Help repairing floor

[Sparky298]

Hi all, im hoping someone can point me in the right direction;

We've recently had new french doors installed which lead directly outside - but the installers have left the floor like this so im looking at repairing it myself - we are going to have dryback LVT installed so it doesn't have to be a perfect repair as they will be screeding it first anyway. But I dont really know where to start - i dont want to have damp problems after we have had the LVT installed so im hoping someone can give me idiotproof instructions on what to do.

As you can see the DPM doesn't go under the door and is loose and the cavity only has some rubble in it and that isnt even either.

Thanks in advance for your help

 

[Wayners]

I filled my cavity.

Cleaned and vacuumed out.
Lined with plastic dpm and filled with concrete.
Really should put some polystyrene insulation against outside wall but I never

 

[Sparky298]

Thanks for your reply

Did you line the void and attach it to the brick of the external wall in some way (maybe a grab adhesive) & did you just overlap the original dpm - then did you just use concrete all the way up to floor level?

If i used Kingspan in the void would i put concrete on the internal side of the void up to the kingspan?

Sorry if these are daft questions just dont want to get it wrong