How long should a sealed double glazed unit last?

[Nigel Watts]

Just over five years ago I had a roughly five foot square double glazed unit fitted into the bay of my modern rear extension, to replace the previous one which cracked after about four years (the upper window in the photo below). The seal on the new window seems to have failed and there is now a considerable amount of condensation inside. The windows are in a bespoke steel frame, which seems very rigid, and held in place with mastic.

The last time I had the window replaced it cost me about £600. Have I just been unluckly or could there be something more fundamental? Do I have a case against the previous supplier (I don't remember there being any guarantee)?

 

[middi]

If double glazed units are well made , ie- high quality sealants used to bond the double glass units, these should last a lifetime.
--BUT !!!, even if the DG are well made they are still subject to sealing compounds, mastics, solvents, corrosive chemicals, paints, oils and general sealing quality used to bed the DG units in their respective casements as these can have adverse reaction with the actual DG seal and can lead to premature failure.
difficult to say why, in your case, the DG units have failed.

Middi

 

[worms]

My understanding was that the bigger the unit, the greater the difference in expansion of the two pieces of glass and therefore the greater the risk of the seals failing, especially if the window is south facing (as yours appears to be). I guess the metal frame could add to expansion/contraction issues, but I'm not sure you need to go that far to get a reason for failure of the seals (the cracked unit is perhaps another matter - but is that not more likely to be contraction of the frame in very cold weather?)

However, I thought most units came with a 10 year guarantee? Perhaps they don't do that with the bigger bespoke ones?

 

[billybuntus]

I'd personally have that frame split into two sections rather than shelling out every 5 years for a new unit.

 

[vicky whitworth]

If big DG units are known to be more likely to fail how do all those places on Grand Designs manage when they have acres of glass? And why is it that people on Grand Designs want to live in a goldfish bowl anyway? How weird is that? :?

 

[Lime]

If big DG units are known to be more likely to fail how do all those places on Grand Designs manage when they have acres of glass? And why is it that people on Grand Designs want to live in a goldfish bowl anyway? How weird is that? :?

I completely agree with the goldfish bowl comment.
It puzzles me too.
That puzzlement extends to modern cars too... so much glass it is unpleasant.

...re the double glazing problem, how long does it last.
I asked EXACTLY that question of the glazier putting our extension windows in and his reply was possibly 10 years, maybe more, maybe less, it all depends on how much water gets into them!
(I made a mental note not to allow too much condensation to form on them.)

 

[88v8]

In our cottage, there are and will be no DG units while I own the house... but in our previous house I had units made to fit our south-facing wooden sashes, they had a 1" air gap and were still good after 30 years. They were bedded in glazing tape internally, and Arbo 1081 externally.

On the other hand, I also had our (wooden) conservatory double-glazed; the air gap was only ½" and some units were very small - perhaps 1.5sqft - while some on the roof were 20sqft. Most of them large and small failed within ten years. They were unbedded internally and externally, just wooden bead. By then, I had come to dislike anything float glass, so I intended to replace those in the windows with single-glazed lead lights, but we moved house instead.

In your case, could be the mastic has attacked the glue, or just poor original manufacture. If you replace it, get a guarantee, and get a written spec from the makers for a suitable bedding mastic. Arbo will have something suitable.
http://www.arbo.co.uk/
The units should be located in the frame by plastic spacers to take up thermal movement. Which makes me think that you should also get some recommendations from the maker as regards installers.... I dare say there are bodgers in that field, as in all aspects of the building trade.

Ivor

 

[AMc]

Some mastics attack the seals as others have noted, if they've been installed with the wrong stuff then they'll fail faster.
When I discussed my failed older units with the glaziers supplying the new ones they told me that any reputable manufacturer would expect at least 10 years if they'd been fitted correctly. He also showed me that "most" units have the manufacturer printed on the spacer bars - my failed old ones being the exception to his surprise!. My first point of call would be the supplier/installer to discuss the problem.

 

[LadyArowana]

If big DG units are known to be more likely to fail how do all those places on Grand Designs manage when they have acres of glass? And why is it that people on Grand Designs want to live in a goldfish bowl anyway? How weird is that? :?

A lot depends where the property is, if you have enough land around, or you are in a high rise then it can be OK. We are currently in an almost 30 storey that has acres of glass right across the living area and floor to ceiling of one wall of the bedrooms, but we are a low floor and the trees are now at our level. Makes it surprisingly private.I went through a squirrel feeding phase but they made a horrible mess of the balcony and then decided that it might be interesting to come and see where the food was coming from, inside squirrels wasn't on my agend, so I decided they should go back to foraging. All the windows are double glazed in metal frames, not sure where they were sourced from. I'm sure they expand as the temperature heats up during the day, but no issues so far, touch wood.

 

[Flyfisher]

A lot depends where the property is, if you have enough land around, or you are in a high rise then it can be OK. We are currently in an almost 30 storey that has acres of glass right across the living area and floor to ceiling of one wall of the bedrooms, but we are a low floor and the trees are now at our level. Makes it surprisingly private.

Do you have parking problems though? If so, perhaps this would be useful.
http://www.bbc.co.uk/news/world-asia-19360613

 

[LadyArowana]

A lot depends where the property is, if you have enough land around, or you are in a high rise then it can be OK. We are currently in an almost 30 storey that has acres of glass right across the living area and floor to ceiling of one wall of the bedrooms, but we are a low floor and the trees are now at our level. Makes it surprisingly private.

Do you have parking problems though? If so, perhaps this would be useful.
http://www.bbc.co.uk/news/world-asia-19360613

No we get 2 spaces on the Basement 1 level and 3 rd and subsequent cars can be parked on Basement 2. Not a problem for us with only 1 rather old Toyota Camry. More applicable to whichever apartment has the Rolls Royce and 2 Lamborginis that the man came to clean and rung our doorbell by mistake. It's almost Formula 1 time and so all the boys remember they have their sexy cars under the wraps and start trundling up and down Orchard Road. It's all very silly as Singapore is so tiny there's nowhere to go, can't even sensibly go across the causeway to Malaysia as you will likely be walking home.

 

[Flyfisher]

Given the high prices of car permits (do they still have the rationing and monthly auction system there?) and the space available in Singapore, it's a wonder that anyone bothers with cars at all. Just goes to show how strong our love affair with the car really is!

 

[LadyArowana]

Given the high prices of car permits (do they still have the rationing and monthly auction system there?) and the space available in Singapore, it's a wonder that anyone bothers with cars at all. Just goes to show how strong our love affair with the car really is!

Yes to buy a car you have to get a COE ( certificate of entitlement ) which is done on a price/ quota basis depending on the sort of car. I believe you also have to prove that you have a legal parking place for it. They have cheaper ones that only allow you to drive on weekends or public holidays, if you want to take one of thos cars out other times you buy a coupon for the day. They come with red number plates, easy way to identify the classic Sunday driver.

 

[Feltwell]

They come with red number plates, easy way to identify the classic Sunday driver.

What, even easier than looking for a brown Triumph Dolomite automatic driven by a man wearing a trilby? :wink:

OK - bit behind the times I admit.

 

[Fred Drift]

They come with red number plates, easy way to identify the classic Sunday driver.

What, even easier than looking for a brown Triumph Dolomite automatic driven by a man wearing a trilby? :wink:

OK - bit behind the times I admit.

Talking of the price of fish, just where is Penners? :wink:

Fred.

 

[LadyArowana]

They come with red number plates, easy way to identify the classic Sunday driver.

What, even easier than looking for a brown Triumph Dolomite automatic driven by a man wearing a trilby? :wink:

OK - bit behind the times I admit.

Talking of the price of fish, just where is Penners? :wink:

Fred.

I'm also wondering where he's got to, there were a couple of comments in another thread that I felt sure would tempt him to the keyboard. I do hope he isn't incapacitated by his bad back, he's a martyr to it you know.

 

[FamilyWiggs]

I had a message a couple of weeks ago saying he was rather busy....but surely the fact that we are so busy is why we spend so much time on here? :roll:

 

[worms]

Well he last visited on Wed 5th Sep at 3.38. Perhaps off on some exotic travel?

 

[LadyArowana]

Well he last visited on Wed 5th Sep at 3.38. Perhaps off on some exotic travel?

Shhhhhhhh, that's brunch time here and we were hoping to keep things secret :lol:

 

[worms]

Shhhhhhhh, that's brunch time here and we were hoping to keep things secret

I never found the tropical version of Kit Kats were quite right, somehow...