DAMP PROOFING

Damp proofing at ground level is the provision of a barrier across the whole width and length of a wall, which cuts off the capillary supply of moisture naturally rising from the ground. In external walls, to avoid rain water splashing up above the damp proof course, the DPC (damp proof course) has to be positioned at least 6 inches (150mm) above the outside ground.

TECHNIQUES

  • Use of damp proof courses
  • Water proof or damp proof treatments
  • Integral damp proofing treatment
  • Cavity walls or hallow walls
  • Guniting or shot concrete or shotcrete
  • Pressure grouting or cementation

USE OF DAMP-PROOF COURSES

These are layers or membranes of water repellent materials such as bituminous felts, mastic asphalt, plastic sheets, cement concrete, mortar, metal sheets, stones etc. which are interposed in the building structure at all locations wherever water entry is anticipated or suspected. The best location or position of D.P.C. in the case of building without basement lies at plinth level or structures without any plinth level, it should be laid at least 15cm above ground level. The damp proof course is provided horizontally and vertically in floors, walls etc.

Damp Proofing
Damp ProofingDamp Proofing
Damp Proofing
Damp ProofingDamp Proofing

WATER PROOF SURFACE TREATMENTS

The surface treatment consists in filing up the pores of the material exposed to moisture by providing a thin film of water repellent material over the surface (internal / external). External treatment is effective in preventing dampness.
Many surface treatments, like pointing, plastering, painting, distempering etc. are given to the exposed surfaces and also to the internal surface.

WATER PROOF SURFACE TREATMENTS
WATER PROOF SURFACE TREATMENTSWATER PROOF SURFACE TREATMENTS

INTEGRAL DAMP-PROOFING TREATMENTS

The integral treatment consists of adding certain compounds to the concrete or mortar during the process of mixing, which when used in construction acts as barriers to moisture penetration under different principles.

INTEGRAL DAMP-PROOFING TREATMENTS
INTEGRAL DAMP-PROOFING TREATMENTSINTEGRAL DAMP-PROOFING TREATMENTS

CAVITY WALLS OR HALLOW WALLS

A cavity wall consists of two parallel walls or leaves or skins of masonry separated by a continuous air space or cavity. The provision of continuous cavity in the wall per effectively prevent the transmission or percolation of dampness from outer walls or leaf to inner wall or leaf. The following are the advantages of cavity wall.
As there is no contact between outer and inner walls of cavity wall, possibility of moisture penetration is reduced to a minimum.

CAVITY WALLS OR HALLOW WALLS
CAVITY WALLS OR HALLOW WALLSCAVITY WALLS OR HALLOW WALLS

GUNITING

The technique of guniting consists in forming an imperious layer of rich cement mortar (1:3) or fine aggregate mix for water proofing over the exposed concrete surface or over the pipes, cisterns etc. for resisting the water pressure. By this technique, an impervious layer of high compressive strength (600 to 700 kg/cm2) is obtained and hence this is also very useful for reconditioning or repairing old concrete works.

PRESSURE GROUTING OR (CEMENTATION)

The mixture of cement, sand and water under pressure into the cracks, voids or fissures present in the structural component or the ground. In general, the foundations are given this treatment to avoid the moisture penetration. This technique also used for repairing structures, consolidating ground to improve bearing capacity, forming water cut-offs to prevent seepage etc.