THIS IS NOT A GOOD IDEA!!
Pretty? Yes, but still not a good idea.....
One of our large wisterias is in full second bloom of the season,
and is threatening to drown my laundry room!
Hate to think how much weight there is on the roof ... oh dear !
I love the second flowering on a wisteria, more subtle than the first flowering that appears before any leaves, but even I have to admit that this baby is getting out of hand - it has ideas above it's station and will have to gently, or not so gently, be brought back under control ... Sigh ...
The only place I have seen a whole building covered by a wisteria is at the entrance to the famous National Trust garden of Hidcote (below) in the UK. The year the roof needed repairs, they found a company willing to suspend the wisteria by crane, re-tile beneath the wisteria hanging in mid air then gently relower. Needless to say the National Trust and I do not enjoy the same budget !