Door Threshold Cavity Prep

[paul3944]

Just been to a friends house where a window has been removed and replaced with French doors. The existing floor is a sand cement screed.

The new door has has left an exposed section of cavity wall along the base of the new door.

Do i lay a DPM in the cavity and screed over the cavity joining onto the existing screed?

Your help is most apprecited.

 

[paul3944]

Heres a generic pic off the internet which is similar to the problem.
Many thanks

 

[Flintstone]

I would just fill it with some concrete, ready mixed bags easily available.

 

[Slippery]

As the bricks in the outer leaf are below dampcourse, you must create a DPM (damp proof membrane) between the outer wall and the internal floor, if not, damp will track onto the floor, possibly causing the adhesive to fail.
Best practise is to create a "bathtub" with visqueen and fill with concrete or screed.
For a quick fix, if you are sure there is plenty coverage of the first course of tiles to the floor, you could fill with expanding foam and trim it flat when dry with a handsaw, as long as you understand it could be a weak spot (will it ever get stepped on? (doubt it))!