filling door threshold cavity

[jjimjam]

I'm about to lay 120mm celotex on this floor, ready for ufh and liquid screed to be poured. How should I support the new insulation & screed above the cavity in this doorway?

It used to have suspended timber type floor on it, but I have removed that. It's a block & beam base and the cavity void is about 20cm deep. There is rubble/mortar at the bottom.

many thanks for any help.

 

[RandomGrinch]

I am no expert, so feel free to ignore
I think you can fill it with anything you want (well probably NOT anything ) bricks, blocks etc.
Just don't bridge the DPM or DPC.
Even then, you might be surprised at the rigidity of the celotex, that will probably need very little, or no support over a gap that small.
But, that's just my opinion!

 

[jjimjam]

Great, many thanks for the reply. I have already filled it and not bridged the DPC. DPC is at level of bottom of door frame, and runs under it.

The screed level (and flooring) will be higher than the DPC though. Do I just run DPM up the wall and door sill and cut off a floor height?

 

[RandomGrinch]

Basically yes. If you can bond the DPM to the DPC, that would be better.
If you have a Google image search for 'beam and block flooring threshold details', you should find plenty of details like:

Hopefully they will put your mind to rest!