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old windows: has anyone retrofitted slimline double glazing?

(20 Posts)
totallyrandom Wed 19-Sep-12 21:55:44

I live in a late Victorian/early Edwardian house with arts&crafts influences. We have lots of draughty original casement windows, some very tall beautiful windows with Edwardian panes/others more dull simple landing type casements. I also need to replace a few windows/casements.
After lots of online research, I have decided to try and stick with the original windows where possible and to "refurbish" them. Now I need to decide whether to go for secondary glazing or to have slimline double glazing retrofitted coupled with draught proofing. Has anyone faced similar decisions and what did you go for and why? If you got slimline double glazing, does it work to reduce noise (part of our house fronts a road with traffic) as well as being thermally efficient? Are you happy with it?
Regarding replacement of windows, what wood did you go for? All the joiners I have spoken too want to use kiln dried exotic hardwoods which worries me a bit. I think I would prefer something more local like Scottish Douglas Fir as it has worked in our climate for ages. Thanks for responding if you have faced any of the above decisions...

suburbandweller Thu 20-Sep-12 09:24:08

I have just done exactly that - had existing single glazed casements (1912 Edwardian house) refurbished, draft proofed and retrofitted with super slim double glazing. It was expensive (more so than having the windows replaced with new timber double glazing - we had a number of quotes) but we were very keen to keep as much of the original windows as we could and felt this would be the most sympathetic way to improve what was already there. I was also concerned about any new window fitters destroying the internal woodwork, as some of our windows have beautiful (original) wooden surrounds.

I did ponder secondary glazing but have never seen any which looks good - it always seems so intrusive. I was also concerned that it wouldn't work on my windows given the internal woodwork and lack of straight lines iyswim.

I cannot recommend highly enough the people who did our windows here. They were true craftsmen and did a beautiful job - our neighbour is an architect and even he has been impressed with how difficult it is to tell that the windows have been refitted. The insulation has immediately improved - draughts are gone and DS' room, which is south facing, didn't get nearly so hot on summer days as it did before we had the work done. There's also a definite difference in noise levels. I am very pleased we decided to refurbish (sorry for the essay, can you tell how happy I am with my windows?!)

Sausagedog27 Thu 20-Sep-12 13:47:23

Secondary glazing will be better for the noise. It's always better to retain what you have got however-sadly modern woods are not the same quality as the older woods. It is possible with slimline glazing however it's expensive. You could look at getting windows fully draftstripped which can make a big difference in itself. Good luck with whatever you decide!

PigletJohn Thu 20-Sep-12 18:24:09

secondary glazing will be more effective for sound and heat. Some people have net curtains, which makes seconday glazing invisible.

It is not so convenient for windows that you often open, although vertical sliding sashes are good, if you can get them.

If any of your casements have rotted and need to be replaced, then you might as well have sealed units in them, with the rebate made to measure. Make sure they are very thoroughly treated with preserver, sealed and painted, because they will not last 100 years like your old ones.

totallyrandom Tue 25-Sep-12 17:03:51

Thanks everyone for the helpful responses!!

thereonthestair Tue 25-Sep-12 17:07:15

I have 1902 house, retrofitted slimline doubleglazing, and am actually thinking of replacing it in part with sceondary glazing, because it really doesn't do what it said on the tin. It has helped keep some noise out and heat in, but really very little.

PigletJohn Wed 26-Sep-12 01:04:27

Sorry to hear that. Is it draught-stripped?

The EDPM P and E sections are quite good (the foam is rubbish) but I prefer the furry "brush" or "velvet pile"

You may have to order it as it comes in different sizes but a good window company should know.

Are yours the old casements or new?

It is true that a bigger gap is more effective, especially for noise, and secondary glazing is much better for draughts.

totallyrandom Wed 26-Sep-12 11:08:03

If we are doing secondary glazing, should we still draught proof the original windows? There seem to be 2 schools of thought on this. One says it is good to have some ventilation (through original draughty windows) to stop the secondary glazing steaming up. Some other companies say on their websites that it better to draught proof original windows too. I am confused!

I need some replacement windows too (will go for wooden double glazed ones). From my research online, one option is to get really good quality softwood (Douglas Fir or British Columbian Pine) and just use stain on it which looks almost like paint (called Sadolins Supadec) in that way the wood breathes but is protected apparently. Also, apparently one then just needs to clean windows and apply more stain in the future rather than paint and the stain does not flake. Anyone used this before?

PigletJohn Wed 26-Sep-12 13:55:09

If the new, secondary glazing is well draughtproofed, then there should be no airflow from ill-fitting original windows into the room. Any slight leakage between the gap and the outside world will indeed prevent condensation on the glass (some people incorrectly think that warm air from the house will prevent condensation, but warm air always hold more moisture than cold air)

If the old windows are very gappy, or the wind blows in noticably, then I would tend to fill in the big gaps. It is not unusual for old window frames (and badly fitted plastic replacements) to have big gaps between the frame and the brickwork. These can best be filled in using Expanding Foam, which comes in cans like shaving foam, with a plastic tube to inject it into the gap, and sets rigid. It expands more than you think, and is very sticky and messy in use, so you need to protect clothes, skin, carpets, hair, eyeballs, window frames and walls from drips and bulges, which are very difficult to clean off except by waiting for it to go hard and then scraping. Have a large box of disposable gloves handy. Clingfilm can be taped to the wall and windowframe to protect it during application, and you must have dustsheets on the floor. Buy a can of Foam Eater for cleaning up when you buy the foam. Once you get the hang of it, it's wonderful. Once set, it can be trimmed with knife, and painted or coated with silicone sealant or decoreating filler.

PigletJohn Wed 26-Sep-12 14:07:27


I have had Sadolin, and don't much like it. It obscures the grain of the wood, and goes dull, and is very expensive. However it does seem to be true that you can clean it, samd lightly, and apply a new coat fairly easily. I'm not convinced that it is very hard-wearing, but my neighbour still uses it on his front door and balcony, and it seems to work for him. He uses a dark brown stain.

Varnish and most transparent stains are a lot more trouble.

itllallbefine Tue 22-Dec-15 12:29:35


I recently asked a local joiner to look at the Georgian sash windows in our flat. We're looking for noise and draught reduction, unfortunately I am very reluctant to use secondary glazing since this will incur the further cost of buying blinds and curtains for the windows (the shutters will not close if we get secondary). I also don't like the look of it.

The joiner proposed draught proofing as first port of call and possibly reglazing with acoustic glass - which would be single glazed.

He said that in his opinion slim line DG was not worth it if the original windows were in decent nick (which he thought they were).

Is he wrong - would slim line DG be better for noise and draught reduction. According to the websites that make the stuff it would it very expensive ? Does slim line DG slot into the existing wooden windows ?

Any help/advice appreciated.

bchakrab Fri 14-Oct-16 15:50:08

Hi, has anyone had slimlite panels installed in their windows. We are planning to do the same and I would be interested in some feedback from you about how these panels are faring yrs down the line? Internet discussions talk about early break down in the installations and early problems with condensation.
Would be most grateful for feedback. Thanks

ireneadler101 Wed 04-Jan-17 12:16:11

I'd also be interested to hear if anyone has had any issues with slimlite double glazing as we are on the verge of having this installed in our sash windows.

JillyTheDependableBoot Wed 04-Jan-17 12:49:00

We recently had our sash windows refurbished and decided against double glazing. The window guy advised that draughtproofing would make the biggest difference in terms of heat retention, and that as we're on a quiet road noise reduction wasn't a priority. Also, we leave our windows open a lot of the time anyway. The new windows look great and have made a massive difference in terms of how warm the house is.

LaJustice Tue 14-Feb-17 17:47:24

Would advise not to use slimlite although I guess you may have better experience. We spent 1.5 years trying to get one of their official agents who is also an installer to instal the windows. Lack of professionalism. Lack of care. No paperwork. No CE markings. Awful people, awful experience. Save your money

parking2017 Wed 15-Feb-17 09:02:14

I work at a carpenters/joiners and slimline double glazing is not something I would recommend.

They fail quicker, so not a good long term option unless you dont mind reglazing your windows.

DevonMumof4 Sat 13-May-17 11:29:06

We had slimlite double glazing put in quite a few of our windows 7 years ago. Almost all of them have now failed and just look cloudy. Would definitely NOT recommend.

scissormister Mon 15-May-17 10:29:16

Interesting thread. Not sure if I can help but we have just bought an Edwardian house with secondary glazing (From the 70s?? Not recent) and while it is obtrusive and awkward, I can't really see a better doesn't feel cold or draughty.
Have friends who have awful problems after fitting new windows in an old house so not ever going to do that.

Mikelittle Thu 14-Sep-17 15:06:52

Re Slimlite Glass in Edinburgh -DO NOT DEAL WITH THIS COMPANY!!!!!!! - we have had severe problems with the windows clouding and they have refused to even discuss the matter with us. I spoke to Jim Hickman at Slimlite and he was abusive and dismissive towards me. Lots of other customers appear to have had the same problem and have had no help from Slimlite to resolve. Stay away from these people!!!!!

Mikelittle Thu 14-Sep-17 15:07:24

Re Slimlite Glass in Edinburgh -DO NOT DEAL WITH THIS COMPANY!!!!!!! - we have had severe problems with the windows clouding and they have refused to even discuss the matter with us. I spoke to Jim Hickman at Slimlite and he was abusive and dismissive towards me. Lots of other customers appear to have had the same problem and have had no help from Slimlite to resolve. Stay away from these people!!!!!

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