One of the essential requirements of building is that
its interior should remain dry. A damp building is unhealthy and causes
damage to the structure. There are many causes of dampness in the
building such as due to defective design, substandard building material,
improper execution and rise of dampness from foundation. So it is most
important and necessary to provide Damp Proof course (DPC) in the
building at the time of construction.
As the foundation of all the buildings are embedded in the soil. As
bricks being porous and which are generally used in foundation below
ground level can absorb moisture from adjacent ground or soil. The
moisture travels up from one course to another by capillary action and
can make the wall damp for a considerable height. Rise in ground water
table in the rainy season may aid the entry of moisture in to the wall
and in the floor.
To prevent water absorbed from the soil rising and causing dampness
in the wall and adjacent wood work and plaster, a continuous layer of an
impervious material is provided. This layer is known as horizontal
damp-proof course (DPC). The damp-proof course should be laid at plinth
level i.e. at floor level in all building except temporary structures.
The plinth level of the building should 45cm above the ground. On the
outer walls the DPC is laid at the ground level, to save wall from
dampness of floor, vertical DPC is laid on the outer walls on internal
surface from ground to plinth level.
The thickness of horizontal DPC for boundary wall is 25mm and for
building is 40mm or 50mm. The DPC is consists of cement concrete 1;2;4
i.e. 1 is cement, 2iscoarse sand and 4 is stone aggregate or BAZRI. The
DPC should in full width of wall and should not be set back from the
face of wall for pointing. It must be continuous for the whole length of
the building. There should be no any construction joints in the
damp-proof course. The DPC is not carried across doorways and openings.
DPC laying guide line
Apply the hot bitumen in two coats uniformly at the rate of 1.7 kg
per square meter all over, so that no blank spaces are left anywhere on