Here now let us see what is Damp Proof Course (DPC) in civil engineering construction and how Damp Proof course is generally use to protect against Dampness. Dampness generally happens due to water which rises up through soil due to capillary action or also due to Water seepage in high humid areas.
What happens when there is no Damp proof course(DPC)
- The plastering on the wall comes off.
- Surfaces of walls are with white patches. This is called efflorescence.
- Due to this dampness in any room fungus or bacteria may form which is allergic to some people and also Possible damage to wiring in the walls may occur which may lead to short circuit and also exposure of rebar in a long run.
- Some times we can see some vegetation or small plants coming through slab and walls.
Types of Damp Proof course applications
The various areas in structures where Damp proof course (DPC) is applied in civil engineering.
For Underground tanks with Porous soils
Here, for the whole area below the tank we will have to provide damp proof membrane. Specification for the same can be “Polyethylene sheet of mass 1kg/sqm can be provided below the base slab of tank”
For walls of building coming in contact with soil
Polymer based cementitious coating is provided upto min 150mm above ground level.
Above Plinth / Plinth masonary
Suitable cement mortar with available water proofing compound can be applied of approx 12 mm thick and bitumen coating 85/25 grade can also be applied over this surface below the brickwall.
A rubber strip type runs all along the wall to prevent the moisture of water to come up by capillary action.
Damp Proof Course for Roof
Various codes for application of Damp proof course (DPC)
- Bitumen felts for water proofing and damp-proofing – IS 1322 : 1993
- Waterproofing of Roofs with Bitumen Felts – IS 1346 -1991
- Bitumen primer for Damp proofing – IS 3384 1986
- Code of practice for design and installation of damp-proof courses in masonry construction – BS 8215:1991