Double Glazing - failure after 3 years

Gengis

Hi 
we had a glass box extension built in 2021 - they fitted double panels at a cost of £12k.  They said the glass had a warranty of 10 years but did not provide me with a copy of it.  This year i have noticed condensation on the inside of all 4 panels (the walls) - the roof glass seems fine.  This suggests the glass seal has failed.  I have contacted the supplier / installer of the glass and await their reply.  i am worried in case they argue it is something i have done to make the seal fail i.e. failure to ventilate properly (which is not the case).  I think the glass should not fail within 3 years and assume they should repair or replace the panels at no cost to me.  they also quote to fit a gutter / downpipe but then told me i did not need one.  

I am right that these panels should be repaired or replaced at no cost to me?  thanks 

Keep_pedalling

Can you clarify, is the condensation on the internal surface of the pane or between the panes? The former does not mean the pane is blown.

Gengis

Yes the condensation is between the panes.  i cannot remove it either internally or externally.  It is like a fog which seems to go when the weather heats up. 

Robin9

Can you find your certificate on

Find and order your FENSA certificate

Gengis

Its an extension 4 wall and a roof panel - FENSA does not cover it.  Building inspector passed it.  

Alderbank

Lots of 'they' in your first post!

Your issue involves both the manufacturer of the sealed units and the installer. Are they one and the same?
DG units, especially large ones, are extremely sensitive to correct installation. Frames and glazing units change differently with temperature and incorrect installation leads to forces which can break the seal between panes, causing that misting, or even crack the glass.

What exactly does the guarantee say?

Gengis

The glazing firm supplied and fitted the glazing and frame.  I did not receive a copy of the warranty - I was told it was for 10 years.  I have emailed the firm requesting a copy of the warranty and waiting for them comment on the glazing mist.