Replacing 'Blown' Double glazing

Cardew

This thread is prompted by a remark in a post by 'CashStrapped' in another thread:

All my neighbours have double glazing. Interestingly, after 10 -15 years of having them, everyone is gradually ripping them out and replacing them.....with new double glazing!

I have posted on this subject a few times, but many people don't realise the 'time bomb' of expenses for replacing double glazing.

I had my house built 26 years ago and aware of the problem, took independent advice and specified what was considered the best DG and hardwood frames.

After about 20 years the odd panel started to blow and over the last 5 years have spent close to £1k on replacement panels - all on the ground floor. Now I have had 4 more blow all on the first floor so more expense this summer! In addition two Velux panels in an annex have blown.

I have 6 sets of large French windows and none of those have blown; I dread to think of the cost when they do blow.

A pal of mine has had all panels in PVC frames(not installed by himself) blow in under 10 years.

Can people please give their experience of the life of panels/type of frame and approx cost to replace a panel if possible.

daveyjp

Our first one has just gone - its about 20 years old.

My parents had uPVC installed in their house in the early 1980s when it was being introduced as an alternative to aluminium.

They sold the house last year and at that point all units were fine. Some of the plastics on the slide hinges had failed, but new hinges are easy enough to fit.

saveallmymoney

Ours are from 2001, 2 panes have blown out of about 30.

I did have to replace the hinge on nearly every window last year and foam them in properly this year though. No draughts now!

matelodave

Our last home had double glazing in wooden frames for about 15 years before we moved, no problems with units blowing.

We've been in this place for nearly five years and it has UPVC frames all round. All the d/g units are marked Homestyle 6/99 so I guess they are about 15 years old and there's no evidence that they've blown (ie no condensation inside them).

If or when they deteriorate we'll probably just replace the units replaced rather than the whole window - depends on the cost at the time.

stator

You only have to replace the glazing unit, the frame doesn't need replacing. It shouldn't be that expensive.

ariba10

They do tend to go more often when in wooden frames as opposed to U P V C frames.

CashStrapped

As with everything, there are a lot of variables.

While "stator" is correct in stating that only the glazing unit should have to be replaced Some of the early double glazed windows were sealed units, which means there is no choice but wholesale replacement.

Then there is the issue of the beading (on upvc windows), which is usually individual to that old frame design. Whilst I do not think it is a problem most of the time, if you damage the beading whilst replacing the unit, it will be very difficult to source a replacment.

There is the option of re-gasing the double glazed unit. I have seen videos on youtube and may companies do offer this, however I do not know how permenant this solution is.

Then there are other things which can affect the lifetime of a dg window. The quality of the mechanisms, the UPVC frame (plastic quality) and the original installation. These are things which are very difficult to judge or know about.

I think it really comes down to how good the original company was and where/who they sourced their windows from. So a lot of luck is involved sometimes.

I had one neighbour (who moved out a long time ago) but he always did diy repairs and home rennovation to a very high standard. The UPVC DG in that house was installed in around 1992. Whilst the handles look dated now, the windows are still in perfect condition.

The thing with upvc windows is that there had been a big push to make them like "white goods". So rather than being a permenant feature of the house that you maintain, they are now like a fridge you replace every 15 years. This concept has been pushed by the companies and manufacturers.

The next marketing drive is triple glazing. The ads have recently started and it won't be long before the sales people are saying "have you got old double glazing ....."

Sorry for the long post!

CashStrapped

Cardew wrote: »

I had my house built 26 years ago and aware of the problem, took independent advice and specified what was considered the best DG and hardwood frames.

Cardew, I noticed that your issue is with timber double glazed windows. I looked into this option in detail when considering replacement of my original timber windows.

The problem with timber double glazed windows (especially those in the 80s and 90s) is that they have to be very well designed to cope with drainage.

UPVC windows can be made and designed with hidden internal channels and drainage holes to ensure water does not touch the seal around the double glazed unit. Although, as we know this is not fool proof either.

This is much harder to achieve in timber windows. Quite often the units are slotted in with a tight fit (no clearance) and puttied as per single glazed windows. This leaves no drainage channel. In addition, the oils in the putty (linseed variety I think) could also degrade the seal of the window unit. This could lead to premature failure of the seal.

You can get good quality timber double glazed units, but you have to check and ask about the drainage design.

I also found this website which goes the issues with more detail. The information seems reliable and corroborates what I have read elsewhere.

http://www.thewindowman.co.uk/misty-wood.htm

It all comes down to good design and installation as with UPVC.

Hope that helps!

Lurker21

If it's just the glass that needs replacing it should not be expensive, maybe under £100 cost per double glazed pane? Plus fitting of course. Shop around, even find a double glazed unit manufacturer to get an idea of what the fitter's materials costs are so you can see if they are ripping you off.

Smiley_Dan

Depends on the size of the pane, but 500mm by 500mm, say, locally is about £40 (not fitted).

Smiley_Dan

Personally I have never had a unit "blow" while I have lived in a house, although the house we have moved to has a number of them. The blown windows (four or five) are all softwood and the blown French Doors (one) are uPVC.