Replacing glass panes with double-glazed units

Nov 22, 2007 41 Replies

I have some quite large timber-framed casement windows in the front of my house. As the frames are in serviceable condition, I had wondered about replacing the glass panes with double-glazed units, in the same frames, as a less expensive alternative to having the entire windows replaced. I think the frames are deep enough. Has anyone done this? Would I simply bed the units into the rebate, in glazing silicone or similar, put some beading over, and job done? How thick are today's standard DG units? Can one get them made to measure? Who makes them, and how much do they cost?



I've searched the archives, but couldn't find anything on this.



Regards Richard


That's basically it, yes.

You can certainly DG units made to order - that's how the whole replacement window industry operates. Thickness varies... best visit a local double-glazing fabricator where they make the stuff on-site (not one of the mationals) and talk to them. Prices aren't outlandish.

Dvaid

Almost any glazing company/glass merchant will make double glazed units in various thicknesses and any sizes.

Fit as you described

Tony

Contact a local glazier. Obviously windows break, an they wil be able to give you caper and vrese on replacement DG glass panles,.

One thing is relevant apart from depth and that is bead - the seals around DG units are quite wide ..You may end up stripping the window frames and making new rebates. Unless they are nice hardwood, it may be just as little work/cost to make new ones..

Take care. If you have hardwood you might well succeed but from bitter experience softwood frames do not seal well enough. If you ask unit makers they will advise you not to try. The units will mist up after a while even if you paint regularly. I'm now having to think about replacing all windows for this reason.

Peter Scott

Sounds to me like the DG units were too rigidly mounted - the timber frames move with the seasons so the units have to be fixed in such a way as to allow this.

Where did he say he wasn't using DG sealed units?

The glass is steaming up because of the way the glass was fitted, or it was poorly made. The units are sealed, and the only way to break that seal is to separate the glass sections slightly. Are yours too tight in the frame? They need a gap all the way round them, otherwise expansion of both the frame and glass unit may cause one side of the unit to have more pressure on it than the other, thus causing a twist in the unit, and the seal breaking down. Alan.

Yes, you can do it, though you will need deep rebates in both directions on the wood frame. You will need a 3mm gap all the way round the glass (glazers sell ready made plastic spacer blocks for this). Bed it on silicone, then another bit of silicone on the front, with, if possible some beading, though some panel pins would be enough to hold in smaller glass. The smallest depth of DG unit is 14mm where I get mine from - 4mm glass,

6mm spcer,and 4mm glass. If you have 4mm glass now, then you can see that your rebates will have to be at least 10mm deeper. Alan.

Stepped DG units only need a shallow rebate but their appearance on the inside is not to everybody's liking.

Basically not possible. DG units too thick, heavy, and have wide seals which wouldn't be covered by the rebates. Waste of money too, DG is generally not very cost effective. Plenty of cheaper alternatives e.g. heavier curtains, 2ary glazing, etc

cheers Jacob

Basically very possible. Magnet used stepped units in their wooden windows for years

. DG units too thick, heavy, and have wide seals

Basically you have no idea. It's not the DG units that are too thick, the seals on your brain failed and it misted up.

We did the whole of our house over abou five years, that way we didn't notice the cost at all. The oldest have been in place for about fifteen years and there have been no problems at all.

The rooms certainly are more comfortable. Before we had them we used secondary dg, that was nothing like as effective and it was a real pain because of dirt and insects getting between the glass panes.

We gave measurements to our local commercial glazier, the factory sealed units, made to measure, were always ready for collection next day. They were not expensive but I can't remember actual costs right now, also all our windows were different sizes. Spouse did the work, occasionally I'd help him ease a unit into position from inside if he were up a ladder.

The greatest advantage over this system is that you're not cutting down the light as happens with commercial plastic dg frames. You can do it to your own timetable and as funds are available. You have to look closely to see that they're not the original glazing. Also, you end up with several old panes to use as garden cloches :-)

I'm surprised about that - I've been banging on about it for a very long time :-)

Mary

>

DIY using a few sealed units in existing frames is a lot different, cost wise, to having someone in to do "double glazing" and can certainly be very cost effective.

MBQ

Yup, Matthew Marks posted about his experience putting DG units in his single glazed French windows in this group some time back.

Googling it up - 10 years in fact. Wonder how they held up?

Hmmm. Interesting. Looks like I might thinkagain about redoing the dg myself in existing frames. Damn. Means I've got to paint them again. Fifteen years sounds good. Can I just check. These are softwood, not hardwood frames you are using?

Peter Scott

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Oh dear. I must expect mine to fall out any day now. then. Despite having lasted for over 15 years.

Personally I like to see through windows in the daytime. Night too, often. And heavy curtains in a kitchen would be a health hazard. Secondary glazing looks cheap and nasty.

...

All the timber fabric of our house is softwood.

One or two spots in the window frames showed signs of rot when we were re-glazing them, not really surprising in a 60 year old house which wasn't well maintained for various reasons. The members were replaced with softwood, primed and painted. So far they seem to be OK.

It is now :-)

Mary

I was quite impressed with the Everest secondary glazing a neighbour had done recently. Despite their bad name, it wasn't that expensive, and is fairly unobtrusive on sliding sashes

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