"Earnest Trawler" wrote in message ...
[...]
If this one breaks the drain then it will have to go too. A bill to fix the
drain would be annoying but not a disaster, so it is a risk I am willing to
take, the drain would go long before the roots got to the house foundations.
[...]

I'd love to hear from a structural engineer or similar authority on
this question of tree-roots and house foundations. I imagine, quite
likely wrongly, that modern concrete footings must be too tough a nut
for the roots actually to damage. But would a really vigorous root
system, in time, alter the subsoil conditions so that prolonged
passages of extreme weather (or over-extraction from the water-table)
could result in subsidence even with modern building practices?

On the other hand, old country houses in some places may hardly have
foundations at all: I had a Welsh farmhouse which seemed to be
balanced on no more than a few strategically-placed big stones on
boulder clay. It was remarkably sound; but I could easily guess at the
damage a good weeping willow might have done.

Drains are a different story, of course.

Mike.