- By Providing a Damp-Prof-Course (DPC)
The continuous layer of an impervious material, which is provided in between the source of dampness and part of the structure is called a Damp-Proof Course.The function of providing damp proof course is to prevent dampness and it is laid either horizontally or vertically. Horizontal D.P.C is generally laid 150 to 200 mm above the ground level on the external walls and at plinth level in case of internal walls of a building. While Vertical D.P.C is provided to connect the horizontal D.P.C in the external walls with the floor level to check the flow of moisture from the underside of a floor into the walls.
- By Surface Treatment
This method consists in painting the exposed surface of the wall with a water repellant paint. Material to be used for painting the wall surface must be durable and effective to check the absorption of moisture by the wall.
- By Integral Water-Proof Construction
This method consists of adding certain compound in the mortar or concrete to make it more dense by filling the pores through chemical action or mechanical effect. If 5% sunlight soap is added in the water to be used for preparing the mortar, the pores get clogged and a coating of water repellant substance sticks to the wall surface which makes it sufficiently Damp-Proof.
- By Special Devices
Dampness can be prevented by using some special devices which are given below:
- By constructing the external walls of sufficient thickness.
- By using the bricks of good quality for constructing the external walls.
- By building the walls in rich cement mortar.
- By providing string courses and cornices.
- By fixing the down water pipes in sufficient number so that water may not leak through the junction of wall and the roof.