follow on youtube for video lecture Damp proof course method cause effects

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

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

8. • 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. • 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. • 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. • 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 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. • 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.

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