Detached house is a house that stands separate from its neighbouring property on all sides, thus being physically DETACHED. When modern housing estates started to be built in the 1920's they became very popular, as were marketed being far superior to terraced houses, and had space between them and the neighbour on both sides. One side would generally have a drive. Thus they were more expensive to construct and sat on a larger plot than a semi-detached house of the same size. The adjacent properties can share a garden wall or fence, but usual practice is for the boundary on one side to be the responsibility of one party, with the neighbour on the other side responsible for the opposite side boundary.