Sub floor over conc. base: Any suggestions?

[Draughtsman]

I treated the conc. base with sikka rapid dpm, then put membrane or damp course under the stud soles. I'll cover the whole base with a taped seam membrane anyway.

I was thinking of masonry screwing a couple of treated 38x63 CLS down flat directly on the membrane at the base of the stud wall to the far right of the french doors, another 400 out from the 1st. Then using low profile Stratarise (https://stratarise.co.uk/) as I progress leftwards, with 47x75 kiln dried sawn laid flat on the pedestals.

18mm hardwood ply over the joists, click vinyl over that

The tapering strip of upvc make-up along the btm of the sliding door shows that it's a bit tight at one end.

Is it worth considering stainless conc. screws to resist corrosion? I don't want any significant weight applied in one place to make the floor spring up somewhere close by.

Thoughts gratefully recieved (usually, you know who you are).

Dain

 

[foxhole]

I would be concerned about the external level car looks like it’s parked on slabs higher than internally which can lead to damp problems .

 

[Draughtsman]

I would be concerned about the external level car looks like it’s parked on slabs higher than internally which can lead to damp problems .

Thanks,
Slab run off isn't an issue, and floor level is higher internally.