Cavity insulation 100mm which type

[jeds]

I don't need any internal wall celotex with this approach though

What about 100mm celotex, I has a thermal conductivity value of 0.022 and the unilin 0.021. can't be that much different?

Celotex don't make a 100mm full fill product. It's 90mm or 115mm.

 

[Ab12]

PIR is claimed to be nearly twice as efficient as rockwool, so you should have a more thermal efficiency, over cost.

Celotex don't make a 100mm full fill product. It's 90mm or 115mm.

So 90mm 10mm gap is considered full fill then if I have a 100mm space right?

 

[noseall]

So 90mm 10mm gap is considered full fill then if I have a 100mm space right?

Essentially yes.

The difference with the Unilin (used to be called Extratherm) product is that it is rebated, so as to prevent external water travel. The fuss comes at jambs and corners, whereby you need to fit DPC....

unilin.jpg

• noseall
• 17 Jun 2023

One advantage is that you can build either the inner or outer leaf first.

You need to make sure the masonry as forensically cleaned of back-snots.

DPC at jambs and corners.

Work out how best to arrange your cuts because its so bloody expensive.

Faff about with the tie wires as you fit it.

Use a sharp fine tooth saw because the fronting plastic is not bonded very well and doesn't cut easily.

Not much fun up the gables either.

Horrible to work around the extra jamb tie wires.

 

[Mr Chibs]

Noseall, Out of curiosity, why do you place DPC in the corner?

 

[noseall]

Noseall, Out of curiosity, why do you place DPC in the corner?

Because of corner (butted) cuts. Uncut board edges are rebated. The corner cuts aren't.

 

[jeds]

So 90mm 10mm gap is considered full fill then if I have a 100mm space right?

Yes, except the 90mm Celotex doesn't reach the minimum u-value of 0.18