talk box sash windows

Discussion in 'Carpenters' Talk' started by Mr Rusty, Nov 3, 2016.

  1. Mr Rusty

    Mr Rusty Screwfix Select

    OK, I'm leading up to soon making the first of 8 box sash windows from scratch - nice little challenge :) I've been reading up, watching vids and realised there's more than one way to skin this cat.

    Long story short, the design will basically be as that of a fairly well known London company who kindly make all their drawings available as CAD downloads! - I'm going for dry double glazing, beaded inside, just like theirs. draught strips very similar (thanks reddiseals) However, I have a couple of ideas of my own I'd like a view on......

    As the pulley lining is a bearing surface for the sliding sashes, I'm thinking of facing the timber for this section with gloss white laminate rather than just painting it - should still be able to router the groove for the parting bead etc just the same and I figure a laminate surface is weatherproof and a darn sight harder wearing than a painted surface. I can easily make a jig to machine out for the pulley housings.

    As I'm double glazing, I'm going to need big weights. Dont really fancy cutting long weight pockets into the faced pulley lining - it becomes a fairly unsupported section secured just top and bottom and held in by the parting bead, and to me just doesn't seem a good idea to cut a section out of the bearing surface that can then distort/become loose/etc. - even if it is the traditional way of doing it. I think I will make the inner lining in two pieces so the bottom can be removed - only needs one simple joint part way up which should be near invisible, and this section will be nice and secure T&G'd on to the pulley lining and outer box lining. The joint can be a mitred butt joint to hold the top edge in, and the bottom can be screwed in behind the inner cill.

    Any thoughts or comments on these ideas?

    Oh yes,and before anyone asks, some parts of the original frame will be retained so it's a "repair" and not a complete new window....fensa and all that.......;)
    Last edited: Nov 3, 2016
  2. KIAB

    KIAB Super Member

  3. dwlondon

    dwlondon Active Member

    Just follow the traditional way all in timber. Its had at least 200 years proven worth. Water can still get in through the brickwork and soak into the frame, if the laminate is chipboard it will blow in no time. The way to keep sashes sliding nicely is to use candle wax on pulley stiles. Cut the weight pockets as per tradition.

    I make double glazers into original boxes and use lead weights. If there is no leaf in the box the ends need to be bevelled so that don't get caught on each other.
  4. chippie244

    chippie244 Super Member

    The sashes shouldn't be rubbing on the sides as there should be 3mm clearance, no need to reinvent the wheel.
    Sash windows came in some time in the 1700's.
  5. Mr Rusty

    Mr Rusty Screwfix Select

    Y. Considered and discounted. What is simpler and more elegant than a counterbalanced weight?
  6. Mr Rusty

    Mr Rusty Screwfix Select

    Hi chippie. Y agree but some of the makers of sash windows that incorporate draft proofing seem to be using a spring seal that takes up that 3mm which seams a good idea. And inevitably even if the gap is equal the sash will rub one side or the other. They didn't have plastic seals in 1700.

    DW no chipboard! Thinking about laminating to timber.

    I don't buy this always do it traditionally arguement because we have different tools and different materials available now.

    However I welcome your comments. All useful
  7. dwlondon

    dwlondon Active Member

    Have you seen laminating done in exterior situations?
  8. chippie244

    chippie244 Super Member

    The draft proofing that I used to fit had pile on the staff bead, the parting bead, the back of the front meeting rail and on the top of the top rail on the top sash.
    The sash may touch the sides but it isn't being forced against it so negligable friction.
  9. Mr Rusty

    Mr Rusty Screwfix Select

    DW. Yes. HPL is used for many exterior products. E.g. laminate is just fine externally.

    Chippie. Yes going to do all that. Mumford's for example also use this spring plastic seal down each side of the jamb. I wasn't thinking about the friction so much as using laminate to provide a more durable bearing surface that won't wear away like paint. But take your point. Might be over thinking this!
  10. 2shortplanks

    2shortplanks Active Member

    I think lead weights are the way to go for dg sashes, not sure how long iron weights would work out. 2 little suggestions though, make cut outs at the bottom of the outer faces so that water cant sit in the corner on the cill, and use cups and screws for one of the staff beads so you can get the beads out easier. I'd be wary about trying to reinvent the traditional design - it works really well. Nearly all the ones that that I've had to replace are because of lack of painting, and sometimes badly bowed timber. If you look after them they'll last a century or two no problem.
  11. chippie244

    chippie244 Super Member

    I agree with the cut outs as this is always where the cill rots.
    I think the cup and screws would look awful, I just run a stanley knife to cut the caulk seal and jimmy the bead off, don't put a panel pin close to the top or bottom though.
    Make the box and sashes out of good quality timber like Douglas Fir rather than a fast grown whitewood or hardwood.
  12. 2shortplanks

    2shortplanks Active Member

    The inset brass ones look quite neat.
    Re using laminate, I wouldn't. If the sashes are too tight/loose, it's often because the sides have bowed, and putting laminate on one side would probably make the timber more likely to do this if anything. Definitely worth sourcing some good quality joinery grade timber.
  13. Mr Rusty

    Mr Rusty Screwfix Select

    Thanks that's an interesting thought. I might laminate both sides of the pulley lining to balance. I do like the idea of a hard gloss white durable surface. with the pulley lining tongued in to the inner and outer linings it's going to be very rigid. I'll be using 34mm thick. Timber will be coming from my local builders merchant cw berry at leyland who have a long established joinery shop making windows. Went asking them for advice and they showed me that all the painted windows they make are redwood and although they stock a wide range of sawn timber they recommended that as good compromise in cost, ease of use and performance. If it's good enough for them it's good enough for me. They did recommend hardwood cills though
  14. sospan

    sospan Screwfix Select

  15. Mr Rusty

    Mr Rusty Screwfix Select

    Thanks sospan - good links. No idea whether that recycled plastic timber might work - can it be machined? or is it made with a finished surface and foamed core? But not far from me, and could be an interesting product for other projects.

    Also the trend link - the window system is for spindle moulders which I don't have unfortunately. I looked at them a while back, but in the end decided a router and table would be a better bet. I have a Trend T11 and CRT3 table.

    No, I'm not sure about the laminate either, which is why I put it on here to get reaction. Lots of "not sure" "probably" "might", so at the moment I probably "will", at least on the first one, because I like trying new ideas.

    Even turning the sash moulding round, machining the "putty bead" and the using dry glazing and beading internally is hardly "traditional", but its the way Mumfords do it, so it's got to be OK. Yes its an interesting project - want to keep the place looking very close to how it was when built, but have to make allowances for modern heating, insulation etc. I'm sure I'll make some mistakes along the way, but research is showing me there are so many opinions. e.g. I've decided to dry line the external walls with insulation backed PB following this project but others advise renewing the lime plaster, using hardwall plaster, and several other alternatives. This also works for me because I can make a reasonable job of skimming plasterboard myself. Choices!
  16. sospan

    sospan Screwfix Select

    No problem.

    I have see the "plastic" wood being machined and sanded there was a recent episode of "this old house" where Tom Silva made some exterior moulding out of synthetic wood. Obviously depends on the quality of the material.

    I am quite interested in the Trend systems, although probably there are others out there. I have a building plot with plans drawn up for a house with a combination of 62 windows and doors. The thought of paying for these to be made in a factory doesn't appeal as I could probably buy the machines and churn them out myself

    Always worth prototyping things like this, as you say the first one is going to be experimental and enable you to refine your techniques and materials. The only tedious job is going to be painting them - done so many in situ as a young boy never want to do it again
  17. Mr Rusty

    Mr Rusty Screwfix Select

    One good thing is the windows that are there and the original architects drawings from 1902 show sash windows without glazing bars - full panes, so that makes life easier.

    I hate painting - seriously thinking about getting one of the wagner decent spray guns to help with all the painting. I can paint windows before I install them.
  18. sospan

    sospan Screwfix Select

    Quite often when I making cabinets and units, I will "finish" them before assembly then just touch them up once installed
  19. chippie244

    chippie244 Super Member

    Georgian windows tended to have more glazing bars which reduced during the Victorian era and yours are very late Victorian so that fits.
    I would strongly advise against putting laminate on the side walls, you are solving a problem that doesn't exist and potentially introducing ones you haven't thought about.
  20. Mr Rusty

    Mr Rusty Screwfix Select

    Y I am wavering on this idea of laminate sides. mumfords use a seal that looks like this down the side of each sash that obviously runs in contact with the pulley stile. My thought was to make a slightly more hard wearing bearing surface. If its just painted I think the seal will wear through the paint surface quicker.

    It's just an idea. What problems do youi think there might be? Maybe it really is a daft idea, but no-one has actually given me any solid reason why it wouldn't be beneficial - no need to repaint the part of the window that gets the most wear?

    Not trying to reinvent the wheel, but this particular design is already an adaptation of tradition with the weather seals etc.

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