- 17 Sep 2011
- Reaction score
- Wst Sussex
But the key question is - how critical is a gap between the glass and the sash? Is this the primary reason for the failure of the sealing? I am concerned that is I clean it all up and rebuild with the same DGUs the problem will just reoccur
It is a key reason for failure, yes.
Double glazing is usually installed as a drained and vented system.
So an air gap is required all the way around and at the bottom, there should be drain holes drilled so water can escape.
If DG units are in contact with water constantly they break down.
No gaps means higher risk of premature failure.
Typically DG unit spacer bar sightline is 12mm, so a rebate of 16mm will allow a gap of 4mm
Double glazing can be fully encapsulated and that's how slimline glazing is done, but it's not recognised as optimal.
Double glazing is made by a having one sheet of glass on a bench, then spacer bar, which is about 6mm wide is laid on the glass its about 6mm in. Then the 2nd glass pane is laid on. Then hot melt glue goes in between the glass, sealing the glass and the spacer bar. Now that joint is waterproof, but if it's constantly wet and combined with temperature changes, slowly the water will work its way in.
I've seen DG units with 6" of water in the bottom!