I have been given planning permission to build a first floor extension on top of an existing flat roofed single story part of my house. The house is detached, however the existing wall which is part of my kitchen extends up to and runs along the boundary line between me and my neighbour. On the other side of the boundary is his drive and garage. He submitted objections to the council but planning permission was still granted. In order not to upset him further I have changed the plans so that guttering does not overhang on my neighbours side. As this is an exising wall and so no change to the existing foundations are required and we will not be overhanging at all do I still need to give notice to my neighbour that we are starting building work and can he stop us doing so?
Section 1 of the Party wall Act is only invoked when an owner is building a new wall on the line of junction. As the boundary to which you refer has already been built on you can increase the height of the wall without serving notice.