Insulation - celotex or tri iso?

[Giffolew]

Basically I'm building a room at the end of the garden. Looking to insulate and have looked at 100mm celotex for floor, walls and roof. This is however really rather expensive. Is Tri Iso better/ as good as 100mm celotex? Or is there a cheaper alternative to celotex?

 

[Deluks]

//www.diynot.com/forums/building/insulating-shed-for-use-as-office-for-xbox.392341/

Celotex (or similar) wins hands down, for insulation value.
What's the price difference, and what thickness of celotex would you have to drop down to, in order to match the price of the other stuff?

 

[Giffolew]

//www.diynot.com/forums/building/insulating-shed-for-use-as-office-for-xbox.392341/

Celotex (or similar) wins hands down, for insulation value.
What's the price difference, and what thickness of celotex would you have to drop down to, in order to match the price of the other stuff?

Thanks for getting back to me,

I can get a 1.2x2.4m, 100mm celotex board for £32 or this Tri-ISO-Super stuff is £165 for 1.6x10metres.

This other stuff claims to be equalivalent to 210mm of traditional insulation but is only 13mm. It just staples on...

My room is 4.2 metres square and 2.3m tall so 100mm celotex for the whole lot is rather expensive...