My door frame seems to be insulated well inside all around except door step that is aluminium. That aluminium piece seems lacking the thermal break, and now with cooler temperatures it accumulates condensation on the inside. I know the theory behind it warm air on cool surface, but I'm looking for a solution.

Any idea if a carbon film would help to prevent condensate from forming? Or some other film or tape?

  • quickshare.samsungcloud.com/c4KDHCIZVq4f here is the photo from inside show8ng the corner on the left side
    – Vetl
    Commented Nov 18, 2023 at 16:09
  • All information belongs in your question, not down here in comments. Please take the tour. I can't even access that network.
    – isherwood
    Commented Nov 20, 2023 at 13:53

1 Answer 1


The common term for that part, at least in North American trades, is "door sill" or "door threshold."

It seems like the best (only?) way of solving this is to replace the threshold with one having a good thermal break so that the interior surface won't be so cold. It is possible to replace a threshold without removing the door and jamb/frame. Try a search for "thermal break door threshold" to get some ideas about parts and installation.

It's possible your threshold does have a thermal break but it has been compromised somehow. You may be able to disassemble yours and check for this.

Non-vapor-permeable insulation is often used to control condensation but it seems unlikely that insulation would be practical here. I have a hard time imagining any kind of tape is going to present a surface warm enough to avoid condensation.

  • Hmmm thanks for the input. door threshold came assembled with door frame and seems like pretty attached there, so not sure if its removable(at least doesn't look like it from the high level). Well, film just would need to have enough insulation properties to not condensate. For sure it could be done with enough bulky insulation, but I'm trying to figure out if there is "slim" solution.
    – Vetl
    Commented Nov 17, 2023 at 18:20

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