Door sill height above roof-top deck

[Michael Thomas]

Often, the installation of a roof-top deck on a flat roof raises the effective "roof level", causing an increased amount of show to pile and drift against the sill, increasing the likelihood of water intrusion and speeding deterioration of the sill, door frame, door and door trim.

Q. Is these a code requirement or documented best practice for the minimum vertical separation between such sills and the "effective roof level" below them?

[Scott Patterson]

Codes generally do not address stupidity.... This is a common sense issue that will not be specifically addressed in any code I can think of.

[Markus Keller]

Nothing that I am aware of. I always write it up as a stupid defect. Since the threshold and bottom of the door and jamb pretty much always have water damage its a no brainer.
A couple of the issues with this is that homeowners often don't want a step. Contractors don't raise it because then they would have to build 1-2 steps inside the room to make up for the height. That of course is more work.

[Michael Thomas]

There... I fixed it!

[Welmoed Sisson]

It's also possible that it's an intentional feature. I did a house that was occupied by a couple and one was in a wheelchair. All the thresholds were equal so that he could get in and out of the house easily. They were aware of the potential for water damage, but being able to use the deck and patio was more important to them. I just warned them to keep an eagle eye out for rot, and there was already some starting at one door (after only three years).

[Michael Thomas]

Unfortunately , neither of those was "intentional"...