Roof Door

[vmirat]

I'm designing a new 3-0x7-0 personnel door in an existing exterior wall to go out onto a flat roof off of a second level hallway. The balanced snow depth here is 14 inches. The drift from the upper roof would make the total snow depth at the door 38 inches. I'm concerned that this door is going to leak due to the snow depth. Anyone had experience with this condition?

 

[Guastavino]

I've never thought about that. I will say though, that you could argue the same thing for a door on grade, although the Lu distance would be MUCH higher.

But more to your question. Is there clearance to step up to the door and then step back down onto the roof?

 

[thaidavid40]

We don't get that much snow in Alabama, but we do get plenty of driving rain. We always specify exterior doors with full gasketing around the head and jambs, and a gasketed threshold plate.

Thaidavid

 

[racookpe1978]

It "could" leak - probably will. I was going to say that the door would never open when there is snow around the door ... That you'd never reasonably expect some one to walk out onto a flat roof when there's snow up there. (But, that is the best way to get up topside to clear the snow off.)

The door should be 'waterproof" the same way a double-hung conventional window in the same location is "water-proofed".
Do not expect a "Code" to address every design issue.
Use your judgement and do NOT want a "Code" to tell you how to design every situation.