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Community and Q&A

Raising an exterior door frame

bill4123 | Posted in General Questions on

I live in climate zone 4A and have a 44 year old, completely non-insulated slab (on grade). I have a big project coming up so I want to seize the chance to insulate on top of my existing slab. There are plenty of articles on GBA for how to do that and I’m pretty sure I can handle that part. There is one small detail that NOBODY ever talks about in these threads anywhere on the internet. My entry doors have aluminum thresholds 1-1.5″ above the slab. If I go ultra minimal and do 1/2″ rigid foam and another 1/2″ wood, I have basically no room for the flooring.

Intuition tells me I need to re-frame my entry doors to make them 1″ higher (or however much I decide). I understand the framing part but that information is super easy to find. The information I need is the threshold specifically. What should I do to lift the threshold so I can reuse my existing doors and have it be done right?

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  1. Expert Member

    Run the foam and sub-flooring through under the door frame and theshold to the exterior.

  2. GBA Editor
    Martin Holladay | | #2

    It sounds like you have a pre-hung exterior door. The aluminum threshold is attached to the jambs.

    You will need to:
    1. Remove the interior and exterior casing (trim).

    2. Remove the screws or cut the nails (with a Sawzall) securing the door jamb to the rough opening.

    3. Remove the door (jambs, threshold, and all).

    4. Re-frame the rough opening (or, if there are no structural reasons preventing you from doing so, remove some of the bottom of the header with saw cuts and a chisel) to allow the door to be reinstalled.

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