Skirting board (or baseboard) covers the essential "expansion gap" that is needed between floors and walls. The reason for this is that floors (particularly wooden floors) expand and contract depending on the temperature and humidity of the room and the material. If there were no expansion gap, the floor would buckle and lift somewhere in the middle and be very time-consuming and expensive to repair. The skirting board, therefore, sits above this gap and prevents it from being seen. In retro-fitted wooden floors, this job is often taken over by scotia - which is like a mini skirting board.