The specification for insulation on my warm flat roof about to go onto my extension is for 120mm Kingspan Thermaroof TR27. This has Thermal Conductivity: 0.024W/mK and cost of £26 per sq m.
I also see insulation such as Celotex XR4120 Zero ODP Rigid Insulation Board but am not sure if this is the direct equivalent - thermal conductivity of 0.022W/mK seems better and is a bit cheaper Price per m2: £23.73/m2.
Are they directly equivalent? Placement is in a 18mm plywood sandwich with vapour control barriers and there is to be a skylight.
Could I be considering others such as Recticel Powerdeck F or others you might suggest?
The thing is I really need to get delivered within next 7 days and I am reading about a national shortage of supply so I may need to be flexible.
Help on product or supplier (to Brighton) is much appreciated.
Thanks
Scott
