Thanks for the reply - that's my thought. No structural strength to plasterboard. However, all the videos I've watched they are using 3x2 then facing with OSB and plasterboard. That would make the up[stand 95mm ish wide. mine seems quite strong, but I guess the weight of the glass and the...
The korniche guide says to have the upstand 69mm wide. I have built mine with 44mm PSE frames filled with 25mm kingspan and 18mm OSB internally bracing them. It is externally lined with 11mm OSB - it is 55mm wide, which fits the korniche lantern eaves rails exactly (with the 6mm overhang).
I'd...