sash cords and parting beads

[Fred Page]

This is my first attempt at replacing sash cords. I've looked at several internet videos but all skip over the difficulty of first finding the pockets (hidden by over a 100 years' of paint), removing these covers and dealing with the parting bead. Everything else appears straight forward.
I'm only doing the lower window frame so my question is this: presumably it's only necessary to remove the length of parting bead covering the the pocket - this I'll have to do by chiselling it out and replacing with new?
I'm tempted to strip off the old paint as a means of finding the covers but am fearful of using a hot air stripper on old paint in an ancient frame! Getting out the parting bead seems to me to be the most difficult part. Anybody any suggestions?
Fred.

 

[Jacob]

The parting bead is in one piece and needs to be removed in one. You might have to burn off a bit of paint to loosen it.
You might be able to see the sash pocket join better if you do something like shining a torch along the surface and looking for irregularities. Or a metal detector might show you where the screw is. A rare earth magnet makes a better metal detector than the gadget, for metal not very deep. Steel only.
Occasionally sash pockets are in the inside lining so if you can't find them you may be looking in the wrong place.
If you are replacing any you might as well do the whole lot - and clean out the bottom of the sash box, where dust and debris tends to accumulate

 

[petermillard]

...Or a metal detector might show you where the screw is....

They have screws :shock: Seriously, I've never come across a sash pocket cover that was screwed in place.

Also, if you're just doing the lower sash, then you leave the parting bead well alone. Run a blade down the edge of the staff bead to minimise the damage to the old paint, then lever this away with e.g. a paint scraper - you can sometimes get away with just taking off one side, btw.

Cheers, Pete

 

[RogerS]

That's not always the case, Peter. Sometimes the pocket is behind the parting bead.

 

[Jacob]

...Or a metal detector might show you where the screw is....

They have screws :shock: Seriously, I've never come across a sash pocket cover that was screwed in place.

Very common. Becomes essential eventually when the pocket doesn't lie flat for one reason or another

Also, if you're just doing the lower sash, then you leave the parting bead well alone. Run a blade down the edge of the staff bead to minimise the damage to the old paint, then lever this away with e.g. a paint scraper - you can sometimes get away with just taking off one side, btw.

Cheers, Pete

You can't usually remove the pocket to access the weight, without removing the parting bead first.
Levering off staff beads - insert two wide but thin scrapers in together one on top of the other and insert a fatter wedge of some sort between them. This protects the edges as you force it off.

 

[petermillard]

Very common. Becomes essential eventually when the pocket doesn't lie flat for one reason or another

Interesting, thanks. As I say, never come across this.

You can't usually remove the pocket to access the weight, without removing the parting bead first

Again, interesting - never had to do this, they simply lever out. Are there London- specific patterns for sash windows do you think?

Pete

 

[RogerS]

I think that it depends on the size of the weight which, naturally, depends on the size of the window. If the window is relatively small then the width of the weight will be that bit smaller and so possibly fit within a pocket that is the same width or smaller than the sash frame. As the size of the sash increases, you need a wider pocket to accommodate the extra lead weight. I know you can go longer but that can limit the overall movement up/down.

I guess that also it will depend if the windows are wide ones or tall skinny ones.

 

[RogerS]

Oh and whether they weights are cast iron or lead.

 

[Phil Pascoe]

I've seen them where both weights were reached through the inside cover, the downside being that the inner weight needed to be taken out to reach the outer one. It's probably more weather proof, though. When I replaced the parting beads I did it in two halves joining them just under the bottom of the horn on the top sash. This was useful on the occasions that I needed to take both sashes out, as I didn't need to wreck the waterproofing of the lower half of the window to do it. I've not seen a downside to doing this, nor have I seen it done anywhere else.

 

[RossJarvis]

I'm currently "doing up" some sliding ashes and recommend being bold. If you need to re-string a sash and there is other stuff doing, decide to refurb the whole lot, don't "fanny" around. If you need to get the parting bead out, it's best to take the whole thing out in one go. It's very easy to buy it new, not all old sizes are covered ,but with luck you can use it all again.

Firstly, take out one side of the staff bead. Using a sharp knife, cut down the inside join and the outer line where it meets the frame. Lever it out using a pallet knife and jemmy (carefully to avoid b*******g up the frame). Next, undo the knot holding the cords to the sash or cut the cord off. Pull the sash out. Grip the parting bead firmly and rock it back and fro, it may be worth cutting the paint join with a Stanley knife. generally it'll break or come out in one go. If that won't get it out, you'll need pliers and a new bit of bead, I'd never splice new bits in. Then remove the outer, upper sash. If you can't find the hatch by now you'll probably need to strip paint to find them, there's always the possibility there aren't any. I've found that a hot air gun is pretty safe if it's not held anywhere too long. If you feel you need to keep it going on one spot for more than 2 seconds, that's too long.

The point I'm trying to make is that there's no quick easy solution, unless you're really lucky. If you want to re-string a sash, you may as well take the whole lot apart and repaint everything. Hot air stripping is generally fairly safe as long as you use the lower setting on the gun. If the paint won't burn off easily then you need to use another method, not more heat.

 

[deema]

If you are doing up an old window commercially, a good enhanced value can be achieved by offering to also draft proof the window by adding weather strips. You will then need to take out both sashes out and it's also a good time to suggest getting the windows stripped, re glazed with micro double glazing and re-painted. They then need re-weighting.

I'd remove the glass and them get the sashes dipped which is far, far easier. Weak, crumbling joints get the West Epoxy treatment. When the sash is stripped it of tens comes apart really easily making weather strip adding a doddle.

So a low margin job can end up with a good bit of work. The client then gets a nice double glazed window, freshly painted with minimal drafts. That seriously enhances their living experience with it. You will often find that if you do one window, you will do all the windows / houses close by. It's a nice autumn / spring job.

 

[petermillard]

Thanks for the info re the differences in the sashes guys; all my sash work has been on Victorian London terraces, so pretty much all of one type; interesting to hear of the differences. I guess the burning question for the OP is - what's type of property/sashes does he have??

... and re glazed with micro double glazing and re-painted.

How effective are these micro double-glazed units Deema? Never used them, but one of the comments I've had from customers In the past is that they tend to get an increase in condensation on the windows after they've been refurbished, as they now much better draught-proofed. And yes, I agree, a full refurb is quite an easy up-sell to customers

Cheers, Pete

 

[deema]

The ones I have used are the units that are approved for used listed buildings. They have the same thickness (well nearly) as a single pane of glass and therefore don't need any changes to the rebates. From a user perspective they eliminate condensation, as once you have draught proofed, condensation on a single pane is significantly increased. So, in all I would say that the customer is normally delighted with the results, has no condensation, no draughts to really speak of, and if it's in the room they use a lot they actually notice its warmer and easier to heat up.

The double glazed units are very exoensive. However, if the sashes are out of thick stock and not the delicate units, you can use standard double glazed units with nominal air gap and just sink the rebates deeper. I have done this once and decided to put a dowel through the notice joints as I did not strip them down and was concerned that the additional weight may cause the joints to fail.

 

[RogerS]

Is there really any point in fitting such a double-glazed unit ? Surely the u-value is pretty non-existent in terms of energy saving. Are you talking about Slimlites ?

 

[deema]

Hi Roger,

I'd have to look back, it's been a while since I did any to see what the company was called. The manufacturer has a patent on the window system, and it's been featured in Grand Designs once I believe. If memory serves the u value wasn't too bad, and I think it was 2,2,2 finished. Special glass, coated and filled with some exotic gas if memory serves. Really lovely units, but you had to measure at least three times before ordering.

 

[RogerS]

Yup..sounds like Slimlite. Bloody expensive and u-values not that great. Sound insulation not much better. Thick heavy drapes beat it hands down !

 

[Fred Page]

My grateful thanks to all who replied to my original problem above. With the confidence gained from all your contributions I’ve made a good start on the job and look forward to a successful completion. As I child I frequently watched my father doing such work never realising I’d need such skill and knowledge (and help from people like yourselves) later in life.
I split the parting bead but this will be replaced with new stuff. Presumably one doesn’t fix this, it just being a dry fit? I can just about see the outline of the pockets but intend stripping off the paint before going further. Thanks again to all above.
Fred

 

[StevieB]

Pin the parting bead at least - very easy to remove with pincers or similar later if necessary.

Steve