DIY double glazing for metal windows (old listed building)

[cliffski]

Hi all, new poster here...

I have a nightmare house to insulate, because it's a) very old(1750) and b)listed, which has proven a nightmare. Anyway, the current topic of stress is the windows which are the original metal framed single-pane old (bumpy) glass, set into big old stone window frames. (each window has 3 separate sections, with metal frames folding a bunch of small glass panes.

Traditional metal secondary glazing has been ruled out by a higher authority, but we are assuming there is a lot of heat loss through them, so are seeking a solution.

I've been looking at this DIY magnetic double glazing, where you buy some adhesive magnetic strips, stick one lot to the metal frames (or wood, for some of the newer windows) and the other to a cut-tosize bit of polycarbonate, then just stick them together for the winter.

a) does it work?
b) does the polycarbonate thickness matter? it seems you can go 4mm to 12mm
c) because of openers, I can only do 2 out of the 3 panes in any one window. Surely this is is still worth doing because something is better than nothing?

Thanks in advance

also... What is it about this forum that it makes firefox run at 43% CPU. what the hell is it doing?

[guydewdney]

I have a 1722 water mill - although not listed, I too, have a 'higher authority' that cooks, cleans has ruled out standard secondary glazing.

We have very deep window recesses, nearly 2 feet thick walls - and a current plan is to have nice hardwood double glazing windows, single pane per hole (as much as possible) opening 'inwards', but set close to the old windows, which are to be left very very slightly ajar.

the old widnows keep out the rain, leaves, birds, but allows condensation out. The new windows keep the heat in.

Are the windows part of the listing? Nice hardwood replacements can look very nice, if you arnt precious about the iron windows (which is unusual / unlikely to be original original 1750 - more likely a later addition?)

[brackwell]

Dont building regs say when replacing a window it has to be done to the latest spec?  I am sure that this bridge has already been crossed and that certain construction/styles have been "approved" for such old buildings. A local glazier was telling me of special construction double glazing developed for listed places.   The iron windows cannot be the original but of course the style might be.  Is this grade 1 or 2

Ken

[BruceB]

If a building is listed, then the whole thing is listed and potentially anything you want to do within the curtilige of the building is subject to listed building consent.

Theoretically if you replace windows they would have to meet the latest building regs, but as soon as you start delving you will find that in order to protect the historic environment the conservation officer trumps the building control officer and energy efficiency goes out the window.  About the only exception where I have seen a building control officer stand up to a conservation officer is on fire issues.

There have been very thin double glazing sections designed to fit in critall windows if those are what you have.  Some conservation officers are willing to allow them.

We have a listed old mill and when doing a refurbishment of the industrial part, were allowed to replace the metal windows with hardwood double glazed ones in a sympathetic style as there was a real mish mash of broken windows.

There are 2 approaches:
- quietly do what you want and hope non-one notices, but that can be unwise with listed buildings because anauthorised alterations are in principle a criminal offience;
- have an informal chat to your conservation officer on the local council to see what the art of the possible is.

The one good thing about listed building consent applications compared to planning or building regs applications is that around here (South Glos) they are free.

Regards
Bruce

[djh]

"also... What is it about this forum that it makes firefox run at 43% CPU. what the hell is it doing"

I see essentially no CPU load using a couple of different versions of Firefox, so there must be something specific to your system.

[Dyslexicbloke]

We live in a static caravan, rented, so permanent secondry glazing or new windows just arn't an option.
We tried some of that plastic film that you apply with double sided tape and then shrink with a hair drier to get it taught and clear.

We were amazed how much difference it made and how durable it was .....

You would need some extra depth but I suspect you cpuld arrange that with UPVC trim strip or small section planed timber.

The best thing would be that it is all tempererry and attached with tape or pads, I doubt that it would constitute an infringement of the protection status of the building.

A compromise I know but might be worth an experiment, especillay as it would be very cheep to try.

A;l

[cliffski]

we are only grade II listed, thankfully!
We had considered fitting large wooden-frame secondary glazing (replacing the windows is a no-no, because we adore the look of them), that could be removed in summer, but the problem is that the frame required would be quite large, and block out quite a chunk of the window. What we want (and what i guess everyone in my position wants) is some magic super-solution that lets me plonk a piece of super-glass or plastic over the individual panes, which just conducts heat less. One day...

I think given the relatively cheap cost of it, I might give the acrylic sheet + magnetic tape thing a try, to see what difference it makes. The only problem is that the openers on some windows stick out too far to make this an option..
When are scientists going to produce some magical transparent 'paint-on' aerogel that is cheaper than water? *tsk*.

(also seems it *was* my machine, it's fine now)

[Katy]

I had similar problems with our Victorian school. We kept the sashes as they were original & rather lovely but finally bit the bullet & replaced some with fixed triple glazing, drastic but the house was unliveable & fortunately not Listed. It got me to thinking though, as I'd experimented with roller blinds & velcro some time ago. I came up with an idea to make thermal roman blinds (with Thinsulate & two layers of Mylar) which seal to the sashframe using magnets & now I'm making them! Not sure of the protocol on here for advertising as I've only just spotted the forum. They've been specified on five of the 'Retrofit for the Future' refurbs & now I'm getting data back from two which are being monitored (using reed switches linked to the magnets). Let me know if you want more info.

(My MacBook using Firefox doesn't like surfing today either, I think it might be something to do with flash)