I've been thinking about buying double glazed glass panels to mount directly into a timber frame building, rather than buy complete uPVC units. I don't need them to open and I'm wondering if it's as simple as building a rebate to hold the panel?

  • Location might factor into it, since pre made windows would have better insulating properties for cold weather.
    – crip659
    Commented May 26, 2022 at 21:26
  • Dig up a copy of the updated edition of Rex Roberts' Your Engineered House (Updated by Charlie Wing) for a detailed set of instructions if you mean "how to mount double-glazed units" - if you mean make them, well, don't.
    – Ecnerwal
    Commented May 27, 2022 at 1:26
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    Look into local building regs on what percentage of window area must be openable.
    – Tetsujin
    Commented May 27, 2022 at 6:19
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    @Tetsujin this is an unheated outbuilding which should be fine in the UK but yes good point about checking regs.
    – Mr. Boy
    Commented May 27, 2022 at 8:46

3 Answers 3


If all you need is help mounting pre-built pane units, it comes down to four simple things:

  • A recess into which the panes fit
  • Shims (usually plastic) on which to level and rest the panes
  • Suitable foam or putty tape for sealing both faces to the frame
  • Stops which you'd apply to sandwich it all

Have a glance at how commercial window installers work. It's not really complicated at all.

  • 1
    so really very similar to replacing a single pane of glass in principle?
    – Mr. Boy
    Commented May 27, 2022 at 8:45
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    @Mr.Boy If you're making wooden frames, and buying in the panes ready assembled, then treat them as very thick panes of glass.
    – Simon B
    Commented May 27, 2022 at 10:38

Compared to most commercially made double glazed you can’t make them and the reason why is the air is purged. And usually a gas that is clean and dry is filled in the void.

Why is this important? With temperature and humidity changes moisture gets sucked in to the center and a home made double glaze now has condensation inside where the purged and sealed windows look clear the home maid start showing condensation mostly at the bottom edge but as it gets worse the moisture starts rotting the wood out.

It is not hard to make them a relief on each side some glazing points and putty are the simplest add some wood to hide the interior putty and they look ok for a while but then the humidity “smile” and later the rot.

So yes they can be made but my experience was they started looking rough in 3 years and the north side was shot in ~10 years on a 3 sided 3 seasons room.

  • 4
    OP says he's buying the glazed units & just wants to fit them without pre-made frames.
    – Tetsujin
    Commented May 27, 2022 at 6:20

Presumably the outer side of the frames will have the sort of quadrant profile built in. As long as the frames are deep enough, to take both the units and another quadrant glazing bead - (the piece of wood that stops the glass falling out from one side), on the inside, which can either be stuck down or pinned in, job done. Quadrant - quarter of a circle (profile)

You could use putty, if the frames are too skinny, but I've done the above several times - it's easier when replacement time comes round - if ever. Just get good 45° mitre joints on the corners. any old strips may be needed to level, but depending on the overlap, may not even be necessary. Mastic all round if you feel it's a security issue, but then you'll use laminated glass on one side of the double glazing - won't you?

Another option - if the building is still to be built - is to find second hand units including frames - they're often available cheap at double glazing firms (mis-measures!)


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