Insulation - Kingspan/Quinntherm/Xtratherm

Hi,

I'll be starting a self build in the coming months - probably early in the new year.

At the moment I am pricing around various things including insulation.
I will be going for 100mm in the floors, 60 mm in the cavity walls and 42.5 mm insulated plasterboard on the external walls. I haven't really thought about the roof/attic yet. Is there much difference between the insulation options that Kingspan/Quinntherm/Xtratherm have to offer ??

I am hearing different stories depending on who I ask. I have done some searches on-line and the Thermal Conductivity of each is in the region of 0.022 to 0.023, so am I correct in assuming that with such little difference between each , my choice effectively comes down to cost ? Or am I missing out on something ?

A local builder provider told me that Kingspan or Xtratherm was the way to go and stay away from anything else - a friend of mine who recently built said the same. Another builder provider (who only stocked Quinntherm) told me that Quinntherm was the very same as Kingspan.

Any advice would be greatly appreciated, particularly around the pricing of each and if the quality of the higher price products justified it ?

Hi, i have built two large houses this year, the first a timber frame 4000 sq ft house (sealed) i used kingspan, the clients choice 100 MM in the floor,100 MM on ex walls no problems, the second property also sealed ,was polar wall construction and the client specified xtratherm 100MM on ex walls, this we did have problems with as when taping the joints with siga tape the xtratherm has an oily residue and found it a big problem getting the tape to adhere. no problems with kingspan. cannot comment on quinntherm as no experience with this product.