1. Prepared By: Alka Shah Civil Engineering Department

2. Why Damp Proofing is required?

3. Defects caused by Dampness
Causes efflorescence which may ultimately result in disintegration of bricks, stones, tiles etc.
Result in softening & crumbling of plaster
Results in bleaching & flaking of paint with formation of colored patches
Results in warping, buckling & rotting of timber
Corrosion of metals
Deterioration of electrical fittings
Promote the growth of termites
Breeds mosquitoes & creates unhealthy living conditions

4. Damp proofing and Water proofing (IS: 4911)
Building should be dry or free from moisture in the walls
Dampness is presence of moisture
Treatment to roof: Water proofing
Treatment to floor & basement: Damp proofing

5. Causes of Dampness Absorption of moisture by building materials
Faulty design, bad workmanship or use of defective materials
Crack or inhomogeneous joints at foundation, plinth, walls, Chajja, floors or roof.
Leakages in wet areas of building like kitchen, bathroom etc.
Inadequate slope at flat roof/terrace or improper rainwater pipe connection and defective junction between roof slab & parapet
Penetration of rain water through unprotected tops of walls, parapets, compound walls etc.
Condensation of atmospheric moisture and its deposition on walls, ceiling & floors

8. Outside damaged pointing and damaged interior

9. Leakage from Ceiling
Damaged interiors

12. DPC (IS:3067)
Brick masonry below GL absorb moisture from adjacent ground
Moisture travels up by capillary action and can make the wall damp for considerable height
To prevent this, a continuous layer of an impervious material is provided, known as the Damp Proof course
All building must be provided with DPC at plinth level
Composition of DPC:50mm thick cement concrete 1:2:4 with water proofing compound(IS:2645)
DPC must be extended for full width of wall and continuous for entire length of the building, no joints
DPC does not carried across doorways, verandah, arches and similar openings

13. DPC (IS:3067) By Hot Bitumen
Application of bitumen: dried up surface of the cement concrete DPC is properly cleaned with brushes and finally with piece of cloth soaked in kerosene oil before application of hot bitumen.
Bitumen of penetration 80/100 should be heated to 160°.
Hot bitumen is applied in two coats at rate of 1.7kg/cm2.

14. DPC of Floors By Bitumen Felt
Areas having High water tables:
Provide DPC of flexible material like bitumen felt (Hessian based or Glass fibre based) or Plastic sheets over entire area of ground floor.

20. DPC membrane at different levels

21. DPC of Floors By Coarse sand
Dry areas having Low water tables:
75mm thick layer of coarse sand is generally spread over on prepared bed of rammed earth.
Rise of capillary water in granular soils is almost negligible.
75-100mm thick layer of lean concrete (1:3:6 or 1:4:8 mix).

22. DPC for UG tank or in the basement

23. To control dampness following are Treatments to External walls:
Walls get damp due to porosity of bricks and mortar joints
Treatment like plastering, pointing etc. help to prevent dampness
Non water proof cladding such as stone tiles with open joints should not be constructed so that they do not form pool of water against external wall
Projections like Chajja, balconies and porches should be constructed so that they do not form pool of water against external wall
Painting surface with waterproof cement paint or acrylic paint

24. DPC Material
DPC container with nozzle

25. DPC Material

26. Reduce Dampness by Water proofing of Flat Roofs:
Mud phuska terracing & paving with brick tiles(IS:2115)
Lime concrete terracing & paving with brick tiles(IS:3036)
Four course or six course waterproofing treatment using self finished bitumen tar felt(IS:1609)
Polymer modified bitumen polyester membrane water proofing treatment(as above)
Application of bitumen mastic for water proofing of roofs. Recommended for colder areas(IS:4365)

27. Slope in the roof :
For efficient drainage should not be less than 1 in 60
Size of rain water pipe(IS:2527): 100mm dia pipe for every 40m2 area of roof
Thermal Insulation: Provided above the terrace to save the slab from excessive dimensional change.
Material : Expanded polystyrene, polyurethane foam, foam concrete etc.

29. Water Proofing by Pressure Grouting
Forcing of cement grout ,under pressure in to cracks, voids, fissures etc. present in the parts of building
Structure is made water-penetration-resistant to check seepage of raised ground water through foundation and substructure of a building

31. Pressure Grouting

32. Water Proofing By Gunning
Deposition of rich cement mortar under pressure over exposed surface for water proofing or over pipes, cisterns etc. for resisting water pressure
Cement mortar of 1:3 shot by cement gun under pressure of 2-3kg/cm2 from the distance of 75-90cm
Desired thickness and consistency of mortar is deposited
Cured for 10days