Answer:
A narrow strip foundation is just one type of foundation as there are many such as the wide strip foundation and also the raft foundation. A narrow strip foundation is the most commonly used for foundation for domestic dwelling (houses) the narrow strip foundation is made up of concrete, steel, brick, block, insulation, DPC (damp proof course) and DPM (damp proof membrane). A foundation is used to keep the building erect and also to ensure that the building will not sag to one side.
A narrow strip foundation is the most noticeable foundation as this foundation that can be seen above the ground as it is not place all the way into the ground. Excavations are made so that concrete can be pored into the excavation that has been made this will be the support.