Footings can cross the boundary if the neighbour serves a notice under the
Party Wall Act. You can't object.

Anything above ground can not without express permission.

dg


"BillR" wrote in message
...
Mike Taylor wrote:
Your neighbour can build as close to the boundary as the local
authority permits except none of their construction can extend onto
or over the boundary on your side
I am mystified that you say that the proposed extension roof will
finish "under" your eaves. Do your eaves and gutter extend over the
boundary? If not then nor can theirs. If you belive yours do you may
not have the correct boundary line.
The same goes for the foundations. They should in theory be
approximately 150mm (6") wider than the wall. So in theory without
eaves/gutter etc you should not be able to have a wall closer than
150mm to the boundary unless building control and planners agree. If
eaves and gutter is brought in to the equation then it would be
further back than that

Indeed, a friend of mine was having an extension built to which the
neighbour had not objected.
However, when the footings were being dug he pointed out that they were
encroaching on his side and that the finished building's eves and gutters
would be over his side.
This resulted in the footings having to be moved some 300mm at
considerable
cost and delay.