders Centre and Wickes. Can anyone
recommend a suitable insulation slab brand from any of these that won't
break the bank? (I have already been to B&G and they don't have
Kingspan)

Best
S.G

Me again - what about a warm roof type thing? Would this be of
comparable cost and of comparable efficiency? The boards are still up
(i know I said they were coming down but I am pausing for the night).
Advice welcomed.

wrote:
Everyone - thanks for the respones. The boards are on their way down
as we speak, I did nail them so 'double doh'. !!

One more thing you can help me on. I know Celotex is pricey and in any
case the drawings specify 1200mm thick celotex, and I can't find any
reference to that. Is it a typo? As the roof is made of 8x4 joists so
fitting 1200mm slabs would leave very little ventelation space.

I have a local B&Q, Jewsons, Builders Centre and Wickes. Can anyone
recommend a suitable insulation slab brand from any of these that won't
break the bank? (I have already been to B&G and they don't have
Kingspan)

For Celotex/Kingspan I can highly recommend
http://www.secondsandco.co.uk/ - they sell 'seconds' which in my
experience have been practically as good as 'firsts' - and very cheap
too.

I don't know where you're based but they're in Powys - however I
believe they may also do nationwide delivery from the back of a lorry.

Mathew

wrote:
Everyone - thanks for the respones. The boards are on their way down
as we speak, I did nail them so 'double doh'. !!

One more thing you can help me on. I know Celotex is pricey and in any
case the drawings specify 1200mm thick celotex, and I can't find any
reference to that. Is it a typo? As the roof is made of 8x4 joists so
fitting 1200mm slabs would leave very little ventelation space.

I have a local B&Q, Jewsons, Builders Centre and Wickes. Can anyone
recommend a suitable insulation slab brand from any of these that won't
break the bank? (I have already been to B&G and they don't have
Kingspan)

For Celotex/Kingspan I can highly recommend
http://www.secondsandco.co.uk/ - they sell 'seconds' which in my
experience have been practically as good as 'firsts' - and very cheap
too.

I don't know where you're based but they're in Powys - however I
believe they may also do nationwide delivery from the back of a lorry.

Mathew

zoolanda wrote:
One more thing you can help me on. I know Celotex is pricey and in any
case the drawings specify 1200mm thick celotex

'Kinell.


and I can't find any
reference to that. Is it a typo? As the roof is made of 8x4 joists so
fitting 1200mm slabs would leave very little ventelation space.

8x4?? You sho'?


I have a local B&Q, Jewsons, Builders Centre and Wickes. Can anyone
recommend a suitable insulation slab brand from any of these that won't
break the bank? (I have already been to B&G and they don't have
Kingspan)


Are you a bit pie-eyed, S.G.? I are slightly. If you've got all that
room, then Jablite is cheap and will do the job well enough.

wrote:

"the drawings specify 1200mm thick celotex,"....I'm an arse, it was
120mm not 1200mm Celotex.............. so alternative's welcomed.

1.2m would indeed would be a rather well insulated if small room!

Polyisocyanurate Foam or PIR or Eurothane Foam are all names for the
same sort of board. Typically it is foil covered on both sides and has a
very high insulation value for a small thickness. Other well known
brands of similar stuff include Kingspan and Ecotherm.

Look for a local supplier of seconds if at all possible. Failing that
try one of the online suppliers like :

http://www.secondsandco.co.uk/

Note prices charged by builders merchants for this stuff is silly (one
quoted me nearly 30 quid for a 50mm thick sheet), got it from a local
supplier for less than half that in the end.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thu, 13 Apr 2006 18:39:48 +0100, a particular chimpanzee named
Chris Bacon randomly hit the keyboard and
produced:

Hugo Nebula wrote:

To prevent the passage of moisture through the plasterboard.
Foil-backing acts as a vapour barrier.

But where's the need in this application?

BS 5250, S8.4.3.2.2, "A cold deck roof is shown in Figure 22. This
type of roof should be avoided because interstitial condensation is
likely and its effect on the structure and insulation can be severe...
The vapour control layer should have a resistance of at least
250MN·s/g, and should have sealed laps to preserve the integrity over
the whole roof. Gaps in the ceiling should be minimized and service
openings should be avoided; if they cannot be avoided it is essential
that they are sealed".

A foil-backed plasterboard is the very least that is needed, and
strictly speaking is not nearly enough.

In any case I've never heard of "normal" moisture passing
through plasterboard being a problem.

Then you've never lived. Or at least never lived outside of Arizona,
or had anything to do with buildings.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

Hugo Nebula wrote:
Chris Bacon randomly hit the keyboard an produced:
Hugo Nebula wrote:

To prevent the passage of moisture through the plasterboard.
Foil-backing acts as a vapour barrier.

But where's the need in this application?

BS 5250, S8.4.3.2.2,
[snip]
A foil-backed plasterboard is the very least that is needed, and
strictly speaking is not nearly enough.

So if "strictly speaking" it "is not nearly enough" (your words)
then why is duplex plasterboard allowed, and why aren't the
insidious effects of *not* having a vapour barrier, or only
foil-backed plasterboard, which *you* say is "not nearly enough"
not seen extremely frequently? Answer: it is a non-problem.


In any case I've never heard of "normal" moisture passing
through plasterboard being a problem.

Then you've never lived. Or at least never lived outside of Arizona,
or had anything to do with buildings.

That is a particularly ignorant statement. I have never seen
or heard of heard of a problem caused by vapour passing through
plasterboard in the UK.

Thanks again all. I have been lucky in that my brother in law acquired
me 7 sheets of Celotex from a building site he works on today. Some
are cut, most are slightly imperfect but all are usable so I only need
to actually purchase one sheet from Jewsons to cover the entire area.

**here is the question** Can I add 50mm of wickes polystyrene sheet
above this? The only reason I say that is because I have the 50mm
polystyrene sheets lying around and will not use them otherwise. I
will still maintain an airflow above and below the insulation. I know
the polystyrene sheets cannot come into contact with wiring. Is this a
fire hazzard?

Thanks.

In article .com
, writes
Thanks again all. I have been lucky in that my brother in law acquired
me 7 sheets of Celotex from a building site he works on today. Some
are cut, most are slightly imperfect but all are usable so I only need
to actually purchase one sheet from Jewsons to cover the entire area.

**here is the question** Can I add 50mm of wickes polystyrene sheet
above this? The only reason I say that is because I have the 50mm
polystyrene sheets lying around and will not use them otherwise. I
will still maintain an airflow above and below the insulation. I know
the polystyrene sheets cannot come into contact with wiring. Is this a
fire hazzard?

You don't want airflow under the insulation, PB should be in direct contact
with the Celotex.
--
fred
Plusnet - I hope you like vanilla

On Fri, 14 Apr 2006 09:35:22 +0100, Chris Bacon
wrote:

That is a particularly ignorant statement. I have never seen
or heard of heard of a problem caused by vapour passing through
plasterboard in the UK.

You are an idiot!

Water vapour passes through plasterboard like its not there. Then it
condenses into liquid on cold surfaces like rafters and wooden sarkin
and causes rot.