Secondary Glazing

[ireneadler101]

Hi all,

We have some rather ugly (but helpfully, effective) secondary glazing on our sash and bay windows.

We would, in due course, like to replace this with something a bit loss obtrusive. I've come across this company - CosyGlazing http://www.cosyhomecompany.co.uk/cosy_glazing.html - and wondered if anyone else had used them?

I got a quote to do one very small sash and was told it would be £1100 + VAT, which seems a lot! It's not clear whether this includes sash refurbishment or not.

In theory, this just looks like thermal plexiglass with a magnetic strip around the edge. If I were to try and fabricate it myself, I'm sure it would be considerably cheaper. What I can't work out, though, is how they get the plexiglass to fit on the top sash, allowing the bottom sash to slide up with it still on. Anyone tried to do this themselves?

 

[malcolm]

Secondary glazing has struck me as very ugly and very expensive. I need to add some to my lovely slim Edwardian windows to make building regs happy. I visited Duration in Essex who seemed the cheapest for the DIY happy, but still ugly.

My sash windows at the rear are easy. A new double glazed sash is £1000 to £1500 and my existing windows are cheap and nasty replacements. You might not want to refurbish your sash windows if you fit secondary glazing - the ventilation is useful to reduce misting.

I hit upon the idea of having some wooden mouldings made to secondary glaze the windows I want to keep. I have still not fully figured out the plan, but have been prompted by the guy who will make them to figure out how they will work. Some testing and design is planned over the next few months. Glass, magnetic tape mounting, upper and lower wooden mouldings to retain the glass (slide up then drop into place), then mouldings at the sides fixed by magnetic tape.

 

[Flyfisher]

It's a dilemma isn't it? I'm also not keen on the look of secondary glazing and some prices can be more expensive than a brand new window . . . which sparked an idea in my mind.

We have a very old, probably original, oak window with quite crude metal casements and leaded glass. Unfortunately, the flint/rubble wall above had collapsed onto it and the lack of a decent lintel put the entire frame under considerable strain, causing the whole window to bow outwards and one of the mullions to partially break at a joint. This abuse has also moved the metal casements such that they no longer close properly and there are gaps of about a finger's width in places. The good news is that the wall has been rebuilt and a substantial lintel installed, but although the weight has been lifted from the frame it shows no sign of moving back from its current bent and damaged state. It's on the border of end-of-life, though could possibly be repaired with a great deal of TLC and the application of joinery skills beyond my abilities - which would likely mean a large price tag, and even then it would still be a cold and draughty window.

So I'm considering secondary glazing, but not in the sense of adding some sheets of glass to the existing window - I'm thinking of a secondary window frame. The wall are thick and a completely new frame could be fitted in front of the existing window without disturbing it at all yet still provide a decent internal window sill. I've not yet decided on the design of the new internal window, except it would be wood (of course) and might even be double glazed itself.

I'm still in two minds about the idea. It would likely be cheaper (or at least no more expensive) than a 'traditional' secondary glazing system, but would allow the existing original window to remain in place and untouched while providing an effective thermal solution. Plus, it would be completely reversible and require no loss of original fabric.

There's no great rush to decide as the room concerned is only being used for storage at present, but time is creeping ever closer to when something will need to be done as part of making the room habitable again.

 

[88v8]

Double casements are a common feature in quality period homes in Germany, and perhaps elsewhere.

And I did the same thing in our library, although that was for noise suppression. The inner casement was double glazed.

Ivor

 

[Roger H]

I need to add some to my lovely slim Edwardian windows to make building regs happy.

Hi Malcolm,

Out of interest, why has building control got any leverage on your windows?

 

[malcolm]

Hi Malcolm,

Out of interest, why has building control got any leverage on your windows?

I'm doing a change of use from a pub to a house so fall under Part L1b. It's not too damaging - the windows at the rear are 1990s cheap replacements and I refused to change the original front windows, hence the secondary glazing.

 

[Flyfisher]

Double casements are a common feature in quality period homes in Germany, and perhaps elsewhere.

And I did the same thing in our library, although that was for noise suppression. The inner casement was double glazed.

Interesting. I didnt know that - and there was me thinking I was being innovative. :lol:

 

[Roger H]

I'm doing a change of use from a pub to a house so fall under Part L1b.

Ah yes. And not listed. Fair enough.

 

[malcolm]

Ah yes. And not listed. Fair enough.

It is interesting that you can still flatly refuse to do some of the things building regs want. Even without listed protection I have a very good relationship with my conservation officer who can help with these things on a beuroctatic level should I run into trouble. I am in a conservation area thankfully.

I just tell building regs the conservation officer is like a dog with a bone and ask if they can help find another solution. That has worked by itself so far.

 

[Bogart]

Been myself looking at improving the glazing on our grade II gaff. Most as rightly pointed out looks appalling. Considering getting some double glazed units made up putting a magnetic strip around unit and existing window frame and bingo triple glazing I can live with the look for a few months of the year and when spring returns take them off until the next winter

 

[livias]

Magnetic strip secondary glazing is great but I am not convinced that the magnets would take the weight of a double glazed panel

 

[MikeG]

Double casements are a common feature in quality period homes in Germany, and perhaps elsewhere.

And I did the same thing in our library, although that was for noise suppression. The inner casement was double glazed.

Interesting. I didnt know that - and there was me thinking I was being innovative. :lol:

Erm, no. I've designed a number of fixed and inward-opening inner windows in Listed buildings over the years. The trick is to watch your sight-lines. The last thing you want with nice slim-line original windows is a nasty heavy-framed window showing behind it. Keep the framing of the inner window back to at least the line of the outer.

 

[88v8]

On the right the extension we had built on our previous house.
The downstairs was triple glazed with secondary casements.



Here, a corner of the window from within



And here



And here, as left by the builders.



But that was a purpose-made double casement, and was primarily designed for noise suppression with a 4" gap between the panes.
There was some sort of seal around the inner casements, a sort of fabric let into the frames. The outer casement was not ventilated, but in the few months we actually used the room before selling the house, it never steamed up. However, that house was not damp. Whether it would work as well in our present house, is another matter.

Ivor

 

[MikeG]

......... The outer casement was not ventilated, but in the few months we actually used the room before selling the house, it never steamed up. However, that house was not damp. Whether it would work as well in our present house, is another matter.

Ivor

I always specify a few holes downwards through the cill to the outside to allow some ventilation. The single glazing only acts as shelter for the double glazing, and so some airflow in there is unimportant in terms of heat loss.

 

[88v8]

The inner casements were dg, the outer were real leaded lights and therefore single glazed.

Oddly enough, never had trouble with interstitial misting.
At the front (faced N) the sitting room had 1960s secondary glazing, that stuff with the sheets of glass in plastic surround, and the clips.
In the bedrooms I installed my own secondary, with dg units in brass frames.

In neither case was there any exterior ventilation.
But the house was pretty dry.
Nearly every room had an open fireplace. We had gas ch. Rh never exceeded 45%. Indeed, with the ch we had to watch that the humidity didn't get too low.
So, in my ignorance, I got away with the absence of venting.

In our present cottage my secondary dg is copiously vented to the exterior but some of it mists so badly it almost might as well not be there. The difference is that in this room as I write, the rh is around 68%.

Ivor

 

[Flyfisher]

Thanks for those photos Ivor, it's the sort of thing I was thinking about. Using large panes means allows the outside window features to be clearly visible, though I think I'd try for slightly narrower frames. Ventilation wouldn't be a problem for the window I'm thinking about as the original outside window (also real leaded SG) already has quite large gaps around its metal casements

 

[parkview094]

Although not commenting at the time, this thread about double glazing prompted me to do some research.

Our bathroom is always cold and whilst the single glazing in the window doesn't help, the main culprit appears to be the icy cold draught blowing in around the openers. We researched replacing the window vs. getting it refurbished, but we couldn't find anyone willing to do anything for less than £1200.

The rest of the windows in the house are in generally very good condition, but are all single glazed and some of the larger rooms are chilly now winter is setting in.

So, spurred on by this forum, I came across these guys https://www.secondarydiyglazing.com/ and thought for the money, I'd give secondary glazing a go.
Despite ordering in November, I've finally got around to fitting the first window today..



I opted for the 'sliding' system for the bathroom so we could get at the openers behind. Everything is a very snug fit with the included draft excluders. Probably not helped by the fact I spec'd 4mm plexiglass rather than 3, they're not the easiest things to slide, but overall I have to say, I'm reasonably impressed. The proof will be in the bathroom temperature tomorrow, but for £100 all in, it seems like a neat solution even if it only lasts until we save up enough for more substantial window work.

I've also ordered one of their magnetic kits for our lounge. Will post my thoughts once that's been installed.