Unlike windows made of wood to that pattern, Crittall metal windows do not deform as the structure they are built into, starts to collapse around them. Only a direct 'thump' into the glass panes will crack or break them. Over years of disuse the hinges on Crittall doors and windows tend to rust up solid or become very difficult to open - the classic give away that such a door or window has been forced open/shut, is when the panes adjacent to the hinges are either badly cracked or missing entirely. This is due to the frame upright adjacent to the hinges being deformed as the rusty hinges are forced to move. If the putty is soft or in poor condition, it is not unknown for hinge adjacent panes just to 'pop out' as the door or window starts to move.
The above recalls a hot and very dirty summer in 1962, when I spent all the vacation restoring the self same frames in a 1920 built Yorkshire farmhouse - requisitioned by the Army in '42 and returned in a parlous state in 1960. Cash was bloody tight in those days, as today I can see the Crittalls just being ripped out and replaced with UPVC! Still we must have done a good job, as apart from the addition of some secondary double glazing, most are still in situ.
