Underfloor insulation for maximum headspace

[CraftyCampers]

Hi all, being 6'4" tall i'm looking to keep as much floor to ceiling space as possible. Has anyone used 10mm closed foam insulation on their floor instead of 25mm wood battens and PIR insulation board? I'd still use 10mm battens to support the floor and prevent the insulation crushing over time. Thanks in advance for any feedback

 

[Mupp3tt]

Have a look at aerogel... 10mm of it is the equivalent to approx 70mm PIR.. but it's £££
Compression isn't an issue either it works the same. Hydrophobic and can come bonded to most surfaces you would use for a floor. Next best would likely be a SIP board. These are only my suggestions to keep height.
I'm installing a hydronic floor using SiP layup. Have a look at vanlifetech website. And yes availible in the UK.