Insulating a stud wall..

[ali68]

I have a 4x2 cls stud wall requiring insulation, will use either 70mm Extratherm rigid insulation or 100mm Isover glass wool.

Out of those two what would give the best U value.

thanks

 

[Deluks]

Where is the wall? Internal partition? stud wall up against an exterior wall? Up against the neighbours wall?

Anyway, Xtratherm is the answer, but if it's a party wall or dividing wall then use the Isover.

 

[ali68]

Its a dividing wall for an internal garage, foil backed plasterboard on the warm side and fire board on the garage side.

 

[^woody^]

Rigid PIR/PUR board is roughly twice as good as quilt insulation.

So same insulation value for 1/2 the thickness or twice as efficient for the same thickness

For a garage partition, you need 100mm of the xtratherm. No need for foil backed board with this insulation, nor in this situation (ie internal partition). Nor fire rated plasterboard.