Filling Gap Between Floors

[B33fy]

Having had useful info on a previous question I'm back, since removing the wall between two rooms I have a strip in the floor where the wall was through which runs a plastic DPC strip and the wavy edges of the damp proof membranes, this area is about 10mm lower than the floor levels each side, I tried filling with cement but the DPM's were trapping air and springing up through the cement, all a bit of a mess.

Any ideas as to what could be used the bridge the gap before laying tiles?

Thanks

 

[Tats]

Rapid addy

 

[Tats]

A piece of 10 mm backer board

 

[B33fy]

A piece of 10 mm backer board

That seems a good idea, of to Jewsons this morning will pick some up

 

[B33fy]

Job done, thanks again