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Door threshold hight on Roof Deck: Is this a code violation?

shw001
10 years ago

There is a flat roof (about 300 square feet) on a one-story part of my house. There is a door out to it from one of the bedrooms. The door threshold is 3 inches above the roof deck. I am thinking of adding insulation to the roof and a new rubber/plastic roof membrane which would reduce the threshold height to only 1/2 inch above the deck. Does anyone see any practical issues or building code issues with such a small clearance?

We do not use this roof, except for occasional maintenance, like gutter cleaning.

Comments (6)

  • millworkman
    10 years ago

    Water is going to sit and probably leak through a door with a sill of only that height, especially wind driven rain.

  • mag77
    10 years ago

    Replacing the door with a window would solve all your concerns.

  • worthy
    10 years ago

    There's a reason not to cross-post.

    A door threshold is supposed to slope to the exterior to drain water off. However, in a cold climate you always want a much higher threshold to prevent problems with snow and snow melt on the threshold.

  • renovator8
    10 years ago

    If the insulation is to retain heat, there will probably be snow that will sit against the door. If it is to keep heat out, you need a step to stop wind blown rain.

    But 1/2" IMO is so small it will effectively be no step which is a very bad idea.

    This post was edited by Renovator8 on Wed, Sep 4, 13 at 18:56

  • shw001
    Original Author
    10 years ago

    Thanks for all the good comments

    IâÂÂve considered replacing the door with a window, but decided the door is a good convenience.

    I am not sure how wind-blown rain would be more of a problem than with the 1/2 inch step than with the current 3-inch step? The threshold is concrete and does slope pretty well and extends out about 8 inches from the door. There is also a storm door that the threshold goes under and extends out about 2 inches past the storm door. So direct rain is not likely to be a problem.

    Why would wind-driven rain be a problem? There is not likely to be puddling near the door because The slope of the roof is now 1/8 inch per foot, and after the new tapered insulation will be ü inch per foot.

    Snow is an important point. We have never had a problem before. I suspect that enough heat is escaping from the building through the brick & block walls and door that it rapidly melts any accumulation within say 2 inches of the wall and door. However, anything can happen with ice and snow. I suppose a 2-3 inch high snow or ice pile can prevent drainage and a puddle can build up behind it. Is this what you meant? If so, any solutions??

    Worthy, is there a rule about cross-posting? I just looked and couldnâÂÂt find it. If this is a problem, thanks for the warning. In the past, I have done this, if there was no interest in the post, or I realized it would be a better fit in another forum, but waited a longer time before posting in another forum.

  • krycek1984
    10 years ago

    I am not an expert, just an average person...this strikes me as a terrible idea. If we did 1/2" threshold height I would worry greatly about water and snow intrusion.