compressible bulb (cylindrical) weatherstrip for 1930s casement windows?

[mrodent]

Dear all,

I wonder if anybody's got any ideas about this (or whether something similar has previously been discussed)?

I have a 1930s semi with virtually all windows being casements. All are the originals: wooden (single-pane) casements and fixed frames dating from the 1930s.

I have ordered and had delivered a set of LandVac vacuum-glazing (double glazing) panes for about half of the 40-odd casements in the house. My plan is simply to replace all the single panes with these new ones. The thickness is slightly greater, and I have prepared a first small casement, by taking the casement frame out, taking the pane out, and then hand-chiselling to make the rebate of the casement slightly deeper and slightly larger. I'm quite happy to do this casement by casement by myself over coming months.

What has been messing with my head now for a few months is about the best way to weather-proof (and noise-proof) the gaps between the casements and the fixed frames into which they fit. Since the 1930s, due to movement, some of these gaps have become bigger than others but none is really enormous. It'd be nice to have a sealing system which provides some kind of flexibility as to gap sizes though.

I have a router and I was thinking about removing the single pane, routing a groove, fitting the vacuum pane, and pushing Aquamac 21 weatherseal into that groove. I've been dithering about this for a couple of months. Part of my reluctance is due to a wish not to mess up these venerable old casement frames.

But in addition to that I have a suspicion that a more intelligent answer may be possible: do no routing, but take advantage of some existing grooves present on the casement frame and the fixed frame. These are matching grooves which have existed since the house was built. They are quite shallow curved grooves, maybe 4 mm deep at deepest, which face one another when the casement is closed. They are about 6 mm / 1/4 inch across. On one forum a few months ago someone recognised what these were, and their original function/name, but I've forgotten.

Anyway my idea is to put a suitable, above all compressible, rubbery cylindrical tube into one of these grooves, probably the one in the fixed frame: the idea is that that closing the casement would meet with some degree of resistance, but hopefully this would produce a good thermal and acoustic seal.

There are two questions:

1) does anyone have any idea about whether such tubes are manufactured? they'd probably have to be quite small diameter, maybe 6 mm diameter... and they'd have to be squashable but reasonably elastic, i.e. able to spring back. They'd also have to be reasonably tough. Although in practice most of these casements remain closed from one year to the next.

2) if they can be found, does anyone have any idea about how these tubes could be attached into the bottom of this shallow groove? My idea is to make 2 holes, one on either side of the tube, at maybe 5 cm intervals and then drill into the frame (i.e. at the bottom of the shallow groove... and then use some sort of small-washer-and-screw arrangement to keep them in place. I wouldn't really have any faith that adhesives would do the job. But maybe there's a better way?

Thanks

 

[HOJ]

Be interesting to have some pictures, are the casements flush fitting, presume so because the stormproof window didn't appear until the 1950's.

Not really answering your questions but the grooves you mention are called capillary grooves, which in theory equalise the air pressure around the casement and frame rebates to help keep any water/moisture to stay out, you would be best try and keep them for that purpose, adding any draft proofing separately.

 

[Ollie78]

I would say just buy the AQ21 router bit and use that, it works a treat and you know it will fit straight in. You can fit the AQ21 in a saw kerf but the bit takes a little extra shoulder out which is nicer and allows a smaller gap.
However, if you know the size of the groove and gap then go on the Schlegel website and see what you can find, the range is vast.
I know there is other companies as well but forget the names, I spent ages trying to find a specific seal for my old plastic french doors.

 

[mrodent]

Be interesting to have some pictures, are the casements flush fitting, presume so because the stormproof window didn't appear until the 1950's.

Not really answering your questions but the grooves you mention are called capillary grooves, which in theory equalise the air pressure around the casement and frame rebates to help keep any water/moisture to stay out, you would be best try and keep them for that purpose, adding any draft proofing separately.

Thanks. Will get some photos tomorrow in daylight.

You say "in theory". Do you think this works? Intuitively it doesn't sound all that plausible, but what do I know.

Googling on this, I understand why you'd have a capillary groove on the underside of a external window sill, but I'm a bit more puzzled by such grooves in this context. Plus, wouldn't this rubbery cylinder itself function as a block to moisture?

Wouldn't the ability to help wedge the compressible rubbery cylinder in a groove (both sides, i.e. in the casement frame and also in the fixed frame), even with a shallow groove, help with the mechanics? I mean, if the cylinder is not lodged somewhat in the grooves (both sides), won't it have to be attached more securely to prevent it being yanked sideways when opening/closing the casement?

PS the casements do have a profile with a kind of small "stormproof lip", which seems to be quite effective at helping to prevent water ingress. They probably don't count as "stormproof windows" as such: I'll show some photos tomorrow.

 

[mrodent]

I would say just buy the AQ21 router bit and use that, it works a treat and you know it will fit straight in. You can fit the AQ21 in a saw kerf but the bit takes a little extra shoulder out which is nicer and allows a smaller gap.
However, if you know the size of the groove and gap then go on the Schlegel website and see what you can find, the range is vast.
I know there is other companies as well but forget the names, I spent ages trying to find a specific seal for my old plastic french doors.

Thanks.

I have a few metres of AQ21 and a router bit which should be suitable. The thing about AQ21 which surprised me a bit is that although it feels very tough, it doesn't seem all that compressible.

Other Schlegel options: the problem with "bubble compression joinery seals" (as they are called on the Schlegel site) is that you still have to rout a groove: I'm wondering whether there isn't a way of not having to do any routing. Routing a groove is an irreversible step, and I'm not too confident that I could produce something all that professional. Plus routing at the bottom of the capillary groove would no doubt be even harder.

But there are other Schlegel ranges, as you say. For example, I look at something like this:
https://www.sdhardware.co.uk/draugh...-sp63-compression-weatherseal-black-250m-coil

or this https://firewise.co.uk/product/schlegel-aq63-aquamac-63-seal/ ... seems to be more compressible, with good elastic "memory". But, like the rest, has a "keel" and is intended to fit into a routed groove.

... maybe there is some kind of strip product which is ideally suited to my situation, and which might be able to sit in the capillary groove, and be attached by a means other than a "keel" of a strip inserted into a routed groove. I'd kind of like to feel the different varieties to get an idea of what might be best: seeing them on a website I can't really tell what's best, or what texture they have. Hence this question really.

I've just had another thought: what about some "corner strip", which fits into the corner of the fixed frame: then when the casement was closed, this would squash this corner strip (also this would not interfere with the capillary grooves). I just checked my windows: if such a product exists it could be suitable for my windows. How might such a corner strip be attached to the frame, I wonder? Screws maybe? Also it would have to be very thin and/or very compressible: at some points the gap there is as much as 3 mm... at other points it is less than 1 mm. Hmmmm.

 

[Ollie78]

The 21 is a wiper and / or compression seal, the 63 is a compression seal.
When using the 63 which is normally in the rebate of the frame you are reliant on the compression privided by the fit of the window or door and the force applied by the handle or lock.
If you use the 21 in the casement rather than the frame ( it can be used either way ) then the shape of the "flappy bit" allows sealing sideways which does not rely on compression, this is good for any application where everything is not flat and true. Make sure you use it the right way round so as it closes the closed part is moving towards the frame.

The corner strip you might be refering to is called accoustic corner seal, it does work well but you must have the right sort of frame. I have used it quite a bit, it has a stiff plastic backing with pressure sensitive adhesive, the seal bits are soft rubber stuff.
Another way is to use 3 x 8mm self adhesive plastic track and the use a brush seal, this can be good because the brush comes in 3 sizes for different gaps. See Reddiseals website.