I live in a house with a basement kitchen that extends under only part
of the house. This includes the rear addition and an area in the main
house under the staircase (to provide a stairwell for the basement).
The parts of the house that do not currently have a basement have a
huge sub-floor void almost as deep at the basement (2m+). The
difference being made up of loose rubble etc. It seems that the
foundations are at the same level thoughout the house (I guess this
has to be the case?). I would like to extend the basement further
under the house to provide a second bathroom. What are the gotchas if
any? Do I need planning permission? Building control? How should I
proceed? Any help would be gratefully received.