Sliding sash windows

[Stormer1940]

Just wondering how much smaller people make the width of their sash's to allow free movement when in operation (weighted not balances)?

So gap size from front of pully stile to edge of sash stile.

Thanks in advance

 

[Doug71]

Enough to allow for paint and a bit of swelling but not too much because the sashes can kind of wedge at an angle if too much clearance.

That's really helpful isn't it!

I probably tend to give them too much because I don't want them sticking, it also depends on the size of the window, maybe 6mm in total, so 3mm each side.

These days I put a draught seal up the outside of the sashes, stops the draught, keeps the sashes central and means you can give them plenty of clearance with no chance of sticking.

Doug

 

[Stormer1940]

Enough to allow for paint and a bit of swelling but not too much because the sashes can kind of wedge at an angle if too much clearance.

That's really helpful isn't it!

I probably tend to give them too much because I don't want them sticking, it also depends on the size of the window, maybe 6mm in total, so 3mm each side.

These days I put a draught seal up the outside of the sashes, stops the draught, keeps the sashes central and means you can give them plenty of clearance with no chance of sticking.

Doug

Thanks Doug much appreciated reply.

 

[Stormer1940]

Just a few more questions

Is there a standard size or rule of thumb for cutting the door length in the pocket of the frame? Obviously at the moment I don't know the weight of the sash's with glass so cant go on weight length.

How high should you set the pocket from the bottom?

Also how far down from the top should you set the top on the pulleys?

 

[Doug71]

Just looked at one I made for my house a few years ago, I put the pulleys about 65mm down from top and started the pockets about 100mm up from the cill but it is only a small window about 1.2m high.

If you go on the Mighton website there is a calculator to work out the weight of the sashes if you know the size

https://www.mightonproducts.com/weights-calculator

and this might be useful for you

http://www.timnott.co.uk/Stuff/sashwindows.pdf

Doug

 

[Kev]

Have only done about dozen or so of these but as Doug points out the Mighton site is very helpful (their products are very good as well). In terms of the pockets, from memory, I think it very much depends on the size of the weights being used. My view is the whole point of a pocket is what happens when the chord needs replacing so you need to make sure you can get access to the weights for re-stringing. If it is a heavy window (eg double glazed) then the weight will be larger and probably longer, depending on the materiel the weight is made from the pocket will need to be made to allow access to the top of the weight to tie the chord to it.

not much of an answer but hope it helps.

 

[Stormer1940]

I spoke to someone at mighton on tech the other day. When I asked about weight size etc he said easiest way is to have the weight (lead) in 2 so you have a flex in it to fit it in the pocket. The height of the big box is 1530 x 1222 and 2 smaller on sides at 1530 x 838 and it is double glazed so extra weight needed than normal. Bay window construction (3 frames with 2 no infill posts).

 

[mr rusty]

I'm currently making sashes using accoya. Stile to pulley lining clearance is 2mm /side for half the width of the stile, and 4mm for other half (i.e. either side of cord slot) to allow for a sliding seal.

I am DG with 24mm units. My sashes are weighing in at around 16kg each. I am using original cast weights with lead tops +4kg a side (in 50mm sq).

Because of the large weights, I designed my windows with the weight access through the lower section of the inner lining rather than through the pulley stile. Yes, if cords need replacing the architrave has to come off, but no big deal, and it keeps the pulley stile free of joints.

I am dry glazing with internal beading using reddiseals clip system and epdm seals

 

[Stormer1940]

Hi Mr Rusty, I'm planning on using brush pile on the parting bead and staff beads and have been told 2 to 3mm for clearance. What draught excluder are you using? Out of interest are you using the meeting stile seal that reddiseals do?

 

[mr rusty]

Hi

I'm using reddiseals plastic parting and qwood staff bead which clips in to a plastic insert.

Brush pile in parting and staff beads is reddiseals 5.5mm for gaps 1.5-2.5mm and reddiseals flexislide sliding seal down the side

My stiles are 56mm wide and the distance between staff and parting is also 56mm. However I machine a rebate 3mm deep by about 18mm adjacent to the parting bead, so the stile has 3mm overall clearance for the brush either side. Doing this also closes the gap at the meeting rails, which I'm sealing with a double pile - one on each sash.

I'm using accoya which is very stable so can use small clearances. You might need a bit more if you're using e.g. redwood.

If you look on some sash manufacturers websites you can download drawings for "inspiration"

 

[owen]

When I'm making mine I tend to make the sashes to the exact size of the internal box width and plane them down when fitting on site until they slide nicely, normally take 2mm or so off either side, but I use accoya so minimal risk of the wood moving. I use lighting for most of my beads/weights/pulleys etc too.

 

[Stormer1940]

Hi

I'm using reddiseals plastic parting and qwood staff bead which clips in to a plastic insert.

Brush pile in parting and staff beads is reddiseals 5.5mm for gaps 1.5-2.5mm and reddiseals flexislide sliding seal down the side

My stiles are 56mm wide and the distance between staff and parting is also 56mm. However I machine a rebate 3mm deep by about 18mm adjacent to the parting bead, so the stile has 3mm overall clearance for the brush either side. Doing this also closes the gap at the meeting rails, which I'm sealing with a double pile - one on each sash.

I'm using accoya which is very stable so can use small clearances. You might need a bit more if you're using e.g. redwood.

If you look on mumford's website you can download their drawings for "inspiration"

I kind of get what you are saying, but my brain works better with drawings :lol: :lol:

When I'm making mine I tend to make the sashes to the exact size of the internal box width and plane them down when fitting on site until they slide nicely, normally take 2mm or so off either side, but I use accoya so minimal risk of the wood moving. I use lighting for most of my beads/weights/pulleys etc too.

I know it's dependant on size of window but what is the cost difference roughly when done in accoya?

Just wondering if anyone has used one of these for the meeting rail https://www.reddiseals.com/product/redd ... rail-seal/ It's a Mighton copy apparently but I can't find their version on their website.

 

[mr rusty]

I kind of get what you are saying, but my brain works better with drawings

some grabs of my dwgs below

I know it's dependant on size of window but what is the cost difference roughly when done in accoya

I reckon, based on my quants, there is about £150 of accoya in each window - I'm using it for the sashes, pulley stile and outer linings. Using redwood for inner linings and head, utile for cill. which is around another £40

Accoya is expensive but IMO worth it for sashes/weather facing components. Downside is it comes rough sawn and you have to machine it. It works and machines easily but is a little brittle. I'm using Festool Dominos (10mm x 80mm) for joints.

Just wondering if anyone has used one of these for the meeting rail

considered it, but it's far too deep for me - 40mm! - it would work with a traditional single glazed meeting rail where you slot for the glass, but because I have a machined bead all round my 43mm meeting rail only has around 30mm flat surface for the two brush seals.

 

[mr rusty]

Here's some screen grabs from my working drawings which might be useful.

 

[LBCarpentry]

I kind of get what you are saying, but my brain works better with drawings

some grabs of my dwgs below

I know it's dependant on size of window but what is the cost difference roughly when done in accoya

I reckon, based on my quants, there is about £150 of accoya in each window - I'm using it for the sashes, pulley stile and outer linings. Using redwood for inner linings and head, utile for cill. which is around another £40

Accoya is expensive but IMO worth it for sashes/weather facing components. Downside is it comes rough sawn and you have to machine it. It works and machines easily but is a little brittle. I'm using Festool Dominos (10mm x 80mm) for joints.

Just wondering if anyone has used one of these for the meeting rail

considered it, but it's far too deep for me - 40mm! - it would work with a traditional single glazed meeting rail where you slot for the glass, but because I have a machined bead all round my 43mm meeting rail only has around 30mm flat surface for the two brush seals.

Have just started using accoya for external joinery - If you use the finger jointed Accoya it comes already PAR with a square edge. Just chuck it straight into the thicknesser! The time saving of not having to face and edge justifies the extra cost of the accoya imo. I haven't even adjusted my prices so we'll see how it goes.

Dominoes are great for sash windows frames. Makes life so much easier.
You do similar to me with regards to the meeting rail except I use AQ21 seal in each sash. use the panel saw to create the groove and then by having the two seals inserted in different orientation, you can achieve a nice solid cushioning seal. much cheaper than the dedicated meeting rail and much better than brush.

 

[mr rusty]

I haven't even adjusted my prices so we'll see how it goes

I'm only working on my own projects so not directly pricing. Interesting to know that you CAN get accoya PAR - it didn't seem to be available from Arnold Laver when I last bought a stock. It hasn't been so much trouble to machine as the rough sawn has been very straight!

Interesting you're using the AQ21 seal. I thought for a long time what was the best to use, and I generally discounted that style because I thought it was more of a compression seal than a sliding seal, but I can see how you might use two to gently push up against each other. I'm not seeing any issues using a double brush however - seems to be nice and tight.

As you see I'm not using any standard profiles at all - I took inspiration from one of the big commercial companies then adapted to my own dimensions. Designing for 24mm DGU and internally beading means that stock profiles are not available anyway (as far as I know) This is the first time I've taken on making windows for a whole house, but so far so good! few lessons learnt and a few mistakes along the way!

 

[Stormer1940]

I kind of get what you are saying, but my brain works better with drawings

some grabs of my dwgs below

I know it's dependant on size of window but what is the cost difference roughly when done in accoya

I reckon, based on my quants, there is about £150 of accoya in each window - I'm using it for the sashes, pulley stile and outer linings. Using redwood for inner linings and head, utile for cill. which is around another £40

Accoya is expensive but IMO worth it for sashes/weather facing components. Downside is it comes rough sawn and you have to machine it. It works and machines easily but is a little brittle. I'm using Festool Dominos (10mm x 80mm) for joints.

Just wondering if anyone has used one of these for the meeting rail

considered it, but it's far too deep for me - 40mm! - it would work with a traditional single glazed meeting rail where you slot for the glass, but because I have a machined bead all round my 43mm meeting rail only has around 30mm flat surface for the two brush seals.

Have just started using accoya for external joinery - If you use the finger jointed Accoya it comes already PAR with a square edge. Just chuck it straight into the thicknesser! The time saving of not having to face and edge justifies the extra cost of the accoya imo. I haven't even adjusted my prices so we'll see how it goes.

Dominoes are great for sash windows frames. Makes life so much easier.
You do similar to me with regards to the meeting rail except I use AQ21 seal in each sash. use the panel saw to create the groove and then by having the two seals inserted in different orientation, you can achieve a nice solid cushioning seal. much cheaper than the dedicated meeting rail and much better than brush.

Do you mind putting up a diagram of what you mean with the meeting rails and the orientation on the wiping seals LB?

I haven't even adjusted my prices so we'll see how it goes

I'm only working on my own projects so not directly pricing. Interesting to know that you CAN get accoya PAR - it didn't seem to be available from Arnold Laver when I last bought a stock. It hasn't been so much trouble to machine as the rough sawn has been very straight!

Interesting you're using the AQ21 seal. I thought for a long time what was the best to use, and I generally discounted that style because I thought it was more of a compression seal than a sliding seal, but I can see how you might use two to gently push up against each other. I'm not seeing any issues using a double brush however - seems to be nice and tight.

As you see I'm not using any standard profiles at all - I took inspiration from one of the big commercial companies then adapted to my own dimensions. Designing for 24mm DGU and internally beading means that stock profiles are not available anyway (as far as I know) This is the first time I've taken on making windows for a whole house, but so far so good! few lessons learnt and a few mistakes along the way!

The stiles and top rail I was going to make 57mm x 57mm, Bottom rail 110mm x 57mm and the meeting rail also 57mm high. Does that sound ok to you or should I be beefing the stiles and top rail up to around what you have used at 61mm?

 

[RobinBHM]

We make box sashes 7mm narrower than box size, thats using furry draught seal, 2 up each side of sash.

 

[mr rusty]

Make them how you like - all those dims are bigger than traditional single glazed sashes. You might find a 57mm meeting rail looks a bit chunky, but I'm sure will be absolutely fine otherwise - on the stiles just make sure you have enough meat for a decent joint - I found I needed a 16mm deep rebate for the DGU - 10-11mm to cover the spacer bar +5mm for the dry glazing blocks/clips.

I also cut fairly deep cord slots to accommodate cleats https://www.reddiseals.com/?s=cleat&post_type=product - admittedly I could have cut a shallower groove and just pocketed the cleat, but had enough meat not to need to do that.