shit
excuse christophe, you don't stink, only I said thank you 3 times per post, it was often intended for you so I didn't think I had to say it again;)
concerning the oversteering, all the craftsmen that I saw told me that it cost as much as changing the window or the front door, moreover it is not a must either in performance apparently
The experience of this old house has shown me that when I started a room, I had to redo everything: window, elec, cracks in the ceiling, parquet flooring / glazing, etc ... So I progressed piece by piece to finish with the stairwell last fall.
welcome to the club
thanks for the link for the insulators I will read that (there is a bunch of pages already
)