Sourcing best quality sealed units?

[Alan Ambrose]

Hi,

 

We have sealed units in Crittall window frames which were installed in the '90s when the building was built. Yes, they look good but were not a great choice energy-wise. This is in a 5th floor flat which is subject to quite a lot of blustery wind. The units fail at the rate of 2-4 units a year on an continuous basis. The biggest panes are ~80x170cm and they're 4x8x4mm spec. I believe I also specified toughened on both sides.

 

Is there a way to specify higher quality units? I see in our local rag 3 companies that run continuous businesses just replacing sealed units. Can we really not source higher quality units with a much longer expected life?

 

What to people do who have triple glazed units in low u-value frames? Do you guys replace your sealed units on a regular basis?

 

Alan

[Sparrowhawk]

Hi @Alan Ambrose

 

Do you know why they're failing? Is it water being blown in between the frame and sealed unit that's reacting with the glue? Air pressure making the glass flex and breaking down the seal? Given the size I'm thinking the latter is most likely, but photos of the edges of the next one that fails would be helpful.

 

Not answering your question, but when I asked on this forum about sealed units someone gave me https://www.sealedunitsonline.co.uk/ I also found https://www.glasstops.co.uk/ which has a bigger range of glass.

[Alan Ambrose]

>>> Air pressure making the glass flex and breaking down the seal?

 

I think probably that one but I will take photos as you suggest the next time I have one out.

 

There doesn't seem to be much rhyme or reason though - I can see one which was replaced over the last few years has already failed, whereas some older ones still seem to be good. The larger units seem to have tempered on at least one side.

 

I did order some from Pilkington directly way back. Unfortunately my record-keeping isn't good enough to see which units were replaced by which supplier.

 

 

[MJNewton]

21 minutes ago, Alan Ambrose said:

I did order some from Pilkington directly way back. Unfortunately my record-keeping isn't good enough to see which units were replaced by which supplier

Might the details (or clues at least) be printed on the inside of the spacer bars?