A damp proof course in a building is intended to provide a barrier to the passage of water from the exterior of the building to the interior, from the ground to the structure or from one part of the structure to another (BS 5628-3-2005).
Water or moisture is the prime cause of deterioration in building materials and constructions encouraging the growth of mould which in turn is harmful to health.
Building Regulations require that buildings are designed to be stable, and to ensure that water neither penetrates to the interior nor damages the building fabric.
Ground water can penetrate the building fabric from below, rising vertically by capillary action.
Rain, snow and hail is under a slight head of pressure and under the influence of wind action can travel obliquely, horizontally and even vertically upwards.
The function of a DPC is to prevent moisture or water passing from one part of the building to another.
Damp proof courses should be designed in conjunction with flashings and damp proof membranes to ensure a continuous barrier.
A DPC can also be used to form a cavity tray which is designed to capture water within the cavity wall and drain it to the outside of the building via weep holes in the external skin.
The inclusion of a DPC can affect the overall stability of a structure so careful consideration must be given to the correct selection of DPC for installation within different masonry constructions and building types.