SLIM DOUBLE-GLAZING CONCERNS of FENESTRATION PROFESSIONALS...
"The depth [depth of edge-seal] is important. In the various ultra-slim units the sealant depth is being reduced from 'about' 12mm to 'about' 6mm. The reason they're doing this is to allow installation of these mini-units in 11-12mm rebates traditionally designed for single glasses. Rebate depths of 18mm minimum are provided for 'standard' double glazed IG units. The width [i.e. 12mm v 20mm v 24mm thickness] has little to do with this [PR]."
"Real traditional glazing bars cannot be glazed with standard IG units (the glasses are too big), and should not be glazed with ultra-thin units, for the same set of reasons as before.[ PR]"
... SO when those slim units fail prematurely & your supplier fails to respond: thats when you need to call Philip Rougier..!!
We should make the clear distinction between actual sealant depth and sightline depth, which are two very different things. Some of these 'slims' have as little as 1-2mm of sealant behind the spacer product - do the maths (and that's assuming perfect application of spacer and sealant every single time). Totally inadequate by a country mile and against sealant manfuacturers minimum depth requirements, and also the minimum sealant depth requirements of the manfuacturers of dessicated foam spacers that are widely used.
Q3. Method of glazing: definitely an issue as they [slim double-glazing co's] all seem to show solid bedding rather than Drained & Vented. But that isn't an inherent fault of the unit, only the way it is installed?
Agreed. So we have units with inherently weak seals that are now being installed badly as well.[PR]