Bay window rot project. The wood is rotted about 3/4 way back. Inside and outside pictures. The vinyl wrap at the front has been loose causing water infiltration.

What is supporting the window? Can I remove this wood w/o danger of window falling out? Is it secured around the outside in other locations?

Is it better to remove from inside?

Thank you

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  • Can you add a wide picture of the entire bay from outside? Sometimes they hang from cantilevered joists above. I don't see any supporting structure underneath so perhaps that's the case. I also don't see much support for the floor platform. If that's supposed to support human weight, regardless of how the framing is done the floor LOOKS like just a sheet of plywood??
    – jay613
    Jul 4, 2023 at 20:42
  • Hi, I added a wide shot. Just trying to figure out if it's hung by cables and/or if the bottom seat is load bearing. It is rotten about 1/2 way back. I bleive the vinyl wrap came loose a while ago allowing water to infiltrate. TY
    – Chaucer
    Jul 4, 2023 at 21:37
  • I don't think this is a DIY project. You need a crew to safely remove and reinstall the bay window. I would hire a contractor.
    – r13
    Jul 4, 2023 at 21:51
  • 1
    It seems likely, at least I hope, it's a cable system supporting a factory-made bay unit with a steel frame. Looks like there is a bolt there on the left side that is still intact? If that is, then the one on the right is .... gone? If repair is possible you'll need someone specialized. May need to replace the whole unit.
    – jay613
    Jul 5, 2023 at 7:06

2 Answers 2


Doesn't look like anything is supporting that window. Even when the plywood was new that would be insufficient. the general best practice is cantilevered joists and the bottom part of the bay window is just a box on the outside.

That's a tough retrofit though so likely a structural engineer and some steel to retrofit support.

  • It could be supported as jay613 suggested - with a cable system, or some other similar means, from the top of the opening.
    – SteveSh
    Jul 5, 2023 at 13:58
  • @SteveSh anything is possible but my bet is shoddy construction. Jul 5, 2023 at 17:35

I would prop up (jam) some posts or long bits of timber to support the frame. Then remove the timber.

However, as mentioned by @FreshCodemonger, it appears that it was never supported. I suggest that you talk to a Builder, Architect or Engineer. Pay them for an hour of their time and discuss it with one of them.

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