I am extending a semi basement in a Victorian house. My extension, not as deep as the neighbour's house on one side, requires a retaining wall as I need to dig out part of the garden, approx 120cm depth. The new retaining wall I need to keep the garden back falls just over half a metre short of the neighbour's single skin brick garden wall. My party wall surveyor is making a meal of this and says I need to underpin the garden wall. Apart from all the fees he will earn I just can't see the necessity here. Am I incorrect to assume a good building can't keep the garden from collapsing half a metre away from a garden wall? hope this makes sense and I have made this clear for advice?
