On Sunday, 29 April 2018 16:44:04 UTC+1, Matt carpenter wrote:
replying to Mathew Newton, Matt carpenter wrote:
Have you considered putting 2 layers in?
Not sure on your total thickness of insulation lets say 100mm
Put 75mm under slab and 25mm above slab. Youll need a perimeter 25mm
upstand on external walls to stop the cold bridge anyway cost wise apart from
a little labour is the same just make sure slab is smooth

Cool, you can have the worst of both worlds. Not a hoh poster is it?