I am about to do a single storey rear extension that had planning permission refused as my neighbour contested I have now reduced the size of the extension to fall in line with the 3 metre rule and have a building notice in force. We are going to be using the existing foundations as the building inspectors are happy with them.
Does this still come under the party wall act if the exterior wall is built along the boundary but on existing foundations?
Section 6 (the part that deals with excavations within the 3 metres) would not apply if you are using existing foundations.
If you are building a new wall up to the boundary but on your own land you will need to serve a Line of Junction Notice under section 1(5) of the Act. To avoid serving notice you could keep the wall back slightly but it may be in your interest to serve notice if you will need access to your neighbour’s land to build the wall.
How far back would the wall need to be to avoid serving notice?
Keeping the wall back any distance at all will technically remove the need for a Line of Junction Notice. I think I would keep it back 2-3 inches so that it can be shown on a drawing that it is not on the line of junction. Do bear in mind the point about access in my original reply.