In article , Bruce writes
was only available (from other mfrs) with less efficient insulation while thicker ones used polycynodoodah, the exact opposite of what was required.
Well, you have o register with _a_ name, _an_ address and _a_ telephone number to obtain a data sheet ;-)
I agree with AG's position on this being nn unnecessary PITA but I will still buy Celotex seconds if they available when Kingspan ones are not or more expensive.
That sounds uber cheap, what thickness was it and was it PIR rather than another insulation? Also was it a local source or a national?
I'm looking for something thinner, to give a total thickness not greater than 25mm. I was planning to use 12mm Celotex and plasterboard, but none of the local merchants stock that thickness and a special order would involve a whole pallet. It's for a tiny cloakroom, so I only need one sheet. :-(
That's true. I wonder how many people have signed in as M Mouse?
It seems a little silly to cut one's self off from a good supplier just because of the need to register with the supplier's web site.
I agree with the principle, but does cutting off one's nose really make sense ... ?
The problem with PB backed insulation is the cost & availability.
- Jewsons 50+12.5mm PIR+PB is something like =A370/sheet inc VAT.
- Gyproc Thermaline 35mm XPS+PB is about =A337/sheet inc VAT.
Marmox is very expensive - 50mm is =A317.56/sheet inc VAT and delivery, min order 5 sheets - but a sheet is just 1200x600mm compared to
2400x1200mm for the previous.The good thing about Marmox is the waterproof cementitious coating + waterproof extruded polystyrene + waterproof cementitious coating. That means it can "catchup" with PIR+PB performance per unit thickness because you can glue it straight to damp solid brick walls and just skim it - rather than Baton thickness on top of PIR+PB thickness. For example 50mm Marmox becomes about 55mm bonded to the wall & skimmed with R =3D 1.53, whereas 25mm batons + 25mm PIR + 12.5mm PB (37.5mm K17) becomes 62.5mm for R =3D 1.15. You have to go to 25mm batons + 40mm PIR
For a ceiling, I would go with whatever the local building merchant has and screw thro the PB and the PIR into the joists.
Jewsons? =A370 ????? presume you don't have an account then
Try a local insulation specialist - 25mm foiled PIR + 12.5mm taper edge =3D =A318+VAT for a few. (It's ot rocket science - they use spray glue and bob's your insulated uncle).
not much use on the OP's bathroom celing tho
You can dot and dab PIR PB straight on without battens.
That I agree with :>) tho watch the weight if areas/pieces are large...
JimK
They do not even stock it, just XPS with PB. So it has to be special order. Bizzare.
I know, will have to hunt around.
Ah, but mention solid wall (not OP) and they run a mile. A bathroom might need care around the edge to avoid moisture.
It is surprisingly heavy.
who's "they" Jewson's numptys again?
No "mile running" noticeable here....
JimK
I just used plasterboard screws (having a large tub of them). They're only holding up the celotex for just long enough to fix plasterboard under it, which will then hold it fine.
The other thing I've done (different ceiling) is to cut the celotex into rectangles to wedge between the ceiling joists, and no fixings were required. Depends how much headroom you have and available depth of joists and allowing for ventilation.
In both cases (both bathrooms), I taped over the celotex joins (and joist edges in second case) with aluminium tape, to make a moisture-proof seal (and also used foil-backed plasterboard, although I wouldn't bother going with the pink stuff on a ceiling).
Tip - mark where the timbers are on the walls, or you won't find them very easily.
Andrew Gabriel wibbled on Sunday 22 November 2009 19:23
That's a useful tip.
Indeed :)
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