DPC question

[KAgantua]

OK I am relaying new tiles in the rear porch of my 1930s semi.
I have removed the old tiles and have hit a snag.

The external DPC is one brick above the finished slab level outside the house.
The internal DPC is one brick below that - consequently, if I lay the tiles thus:
- Concrete Screed to level
- Levelling compund (if necessary)
- Tile adhesive
- Tile
- Sealant

Then the finished floor level will be roughly 15mm above the internal DPC level.

Note that this rear porch used to be external (The internal door leading to it is my old back door) and the patio doors therein are in the gap that used to be an open archway (Now widened)

House is cavity wall construction on exterior walls, and has concrete ground floor.

Will this be a problem, or should I dig down, lay the floor lower, or something else?

[Spudler]

Assuming it's not subject to rain then no problem.

Saying that, some know-all will be along to say the opposite

[Tom_C76]

I'd be tempted to slap on a coat of paint on DPM before screeding, taking it up the wall onto the internal DPC all round. Then all your new work is inside the damp proofing.