10 or 12mm PIR insulation board

[Jdwood38]

Good morning all,

I have asked this question in the narrative of a separate thread but I suspect it will be missed and I could really do with an answer.

I am seeking a 10 or 12mm PIR insulation board to use to reduce cold bridging in a space where there is little room for a reduction in head height as well as reveals around a couple of Velux windows. Celotex used to do a 12mm board in the form of TB4012 but this appears to be discontinued with their thinnest offering now 20mm.

Could anyone please advise of possible alternatives?

Many thanks.

 

[Mr Chibs]

Only thing I can think of at 10mm+ is XPS insulation boards or STS boards.

Not sure how cost effective it will bet depending on area you are doing.

 

[Jdwood38]

Only thing I can think of at 10mm+ is XPS insulation boards or STS boards.

Not sure how cost effective it will bet depending on area you are doing.

Thank you.

Any reason why XPS wouldn't achieve the same objective as PIR? Vapour barrier will be in the form of foil tape before this layer so hopefully no issues there. It's a dormer room over a garage so not a huge space. This would only be used on ceiling (with 120mm PIR between rafters above it) and on pitched room section (with 100mm PIR above).

 

[Mr Chibs]

I don't think XPS is quite as good as PIR. (others may confirm)

If you can spare the room I'd use 20mm PIR, it's double foil backed and can be taped-up to form a VCL, it's probably cheaper as well.

 

[jacko555]

If you really need the 10mm, then perhaps the 10mm STS tile backer board https://www.sts-uk.com/tiling-preparation/professional-tile-backing-board , as per @Mr Chibs suggestion

Thermal conductivity 0.034 Watt/mK. For comparison, 20mm of celotex is 0.022W/mK.


[Edit]

Fastwarm® 10mm XPS Insulation Boards

Our XPS Insulation boards are designed for use with Fastwarm® electric underfloor heating systems on substrates consisting of concrete or

www.fastwarm.com

XPS is 0.035W/mk. So get the cheapest

 

[oldbutnotdead]

Have a look at Marmox- can't remember the U or R values but it's much better than plasterboard, def available in 12.5mm and thinner.

 

[RandomGrinch]

Edit:
Apologies, the TP link I posted had a misleading product description