Polystyrene foam eps sheets

[For want of a better word]

Skip dipped some sheets of POLYSTYRENE FOAM EPS SHEETS!
New in a pack of 6....
plus a dozen lengths of C16 4 x 2's
Asked the chap filling the skip first... said help yourself!
What townies throw away!!!!

What thickness for roof insulation.... 50 mm if Kingspan but how much for this stuff?

Chons da

 

[Newbeeneil]

PIR/PUR – 100mm

Phenolic – 90mm

EPS – 170mm

Equivalent thicknesses of common insulation boards.
Kingspan is in the PIR/PUR group.

 

[Millet]

Twice the thickness of polystyrene compared to kingspan to give the same insulation benefits.

 

[Ian123]

Given there are no air tight seals and often wooden parts between insulation and boxes I think anything over an inch of celotex or it’s equivalent it’s likely to be overkill.