Garage Conversion Query - Floor Levels

[finlaand]

Hello

I have seen partially similar posts, so apologies if this is painful repeat.

My internal garage cement floor is 170mm below existing rest of house ground floor base.
AND
That current garage slab height to start of RSJ spanning the garage doors is 2020mm.

Problem - putting in new over the counter French doors from wickes or another is not possible as not high enough if floor raised to restof house level. (I was suggested raising the RSJ but quotes seem more expensive on the solid brick wall and its changes, than getting custom doors made that are just below normal height)

HENCE - I want to put down insulation then screed, as thin a total as possible, so when I ask a carpenter to create some doors, they can be as close to normal as possible.

- I still want the floor of course to support normal kitchen things, such as heavy range cooker

ideas please? would Celotex GA4025 (50mm thick) and 50mm screed be ok, and meet regs? That would free me up 70mm - hence new doors and frame total height is 2020mm - 50mm celotex - 50mm screed - 25mm (20mm tiles 5mm adhesive) - leaves total door /frame height of 1895mm

thought most welcome, thanks all

 

[hotrod]

That would free me up 70mm - hence new doors and frame total height is 2020mm - 50mm celotex - 50mm screed - 25mm (20mm tiles 5mm adhesive) - leaves total door /frame height of 1895mm

You need to differentiate between door height and overall opening (i.e. the space needed for the frame). For instance a std ext casing for a 6'8"*2'8" door would need an overall opening of 2080mm*900mm.
50mm is a tad tight for a std screed. Don't spoil t'ship for ha'pworth of tar as they say. I would lift the RSJ and then you can have the depth of flooring / height of doors you want.

 

[^woody^]

50mm celotex wont be enough, and neither will 50mm screed

For the doors, drop the framedown a course so that the bottom of the doors are at floor height