Until you reveal the depth of the chases ....
Deep enough to lay 15mm? hot water pipes. I assumed they're lagged or something so what like an inch?
There will be self levelling and a wood floor layed ontop.
Suggest you measure the diameter of the split foamed lengths of insulation, might be closer to 40mm? Also, I think that building regs call for 'protection' of infloor copper pipes. A length of 40mm interior waste pipe might suffice.
@hugo7 started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Until you reveal the depth of the chases ....