Eh,eh.. Concrete is not so "modern", and Versailles has also glass windows :-) It's not the material but how we use it !

In Avoriaz (an "old/new" ski resort) there are parts with flat roofs but then, Labro & Orzoni designed a wooden flooring, 60cm over the flat roof to keep the snow of the roof.
When freezing, the snow doesn't damage the existing waterproofness, and when temperature is rising, it allows for slow melting...
In between it allows for a big air insulation... :-)

It's always a matter of thinking right and mostly about common sense !

Happy new year everybody :-)

"What can I do, What can I write, Against the fall of Night". A.E. Housman