For a fixed window (external, non-opening), is there any reason in principle why one could not skip having a window frame altogether and mount a triple-glazed "sealed unit" directly in to the aperture created in an exterior timber wall, perhaps with only a minimal bracket for fixing purposes?

 

It strikes me that frames are expensive, complicated, (sometimes greatly) reduce glazing area, and are designed mostly to enable windows to open. And frames also have comparatively poor U-values (even for Passivhaus windows) than the glass they contain. 

 

Problems I can imagine:

1. Sealing and ensuring water runs off properly.
2. Coping with differential heat expansion (bang goes the window on a hot day!).
3. Access to swap the sealed unit if necessary.

Undoubtedly, there must be something fundamental that I am missing. Please enlighten me.

Edited January 21, 20206 yr by Dreadnaught

I have often wondered this.

My old MGB, designed almost 60 years ago, managed without them.

They did rattle and leak though.

I think it is just a case of getting the right kind of seal.

Something like a T section. Then a L section, and the right adhesive.

 

Easy to do.  I've seen a locally built timber conservatory built this way.  The floor to ceiling glazing units were just bedded on soft sealant in a rebate in the timber frame, then capping bits of timber were fitted outside that hid the sealant and overlapped very slightly on to the glass.  A suitable gap needs to be left around the edge for movement (hence the need to use a soft sealant) , but other than than I can't see any problems, other than coming up with a way to make the inside and outside look neat.

Didn't @tonyshouse house do that with his basement windows, or something? On brick rather than timber, IIRC.Can't find it on his web site at the moment.

1 hour ago, Ed Davies said:

Can't find it on his web site at the moment.

Still there, via us:- https://forum.buildhub.org.uk/topic/10669-frameless-glazing-units/?tab=comments#comment-180111

Thought we'd discussed it before but my memory really is getting very wobbly if it was that recently.

11 minutes ago, Ed Davies said:

Thought we'd discussed it before but my memory really is getting very wobbly if it was that recently.

Discussed it over at the other place.  Joiner and RenewableJohn got together and cobbled something, up if I remember correctly.

Thanks all.

 

I've been looking online at how to seal a sealed-unit into a wooden aperture… and so have descended into the world of window putty and butyl glazing-tape and a myriad of other tapes, caulks and sealants.

 

I assume the concerns are twofold: (i) rain- and wind-proofing the exterior (including the fate of the rainwater that runs down the window); and (ii) airtightness on the interior. 

 

Airtightness I imagine is just a matter of the right tapes as with any window. The tapes then being hidden by the plasterboard in the reveal. 

 

Any thoughts on rain- and wind-proofing on the outside anyone?

Edited January 21, 20206 yr by Dreadnaught

I fitted a replacement DG unit to my wooden frame a few years back.  I made a mistake and it sat hard against the base.

The inevitable happened and it sat in some water and within a couple of years it had misted up.

When I painted the windows this year, I cut a couple of drainage notches into the external trim (just a bit of timber stuck to the glass).

The idea being that any water that gets in, can get out again.

Not sure if it will make any difference, may not find out until I change the units for new ones.

Edited January 21, 20206 yr by SteamyTea

5 hours ago, SteamyTea said:

Discussed it over at the other place. 

Yes, I'm sure I remember seeing a lot more than that hand sketch - photos of the actual windows, etc.

11 hours ago, Ed Davies said:

Yes, I'm sure I remember seeing a lot more than that hand sketch - photos of the actual windows, etc.

 

Two-thirds down the tonyshouse page the diagram is repeated and there are two photographs to the left of it with a wall with an opening consistent with the sketch