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1. DAMP PROOF
COURSE
PRESENTED BY
AGLAIA

2. What is DPC?
• Damp proof course is used to restricts the
movement of moisture through walls and floors.
• There are mainly methods of damp proofing
1. Membrane damp proofing
2. Gunting
3. Integral damp proofing
4. Surface treatment
5. Cavity wall construction
6. Pressure grouting

3. Causes of dampness
• Rising of moisture from the ground.
• Rain travel from wall tops.
• Poor drainage, imperfect orientation,
imperfect roof slope, defective construction
etc.
• bricks suck dampness from soil underneath
and pump it to building due to capillary force.

4. Harmful Effects of dampness
• dampness reduces the strength of the
structure.
• Dampness cause falling down of plaster results
in unpleasant appearance.
• It causes insect and germ growth.

5. Properties of Materials for DPC
• It should be impervious.
• It should be strong and durable, and should be
capable of withstanding both dead as well as
live loads without damage.
• It should be dimensionally stable.
• It should be free from deliquescent salts like
sulphates, chlorides and nitrates.

6. Types of Materials for Damp Proof
Course
• Flexible Materials: Materials like bitumen felts
(which may be hessian based or fiber/glass
fiber based), plastic sheeting (polythene
sheets) etc.
• Semi-rigid Materials: Materials like mastic,
asphalt, or combination of materials or layers.
• Rigid Materials: Materials like first class bricks,
stones, slate, cement concrete etc.

7. Methods of damp proofing
1. Membrane damp proofing
2. Integral damp proofing
3. Guinting
4. Surface treatment
5. Cavity wall construction
6. Pressure grouting.

8. 1. Membrane damp proofing
• A water repellent membrane or damp proof course
is introduced in between the source of dampness
and the part of building adjacent to it.
• DPC may consist of flexible materials such as
bitumen, mastic asphalt, bituminous felts, plastic or
polythene sheets, metal sheets, cement concrete.
• It may be provided either horizontally or vertically
in floors, walls etc.
• Provision of DPC in basement is normally termed as
‘Tanking’.

9. 2. Integral damp proofing
• In this method certain water proofing
compounds are added to the concrete mix, so
that it becomes impermeable.
• The quantity of water proofing compound to
be added to cement depends upon the
manufacturer’s recommendations.
• In general 1Kg of water proofing compound is
added with one bag of cement to render
the mortar or concrete waterproof.

10. 3.Guniting
• In this an impervious layer of rich cement mortar is
deposited under pressure over the exposed surfaces
for resisting the water pressure.
• The operation is carried out by use of a machine
known as cement gun.
• The mortar mix of desired consistency and thickness
can be deposited to get an impervious layer.
• The layer should be properly cured at least for 10
days.
• Since the material is applied under pressure, it
ensures dense compaction and better adhesion of
the rich cement mortar and hence the treated
surface becomes water proof.

11. 4.Surface treatment
• In this method a layer of water repellent
substances or compounds are applied on these
surfaces through which moisture enters.
• The use of water repellent metallic soaps such as
calcium and aluminum oletes and stearates are
much effective against rain water penetration.
• it is effective only when the moisture is
superficial and is not under pressure.
• Sometimes, exposed stone or brick wall face may
be sprayed with water repellent solutions.

13. Cavity wall construction
• Cavity wall construction is an effective method
of damp prevention.
• In this method the main wall of a building is
shielded by an outer skin wall, leaving a cavity
between the two.
• The cavity prevents the moisture from
travelling from the outer to the inner wall.

15. Pressure grouting
• It consists of forcing cement grout under pressure,
into cracks, voids, fissures and so on present in the
structural components of the building, or in the
ground.
• Thus the structural components and the foundations
which are liable to moisture penetration are
consolidated and are thus made water-penetration-
resistant.
• This method is quite effective in checking the
seepage of raised ground water through foundations
and sub-structure of a building.

17. Thank you
For more…. Mail to aglaiaconnect2018@gmail.com