cracks in double glazed units

a crack has spontaneously developed in a double glazed window. it's in the inner panel and all the way through. the workmen actually saw it happening!

more seriously, cracks have also developed in a double glazed unit consisting of toughened and laminated glass which is on the roof. this crack has migrated around the perimeter and across the unit and another has begun to meet it.

both the window and the unit were put in place by trained craftsmen, who have installed similar on other houses. these are in place now, 3-4 months. cracks developed recently. no problems with units in the other houses (so far).

both firms are refusing to talk to me about compensation or even replacement. the window, being smallish, is not such a worry but the roof unit is.

house is not yet lived in,so these units have not experienced much thermal differential.

is this spontaneous cracking a known problem with double glazing, and what can i do to get these firms to behave honourably?

Very unusual to be totally honest with you. I am working with double glazing for aprox 20yrs and have never heard of it happen 'all by itself'.

Yes, naturally a double glazed unit can crack when we are pinning it into place if a pin hits Timber Windows and Doors) off it but thankfully this would be few and far between or if the double glazed unit was cracked at the edge the crack could travel across but very rare to come across this, but it would be a single crack.

I have 13 velux windows in my house which are aprox 12 years since they were fitted and they have laminated to the outside like you have in your post and they are all still perfect, my parents have 3 for the last 30 yrs aprox and the windows themselves could do with a hand but the double glazing is perfect.

thanks nhg.
yes,i too have the impression that it's unusual.the window was put in as a unit by lads trained by rationel and 3-4 months later they came in to do some work and saw this crack happening.
the roof unit was laid on a plinth by the same lads and all was well for 3-4 months again but then one day i spotted these cracks. no one had been on the roof for some time.

wouid you say that it was possibly a fault in the manufacturing?

Are there any signs of settlement of the surrounding structure? Any issues with window openings getting more difficult to open close?

I've heard of this happening before where a building settling put such pressure on the windows that cracks occured. In fact, I heard it here.
Leo

Like Leo, I'd be looking for settlement/subsidence too.

One of the glass panes in our garage door cracked a couple of years ago and the subsequent investigations revealed a cracked drain running alongside the garage.

The same thing keep happening to bedroom windows in an apartment In own , crack always stars around the same place & travels right across the inner pane, this is the 3rd time since 2006 it has been replaced

feileacan said:

a crack has spontaneously developed in a double glazed window. it's in the inner panel and all the way through. the workmen actually saw it happening!

more seriously, cracks have also developed in a double glazed unit consisting of toughened and laminated glass which is on the roof. this crack has migrated around the perimeter and across the unit and another has begun to meet it.

both the window and the unit were put in place by trained craftsmen, who have installed similar on other houses. these are in place now, 3-4 months. cracks developed recently. no problems with units in the other houses (so far).

both firms are refusing to talk to me about compensation or even replacement. the window, being smallish, is not such a worry but the roof unit is.

house is not yet lived in,so these units have not experienced much thermal differential.

is this spontaneous cracking a known problem with double glazing, and what can i do to get these firms to behave honourably?

Click to expand...

Hi feileacan,

As Leo has implied in his post, you may be looking at the wrong firms.
The double-glazed units themselves tend to be very strong and dimensionally stable and I would be very surprised if the defect originated with them.

The crack may originate in either -I have seen a double glazed unit crack only once, relatively recently.
A glazed conservatory appeared to be moving away from the gable to which the frame was attached.
It wasn't possible to be definitive on my inspection since there were no movement gauges attached and the movement crack was not huge.

This past winter seems to have caused problems for structures and substructures, many of which only seem to be manifesting in the past few months.
That is to say, there were no immediate defects after the freeze, but they seem to have come with the rise in ground temperatures after the deep frost we had.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

Fairly common complaint, caused by settlement. Replace windows with smaller ones ( a couple of mm). Bank up the "cavity" behind the glass with silicone and apply gaskets as per norm.

Hopefully settlement will sort it self out.

None of my buildings have settlement cracks or cracked double glazing units in them (touch wood).

Its not a common complaint in buildings which have the benefit of an architect and an engineer carrying out site inspections.

Its a sign that the ground was not properly inspected/prepared and/or that the foundations were not correctly prepared/designed/built.

As I've posted here before, building is not for amateurs and you get what you pay for - "hopefully settlement will sort itself out" is not the right attitude.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

thanks all.

the large double glazed unit is laid flat on a raised ledge like a lid on a jar. this is on the roof and there is no evidence of settlement or detachment. the roof is flat and the unit is not enclosed.

the glass firm is a manufacturer and does not install - he is claiming that his product has no guarantee and claims the cracking may have occurred due to the interplay of shadows and the 'strong sunshine'! i find this incredible.

site was seen to by engineer and house designed by architect who often uses circular glass panels in roofs in his designs. no problems with any of those so far and some are up to 10yrs in.

what do ye think?

Why was this product chosen/specified if it does not come with a guarantee?

But guarantee or not, you still have your standard consumer rights.

naivety! i assumed there would be a guarantee of at least 1yr.also they gave the cheapest estimate.

Your architect should have advised you on the choice of supplier and the lack of guarantee.
You ALWAYS seek a guarantee, and I would not go down the bits and pieces route for something on a roof.
There should be a quilt of guarantees leading seamlessly from one item to another - i.e. the rooflight to the weathering surface to the gutters to ensure there is always someone to call on.

With the way this has been done, it sounds like the gauge of the glass/strength was too light for the intended use and it may have been damaged in installation.
Mind you, flat glazing on a roof has to be one of the dodgiest design details ever invented.

I've seen such glazing installed apparent ill effects, but its down to materials and sealing gaskets, not good first principles detailing.
I would be surprised not to see them all fail over time as the sealing materials fail due to weathering action.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

feileacan said:

the glass firm is a manufacturer and does not install - he is claiming that his product has no guarantee and claims the cracking may have occurred due to the interplay of shadows and the 'strong sunshine'! i find this incredible.

Click to expand...

Window cracked by sunshine - must have been designed for the Irish market then.

thanks complainer - that's what i thought too!!!!

onq,
manufacturer has been on to pilkingtons which is where he got the glass. he is sticking to his sunshine theory, but pilkingtons suggest that the laminate may have been too thin at 6mm. they suggest both panes be toughened. manufacturer still unwilling to replace at his cost. i suggested that if pilkingtons say two toughened panes that i would pay the extra for that ,but i'm not at all sure that manufacturer will bear the rest of the cost.


architect had minimal input other than design. i found the supplier/manufacturer and it was they who specified the type and thickness of the panes after my explaining to them what was wanted and the dimensions of the opening. the unit was sealed with windscreen adhesive.

am very worried now as to wisdom of this feature. we are in conamara where weathering will be significant - almost constant salt winds due to our being on the sea.

latest on cracks!
sunshine theory has been more or less dumped, though first glass maintain that sun and shade can crack double glazed units mentioning a school whose windows crack frequently due to the children putting posters on the glass. incredible that teachers would allow that to happen a second time let alone several times!!
rang pilkingtons who supplied the glass. they suggest weight of unit is the cause or the laminate was too thin. other suggestion is that the seal on the unit may have broken down (in 4 months?) due to weathering. failing all that then the design is wrong, such a unit is not fit for purpose.
so, on to the architect, mike rice. naturally, he defends his design. not only does he routinely design in such units but he himself has 3 of them on flat areas in his own house. i've seen one of them in situ and it's as large as mine if not larger.
basically, i've still got a cracked unit and no joy from either pilkingtons nor first glass.
any further ideas, please?

cracks in double glazing

latest on the cracks!

pilkingtons now say the glass is fine and able to take the wind and snow out here in conamara. they're no longer saying that it should not be used horizontally.

they now think that the glass may not have been adequately supported as it was being lifted into position and that it flexed, causing the outer lite of the laminate to vent and thus the cracks over time.

is this likely and if so where does it leave me in terms of repair and guarantee under statutory rights?