Double glazing with obscured glass

[JohnW2]

I'm contemplating installing a double glazed panel to replace the current single-glazed obscure glass pane (downstairs loo). I've done a lot of reading (here and elsewhere) but have got rather confused by the fact that there are actually two questions, but answers nearly always talk as if there was inly one, making it rather difficult to know what is being said.

I'm talking about the situation in which one of the panes of the DG is just 'standard (not obscure) plain glass and the other is 'obscure', with patterning/whatever on just one side. The two questions are therefore (1) which of those two panes goes on the 'outdoors side' of the DG unit and which goes on the 'indoors side' of the unit, and (2) as regards the obscure pane, which way should its patterned side face? I've found this 20-year-old post here which seems to answer those two questions separately and clearly ...

The patterned side should face the inside of the DG unit, and the patterned glass should be on the inside of the building. I assume this is so the pattern doesn't attract dirt, and to make the glass easier to clean by facing a flat glass face to the outside (the patterned glass may have slight indentations on the unpatterned side).

.... so, that is seemingly saying that the plain (not obscured) glass goes on the 'outdoors side' of the unit, and the obscured glass on the 'indoors side', and the latter should have its smooth side facing unto the building (and the patterned side facing the inside of the unit - all of which seems to make sense. If that was correct when written, does it still reflect what is regarded as the 'correct' (at least, 'best') approach today?

Thanks for your insights!
Kind Regards, John

 

[crank39]

There are 2 things at play here you are right

1/ When I first started out in 1990 patterend units were always fitted with the pattern facing the room, clear side outside, never had a definitive answer as to why, some say the smooth surface was better for the window cleaners squeegee, others said it was to do with if the unit was leaded then the lead wouldn't stick very well to a rough surface(lead strip only being applied to the outer pane

2/ With the advent on Low E coated glass being part of the regs, April 2002 i think (Pilkington K or Saint Gobain's Planitherm) this coating could only be sprayed/applied to the smooth clear glass and had to facing the room so from that point in time patterned units where fitted the other way around ie patterned glass outside, clear glass inside

3/ A single pane of patterned glass has a rough textured side and a semi smooth side, when sealed into a unit the rough textured side faced into the cavity of the unit, if fitting it as a single pane then the roughest textured side would face the room, the semi smooth would be outside

Hope that helps

 

[JohnW2]

Hope that helps

Well, sort-of - but, given that there are the 'two questions', I'm not totally sure of your meaning of "inside" and "outside"! On the basis of the 2008 post I quoted, what I was contemplating was per this diagram, with the faces of the two panes of glass labelled A, B, C & D (A, B & D being smooth, with just C 'patterned').

However, you now say ....

2/ With the advent on Low E coated glass being part of the regs, April 2002 ...... from that point in time patterned units where fitted the other way around ie patterned glass outside, clear glass inside

Given that we are well past 2002, does that mean that what I've illustrated above would not today be regarded as the 'correct' (or, at least, best') aproach ??

 

[crank39]

Inside means indoor and outside means outdoor but i thought that might be self explanatory! Cavity means just that, inside the cavity!

Your diagram shows the make up of the unit pre April 2002, post 2002 just swap outside and inside labels but the Low E coating stays on surface B but I think you're overthinking it slightly because when the glass shop make the unit for you they will seal it to industry spec with the rough patterned side C facing inside the cavity so it kinda makes your whole post academic really

 

[JohnW2]

Inside means indoor and outside means outdoor but i thought that might be self explanatory! Cavity means just that, inside the cavity!

Well, it certainly would be clear and self-explanatory IF people used that third word ("cavity") as well as the other two, However, that word has not appeared in most of what I've read, with many people seemingly using "inside" to refer to both 'inside the building'# and 'inside the cavity' - hence the potential ambiguity that has been somewhat confusing me

Your diagram shows the make up of the unit pre April 2002, post 2002 just swap outside and inside labels but the Low E coating stays on surface B but I think you're overthinking it slightly because when the glass shop make the unit for you they will seal it to industry spec with the rough patterned side C facing inside the cavity so it kinda makes your whole post academic really

Yes, it occurred to me after I posted my message that my question could be at least partially academic for the reason you give. However, I would still presumably be left with one question, namely 'which way around' to install the entire unit which had been made up for me (although that might perhaps be addressed by 'labelling' on the unit?). If I did as you say and simply reversed the outside and inside labels on my diagram, I would then obviously have the patterned glass on the 'outside' (with its patterned side facing into the cavity) - is that what I should do?

Thanks for your assistance, and patience

 

[crank39]

Assuming you are going to order a thermally efficient unit with low e glass and warm edge spacer it will say on the glass sticker, 'this side facing exterior/interior' or similar, if you're not then it won't and you can fit the unit whichever way around you like