Welcome to Goy. I cannot giveyou definitive advice but I looked at the link below and have copied the info on roots for you. I would take advice as it is not a problem I would have anticipated. http://www.wisteria.it/informa-e.htm The roots: The wisteria roots spread so strongly and abundantly that if planted near walls or pavements they can easily grow into them causing serious damage . To prevent this from happening it is advised, whilst planting, to insert a corrugated plastic panel which will force the roots to take other directions, as they are unable to pass through it. Place the plastic panel (at least 2m long) 80cm deep, between the plant and the wall or pavement (or the surface to be protected). In the case of walls and pavements made with cement this problem does not exist.
The following link also mentions Wisteria as a real problem.
http://www.dailymail.co.uk/tvshowbiz/article-562290/Nigel-Kennedy-costly-outbreak-mass-wisteria.html Hope this is of use.

Poor you its difficult when neighbours are thoughtless? Your household insurance or CAB may be able to give you advice on how to proceed?

When you see how many are growing happily against buildings it is hard to think that they can be so troublesome. I hope you have sympathetic neighbours. A word with them first giving details of what you have found out might be enough to make them think again.

I think its the flat roof that might be worrying them SG.

I thought it was the drains and foundations Reita was concerned about and the fact that it is a new build. The fact that the building has a flat roof could also be a problem, I wasn't thinking about it getting up and then having nowhere to go. I am still shocked at the problem the roots can offer considering that having a wisteria climbing your house walls is the epitomy of Englishness. Wisteria can certainly climb up at least 2 or 3 storeys.

Its only 12" from her flat roof extension it may just be that she does not want it on her house - I wouldnt want it to grow over my flay roof if I had one. Perhaps we will never know SG?

We can only hope her neighbours are sympathetic.

:))