My next house is a 1963 Brutalist (It looks like a concrete box with two ribbon windows on the first floor and one window on the second--and has fins)

But the set-back third floor has a glass wall, and the back of the first floor is a series of french doors with only piers in between, basically.

The original on the third was probably a slider with stick built mullions with glazing held in by quarter round surrounding it. Now it is vinyl replacements and a set of cobbled french doors.

There are still fixed lites with the wood frame and quarter round in the ribbon windows and in transoms over the french doors. (There are ventilating awnings in combination with the fixed). All kind of functional but ugly.

The house was designed by a well-known architect but built for a modest-budget buyer. So the ideas are there but some of the execution is not.

Anyway, I would like to replace the glass wall with something appropriate and modern (and perhaps enclose the upper end of the stair well in a matching glass box so I can do zoned HVAC--you need to have the first floor at about 60 to get any relief on the third, in summer)

Hopes are WAY too expensive, but since there is only this one large unusual wall, and then not so many other windows I was looking at Fleetwood. Any experience?