Wood sash windows, London.

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

  1. dwlondon

    dwlondon Active Member

    The spring is coiled inside the pipe, attached to a spiral rod which is inside the spring. as the window is lowered the spiral twists the spring and creates tension on it, which gives it the force to assist in raising the window back up.

    There are some cheap lightweight balances , which are useless and should not be bought, even if the better companies sell them. They will fail.

    Mightons have a reckoner. Which is okay if the weight of the window is close to the minimum weight given for the balance. but if its at least half of the quoted range go up to the next range. they will have enough power to lift the window.
    Deleted member 33931 likes this.
  2. chippie244

    chippie244 Super Member

    Fitted loads of sash balances and there is a knack to it, only a one man job though.
    It seems to me they were designed so that unskilled workers could install sash windows.
    Devs, I can't remember what is happening with your bro's windows but roughly if you are just changing the sashes then you probably going to have problems/expense if the existing sashes are not 45mm deep and you want d/g.
    If you want to change the box frame, unless you are in a conservation area or it's a listed building then you have to meet current building regs insulation values.

  3. Cheers - really useful info. :)
  4. So the spring type is fully hidden? No cord?
  5. Argh - forgot about bludy regs and bar locks.

    He'll be going for complete new windows as the first quote he got from a London 'Sash' specialist for a repair was criminal. I found him another London company (was it suggested on here?) who will do complete windows (engineered redwood) for the same price...

    But, yep, I guess their hands are tied - they need to fit them to regs.

    No, it's not a conservation area, I don't think. Not Grade 2 anyways.

    It's chust that my bro likes the authentic look - and the added insulation for 4 windows is worth now't...
  6. dwlondon

    dwlondon Active Member

    chippie 244 : I found it difficult fitting balances with dg units because of their weight and size. the balances need to be given a wind as they go on, and holding and steadying a dg unit with the other hand is tricky as there is a lot of pull needed for the more powerful balances. So i got my son to help. he stood in the middle on a hop up and held the sash in place and we got it done. Its considering what could happen should you drop a unit or if the balance undoes itself during the process, which can happen when renewing on older windows. generally easy enough with single glazed.

    da : you see a white plastic pipe about 15mm diameter.
  7. dwlondon

    dwlondon Active Member

    da : In general with traditional woodwork, you will always need to repair and maintain. So at any time you are faced with the decision as how much to do at that time. Sometimes you can hold things off till the next maintenance with a good fill and paint, sometimes you have to do an essential repair; as that was likely to have been held off previously and so on.

    But the truth is that at some point the decision to go dg is fairly obvious, you get older and you start to really feel the cold.
  8. And bro is older than me... :oops:
  9. Soz, DW, I still don;t know where the spring goes and whether it's visible. I haven't in person seen any sash windows with these springs, so don't know what to look for.

    I know the weight type have the visible rat's-tail cord and pulley (looks great... :) ), but how does the spring type act on the sliding sash?

    And, is spring considered 'better' than weight?
  10. dwlondon

    dwlondon Active Member

    can you remember a spinning top that you pushed down on a rod and it spun? go backinto the far reaches of your childhood (rosebud rosebud)..............

    okay as you plunged the red handle down it pushed a spiral rod into the top, which engaged with a cog that connected to the mechanism which drives the top to spin round.

    in the sash balance there is a spiral rod with a similar cog connected to the spring. all is inside the white plastic pipe. so you pull down the window it pulls down the spiral rod inside ther spring and the spring gets wound up with spring type power. that is enough to carry the window back to its closed position.

    so what you are thinking of is another type of force, so you are imagining a different type of application of spring power, that of pull and return. the force in the balance is one of twisting and untwisting. so it can all fit inside the pipe.
  11. Cool - that explains the operation clearly. Thank you DW.

    But, what is visible? Is there a slot in the sash box side for a pin from the sash to go through or what?
  12. chippie244

    chippie244 Super Member

    There is a recess in the sash side for the spring to fit in.
    Use a finger wedge to hold the sash and you can fit them single handed.
  13. dwlondon

    dwlondon Active Member

    chippie 244 : A wedge, didn't think of that at the time. But will try it. When i first fitted a dg unit the spring was that strong it flipped the unit out of my hands and it nearly wrecked a radiator. Much too risky where I was working.

    da : the balances come with a set of metal fittings which are fitted to the sash woodwork. these engage with the balance spiral rod. on the rod there is a cog which is attached to the spring. so as the window comes down or up the cog is drawn over the spiral and it rotates. this applies the potential force to the spring. so the force needed can be initially set with some extra turns on the rod. Again MIghton reccommend you use the next rating above the weight of window, and that seemed to be the best way. especially with dg units.
  14. Is the spring mounted in the moving sash's frame or in the main window frame?
  15. dwlondon

    dwlondon Active Member

    the spring is inside the white pipe. this is because without the pipe the spring would bunch up get in a mess. the pipe holds it all in place and the coiled up force is controlled. The pipe is screwed onto the top of the box.the spiral rod shows at the bottom of the pipe and is attached to a fitting on the sash frame. The rebates on the sash frames for the sash cords have to be enlarged to take the pipe.
  16. chippie244

    chippie244 Super Member

    Fit the sash, fit the staff bead, knock in a couple of wedges, 10 or so turns and job's a good un.
    Prefer cord and weight though.
  17. tommy55

    tommy55 New Member

    When i did my loft conversion i replaced existing windows with box sash windows on wights and cords but it was much easier to use spring sashes for dormer where wall was thinner and there was no space to create a box to hide the frame. In spring sash window frame is solid and thinner that is why window do not have to be recessed into cavity. Both spring and box work very similar, aesthetic difference - nylon cord replaced with spring tube :)

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice