EPDM DPM to DPC - How best to complete....?

[Mulberry View]

This is an external door installed onto XPS with EPDM as the DPM. The EPDM was left long on the inside. I turned it up at the sides in case it was needed. It's an ICF build with Waterproof concrete and no conventional DPC. It's an RK door with a skimpy low threshold, almost non existent upstand.

 

The floor is Block & Beam, there is a 1200ga DPM under the PIR, this is what you can see in the image laying back onto the PIR.

 

 

This is with the EPDM lifted. The inner threshold is 50mm below the door threshold, but still XPS. The screed needs to come up almost to the underside of the threshold, with 3-4mm Microcement as the final finish.

 

 

How should this detail be finalised? Should these membranes just be taped together? Any expansion joint along the threshold?

 

There's another 80mm of PIR to go on yet, this will bring it level with the blue XPS, with everything 50mm below final FFL. I have 2 more Norrsken doors following roughly the same principle.

 

As always, your help is invaluable to me, and I'm procrastinating on it at the moment!