Gas pipe / tracpipe under newly built floating kitchen floor

[TofuSpaceship]

Hi all
Having kitchen re-done by a builder (tearing down a wall.and new higher roof at the end)
Also the kitchen is currently a concrete paved area, floor level 18cm below the rest of the (Victorian) house, which is suspended timber.
I'm planning to do the floor myself to save a bit on costs and to have fun too.

For the kitchen floor the plan is to have a floating floor made out of:
Self leveling compound
DPM
120mm insulation slab (maybe a bit less)
Two 18mm ply boards
Optional electric UFH
screed
Tiles

a new MDPE water feed will be run from the front of the property into the kitchen, so it will need to be buried in the kitchen floor: builder said I can cut a channel in the insulation slab and lay it there, do you agree?
The gas engineer who has been round to take the boiler down, on the day he was here muttered meanwhile working that it is ok to lay the gas pipe in a (separate) channel too, do you agree? It was a day full of commotion so there are chances we misunderstood each other.
Anyway, would I just be OK in cutting a channel in the insulation slab myself, lay the tracpipe myself and leave the tails out for the gas man to finish the job?
Would it maybe need some sort of reinforcement/ducting in the channel that I cut out of the insulation slab?
The pipe would come from the void under the suspended timber floor in the dining area and then run probably two metres in the floor before coming up to get hooked to cooker and then boiler next to it.

Appreciate some advice as I'm trying to get some materials so that is at last out of the way
Thanks

 

[John D v2.0]

the gas fitters hang out on the plumbing forum so maybe better to ask there:

yes water pipe can be chased into the insulation although keep it where it won't freeze
it's ok to lay a gas pipe either in a ventilated floor void, or suitable sleeving or pipe that would not allow a buildup of gas in a void.
you probably wouldn't be able to lay the pipe yourself unless agreed with the gas fitter, as they are taking legal responsiblity (it's a criminal offence under gas regs to install a dangerous result)