I’m building my house with Universal Design principles and one cornerstone of this is “zero threshold” door entryways.  What I’m looking for is fine level details on ways to accomplish this. So far, the best example I’ve found is a Matt Risinger video showing a completed product.

Okay, I’ve attached a mockup of what a typical entryway looks like.

WHAT’S THERE
The house is on a concrete slab on grade. All entry doors exit to a concrete patio with a minimum of 8′ overhang. The patio is raised 3/4″ above the slab!

THE PLAN
I’m planning on running the tile all the way to the patio — the tile becomes the threshold in this case.  Alternatively, I could put a “normal” threshold right there between the tile and patio, just ensuring that it’s flush with the patio.

The door will be hung on the outside and will swing out.  The weatherstripping for the sides and top will be typical but the bottom cannot since there is no raised threshold.  Therefore, I’m planning on installing a mortised automatic door bottom from PEMKO or Zero.  Those do leave gaps on the two sides of 1/8″ to 1/4″ or so, but that might be workable with some felt or something.

THE CONCERNS
I’m not too concerned about water since a) it almost never rains here in Phoenix AZ and b) the patio extends between 8′ and 10′ in front of the doors and I can’t imagine what kind of storm would be needed to get past that.  The main water concern would actually be something like pressure washing the patio… but then we’ll just have to be extra mindful.

Air sealing is a concern because I do want the house to be super tight (given some compromises).

But mostly, I’m concerned that I may be blindsided by something since I’m proceeding with scant details.

What I’m hoping for is somebody or somewhere that has detailed how to do this “properly” OR somebody even here who can comment on my plans.