Ask a Question

Get a Quote

Q: When installing french doors on the patio of a house with a slab foundation, how do you support the 3/4" threshold overhang?

I currently have a sliding patio door. The threshold of this door is only 3 7/8" total. This causes it to line up flush with the foundation on the exterior. However, the new french doors I'm replacing it with has a threshold of 4 5/8". So, now when I install this, the threshold will overhang the slab by 3/4". Is this ok? Does it need to be supported? I would like to do this in a way that looks professional.

Posted in Other Remodels on

patio door threshold Flag / Report


  • A: Thoughts



    It can work as-is... but I'd suggest adding a piece of Azek (or equivalent) fascia under the lip of the door to finish this area off, and to provide just a bit of support for this lip.

    Also, make sure it's well-sealed, both around & under the door, as well as around & behind the fascia.

    Best wishes!
    ~Matt

    Rating: 0
    Flag / Report

  • A: Adapter



    Most manufacturers offer a sill support accessory. 3/4" isn't too much to stick out past.

    Rating: 0
    Flag / Report

  • Answer This Question


    Create a profile or
    Login to take credit!
    May 26, 2022

    A: