Wood sash windows, London.

Discussion in 'Carpenters' Talk' started by Deleted member 33931, Dec 29, 2015.

  1. dwlondon

    dwlondon Active Member

    what you are talking about is a glazing bar. on a trad sash it has a core of about 8mm running the thickness of the frame 35,40 or 45. off that on either side is the moulding again another 8mm or so. giving your imperial inch in effect. on the georgians it can go down to 20mm.

    now, ordinarily a dg unit has an edge band of about 10-12mm in black, which is the silicon that forms the vacuum seal and shows through the glass. put that into a glazing bar and the black edge shows. not good. which is why you see new timber dg sash windows looking a lot chunkier than the others.

    for glazing bars on dg units i make up overlay beadings and stick these in the right place with silicon mastic. this goes onto an entire dg unit in the frame. from the street it looks the same as any other house.

    equally i bury the black edge into the wood of the frame by about facing the conventional cuts and making a putty finish out of the timber frame. a joy to paint and maintain.

    once an amateur has done a basic paint job, the windows i make will look just like they have been there for nigh on a 100 years.
    Deleted member 33931 likes this.
  2. Yes, that's the 'glazing bead' I was on about. Useful info - thanks.

    Bro will almost certainly go for single glazed 'cos he's anal with things like that...

    Is this something you'd be interested in quoting for, dw? Four complete sash windows, but they'd need painting and fitting - the whole jobbie.

    Around 4-5 storeys up (top flat) in a terrace in London W2 - they would need fitting from the inside, I guess?

    I can get sizes etc if it's of interest.
  3. chippie244

    chippie244 Super Member

    Only if you tell them to do this, don't assume they will.
    Deleted member 33931 likes this.
  4. chippie244

    chippie244 Super Member

    You always fit them from the inside :):)
    Deleted member 33931 likes this.
  5. Jitender

    Jitender Screwfix Select

    When I had the front door made, I cut out a section of some internal architrave.

    I don't think they would have matched it precisely if i did.
  6. Jitender

    Jitender Screwfix Select

    I don't think this is a good economy, I'm awaiting another sample from another co, apparently they were used in an edition of Grand Designs. 5mm perimeter seal.
  7. mr moose

    mr moose Screwfix Select

    Just to put my pennys worth in, I did an Energy assessor course about 7 years ago, one thing that surprised me was that double glazing itself gave very minimal energy saving values in a home, and 10mm thick dg was practically insignificant. However draught proofing was considered important.
  8. Interesting, Mr Moose.

    That's our thinking too - his flat has only 4 windows, in an ancient Vic/Geor building with p'all insulation in the ceiling or walls.

    At the moment it's draughty as the windows rattle - and one has lost a couple of panes (no kidding - he's been using sellotape to stop it falling out altogether...)

    Appearance is everything - he wants them to look the same as original. And for such a relatively small area in each room, a DG panel will make precious little difference. What will make a huge difference is getting rid of the howling draughts :)
  9. chippie244

    chippie244 Super Member

  10. Ah, now that's interesting.

    Do the spring-type counterbalances also use a visible cord and pulley? So they look chust like weighty ones?
  11. dwlondon

    dwlondon Active Member

    The balances come in a plastic tube, which are screwed onto the frame, looking more like a pipe than a cord. For dg with balances its instantly a two man job. its just about doable with single glazed and they still need to be reasonably small. Its an altogether different feel when using them.
  12. Jitender

    Jitender Screwfix Select

    This is the sample detail, any good? :)

    A brochure and a 9mm sample are going out to you in the post.
    Construction; 3mm low e / 3mm Superspacer / 3mm. “Ultra Clear” float (12mm) with a U-value of 1.9W/m2K when filled with krypton.

    The height of the spacer, or sight-line, is 5mm, and therefore the minimum rebate required is 7mm x 17mm.

    With a 4mm low e on the inside, Slimlite Units can be "Ultra Clear" with a light transmission of 85% (as opposed to 75% VLT of a standard unit)
  13. Jitender

    Jitender Screwfix Select

    Not sure where they're getting the 12mm from (in brackets)??
  14. Yep, I didn't get that bit either.

    If they can make a DG unit that's only 9mm thick overall, then that might be a goer. I guess you wouldn't notice it was DG too much?
  15. Thanks DW. But I'm still confused. Where do these springs go? Are they visible, mounted on the frame sides and the sashes engage with them, or are they fitted inside the window side frame where the counter-weights would go, and have visible cords/pulleys going to them chust the same as with weighted sashes?

    If the actual spring tubes are visible, I know that will be a no-no for bro...
  16. mr moose

    mr moose Screwfix Select

    I have had problems with spring tubes in the past, they were in cheap reproduction sash windows and the broken ones could not be fixed or replaced easily, can't remember why now though.
  17. Jitender

    Jitender Screwfix Select

    I've just received that 9mm unit today, it has lowE to one pane than ultra clear to to other.

    The perimeter seal is a lot thinner than the other sample. LowE has a tint to it. i would say that the sight line is actually 6mm using my plastic ruler, where as the other sample is 7mm. Anyway it probably needs a whole new thread on glazing.
  18. Hi Jit, any chance of posting some photos of the DG pane - front on and at an angle?

    Cheers in anticipation :)
  19. Jitender

    Jitender Screwfix Select




    The first 2 pics are the same glass, the last one is from the first company. But you can see the greenish tinge to one glass, whereas the clear one is obvious.

    The first sample has a 3mm cavity (grey foam like material), if the cavity is increased it can be white or black. It has a foil tape applied.
    Deleted member 33931 likes this.

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