Duplex casement windows vs 'traditional'?

[Welshcake]

We currently have very poor single-glazed wooden windows in our 19th Century stone cottage, that are not the originals (were fitted in the 80s I think.... although 'fitted' is being very generous!), and leak as they are so rotten, not to mention the howling draughts. We have now decided to replace them, so have been looking at cottage-style hardwood wooden double glazing.

However, we have been given two options by several (local) window companies of either 'traditional' casement windows, with the resultant thick glazing bars (to comply with regs and to hold in the double glazed units), or a 'duplex' system whereby it is one large pane of glass with stuck on glazing bars. The latter do seem to look the part (unless you look very closely), and it means that the glazing bars are not as thick... but as novices in the window department, we don't want to make an expensive mistake and put in the wrong windows for our cottage.

Does anyone have any advice re the merits/pitfalls of either option?

Any advice greatly appreciated!

 

[Tom]

A lot will depend on the CO if your house is listed.

Many people here, myself included, would deride double glazed units of any description. Can you not replace 'like for like' and go for single glazed units?

Jaqy

 

[worms]

Many people here, myself included, would deride double glazed units of any description.

Jaqy, I think we need to know more about the building in question before ruling out all dg options, particularly if the building is not listed (as would seem likely, since there is no mention of the CO's involvement).

The casements in my own house are about 60 years old and are local "artisanal" joinery. They are over-engineered to the point that they could easily take dg units instead of the current single glazing, with no outward alteration to the appearance. If I could afford to get them fixed up, I would have no hesitation in getting them double glazed - some currently have secondary glazing and the difference in performance is very noticeable (although the appearance suffers).

Other experts on here will be able to put me straight, but I would imagine that the fashion for very fine glazing bars and maximising the glass to wood ratio might have by-passed many of the poorer rural properties, where costs, quality of materials and the skills of the local joiner dictated what was achievable. It may therefore be that thicker glazing bars and dg would be perfectly acceptable in the original poster's situation and be in keeping with the house itself.

I would however, happily join you in deriding "stick-on" glazing bars!

 

[Penners]

Many people here, myself included, would deride double glazed units of any description.

Not me!

Double-glazing is excellent for saving energy and money. The trick is to try to fit it in a period property without ruining the character of that property.

 

[Welshcake]

Hello again. Thanks very much for all your posts. Our cottage is not listed, so no CO involvement, and keeping the current windows is not really our preferred option as a) they are all different (not in a good way) as someone has shoved in whatever they could find in a reclamation yard by the looks of them, and they have been patched up with all sorts of materials/glue/filler to make them fit the spaces, and b) some of them are so rotten we can stick our fingers through the holes. Plus, and I know this isn't very sympathetic of me, we would like the benefits of double glazing to save on our oil bill and also reduce condensation, noise etc. The house is a stone cottage in rural Wales, and we want to fit similar style windows than the current ones, and in keeping with other cottages in the area and era, but better quality!

 

[shelli]

our windows were all replaced with the type 2 you describe where it is one DG unit with fitted on glazing bars - here is pic

Can you tell? - I dont think you can - and they keep the heat in a treat !!

 

[middi]

There comes a point, when replacement of windows is requied on SOME older buildings, when the beast is more appropriate and nearly as beatifull as the beauty.

If you tell planning that you are replacing windows they will, most likely, insist that you use DG anyway.

 

[Taff in Glaws]

I had to replace one of my windows that was rotten to the core despite the fashionable discourse that suggests this doesn't occur (9 out of 10 joiners concurred that it was beyond repair the 10th suggested uvpc). I found a local joiner to make the window and it looks the same outside as my neighbour's original with leaded lights as well. It has double glazed units, yes the glazing bars are slightly thicker than the original but the room is less draughty, warmer and it's not uvpc. I haven't got the complication of listing and relieved I don't have to resort to secondary glazing in this particular room. Lastly it didn't cost a fortune either.

I agree with Penners you can still maintain the character of the property and use double glazing in some instances.

 

[MdB]

I agree with Penners you can still maintain the character of the property and use double glazing in some instances.

Do you have a picture? and do you mind me asking the price? Ta.

 

[Penners]

I had to replace one of my windows that was rotten to the core despite the fashionable discourse that suggests this doesn't occur

I'm not sure where you got that "fashionable discourse" from. Of course wood can rot to its core, if badly neglected over a considerable period of time.

What many of us on this forum try to suggest is that a bit of rot in a window frame doesn't necessarily imply automatic renewal of the whole frame.

 

[Feltwell]

II agree with Penners you can still maintain the character of the property and use double glazing in some instances.

I third that. I have a casement window in a dormer on the back roof of my house, both opening sections were beyond practical repair and, on replacing the roof, we found that the lower half of the frame was bad as well - the original Victorian builder had fitted it in such a way that water could pool on the lead flashing and soak into the cill....... Which had rotted, and the rot had spread to the sides of the frame. Being fair it had taken over 100 years to get to that point.

As the window frame is structural (it supports the dormer roof) and we had the roof off anyway, it made sense to replace it all then.

The new window is DG and the middle glazing bar is slightly thicker than the old but not by enough to make any noticeable difference. The window is roughly 3' high by about 2'6" across and cost me just over £300 from memory, including the glass. The frame is very heavy though.

If you like I'll post up a picture comparing it to the neighbour's original window.

 

[skier-hughes]

If you tell planning that you are replacing windows they will, most likely, insist that you use DG anyway.

You need building control consent and they will insist on DG. Our house, not listed, but the CO wanted us to use single glazing and lost in his fight with the BCO, so we have DG.

Graham

 

[Flyfisher]

Might be worth talking to Richard Smith at Old Manor Cottages in Hitchen, Herts. Email: oldmanorco@aol.com

He designs DG windows to current part L regs with 18mm glazing bars and they are manufactured under licence by Scotts of Thrapston (http://www.scottsofthrapston.co.uk/doors_construction/windowsrange.asp). While not relevant in this case, he claims to have had the windows approved for listed buildings.

I have no connection with them but I've seen their brochure.

 

[Penners]

I think Biff also makes DG window frames, doesn't he? He's a member of this forum, so you can PM him.

 

[Nemesis]

Just out of interest - has anyone any figures for just how much difference dg makes in tiny windows? Not a lot I think, when sg windows fit well. Lot of sales hype of course.

Stick on bars - look better, but when the dg units fail the whole lot has to be replaced, not just the individual unit.

 

[Taff in Glaws]

Hi Mdb, Can't access my photobucket account for pics at present (lost password with my keys!) but will try and post piccy later. I paid £350 for window approx 1300mm x 1500mm with six small dg units set into it and leaded lights in two of the top units. The glazing can be replaced if needs be without upsetting the frame or ditching the whole window.

 

[MdB]

Thanks. We have a lot of plastic windows at the moment and would love to replace them but cost is an issue and there isn't anything actually wrong with them (apart from them being plastic). £350 is cheaper than I thought they cost so it is something to think about.

 

[Penners]

I can understand your dilemma, MdB. Plastic windows are highly undesirable in so many ways (that we've all discussed fully on this forum), but once they're in, it's difficult to justify their removal.

The environmental damage of their manufacture has already been done, and to rip out windows that are still perfectly serviceable, for replacement with new ones (of any material), is only adding to your carbon footprint and subtracting from your bank balance.

It's a difficult circle to square, and meanwhile you're left looking at those awful plastic things.

 

[OLDCOLLIER]

A lot of good points made here, but it does all come down to personal choice. All of my work is on old(er) buildings, mainly involving the replacement of windows of all types, and I've done all the styles mentioned earlier, including what the upvc trade calls "astrical" bars (presumably originating from "astragel", which originally referred to any fine, though usually curved glazing bar). These are moulded glazing bars literally stuck onto both faces of the double glazed unit and affixed with double-sided tape, the double glazed unit having a spacer bar fitted internally which gives the immediate impression of a full depth glazing bar. From the pavement on the opposite side of the road most people would not know them from a 'proper' glazing bar. They're about 13-15 mm wide. To use individual units in a window with small panes looks, frankly, ridiculous, the glazing bar has to allow for the cover over the separator bar (15mm) on each unit (= 30mm) and with the rebate width on the wooden glazing bar itself of, say, 4mm, you have a glazing bar of 34mm width. Whoever makes the windows will need to find a unit manufacturer who will be happy/capable of producing units to a fairly close tolerance of 2mm all round to get a sightline that doesn't show the unit's true nature! But even after all that they still look c**p. So, 'astrical' bars can work, but be prepared to pay a premium (they also look better in oak because it takes a finer moulding) because it's more work to get them to look as if they were always meant to be there, rather than just stuck on as an afterthought. To improve the look even further, consider using gas filled units, which means you can take the unit down to 14mm (4-6-4) with the same u-value as a 24mm standard unit, and get a window that looks even less "double-glazed". If your building was either listed or in a conservation area the CO can over-rule Building Control on the grounds of retaining historical character.

 

[OLDCOLLIER]

What I didn't say in my previous posting was that a couple of years ago my local authority had a grant scheme that was run in partnership with English Heritage and applied to listed buildings and conservation areas. It was the Heritage Regeneration Scheme (HERS) which paid 50% towards repairs and a massive 70% for the restoration of original features. The job I did involved the replacement of 13 upvc double glazed windows with wooden sliding sashes and cost £11,500, towards which the customer got 70% grant aid. It was done under the auspices of the conservation department, the windows were 24 mm double glazed and used Mighton spiral balances. So miracles do happen.