WATERPROOFING and DPC in structure and building

Presented By:
Asst. Prof. Dhwani Bhavsar
BCM- V
DAMP
PROOFING
&
WATER
PROOFING

“Dampness is moisture in the air, or on the surface of something.”
WHAT IS DAMPNESS…?

SOURCES
 Capillary Action of Ground Water
 Splashing rain water which rebounds after hitting the
wall surface may also cause dampness.
 Penetration of rain water through unprotected tops of
walls, parapet, compound walls, etc. may cause
dampness.
 Sloped roofs, rain water may percolate through
defective roof covering.
 Ground Water Table – if it is high, will affect the
foundation
 If the building is located in the area which cannot be
easily drained off.
 The newly constructed walls remain damp for a short
period.
CAPILLARY ACTION

SOURCES
dampness.
foundation
easily drained off.
period.
RAIN WATER PENETRATION

SOURCES
dampness.
foundation
easily drained off.
period.
Moisture entrapped during Construction

SOURCES
 Level of the site: low lying areas cannot be easily
drained off and thus causes dampness in the structure
 Climatic condition : condensation of the moisture
present in the atmosphere under very cold climate.
 Orientation of the building : the walls subjected to
get direct showers of rain or getting less direct sun
rays.
 Defective materials: like porous bricks, soft stones,
etc. especially when used in external walls.
 Improper Plumbing Conditions
Orientation of the building

SOURCES
rays.
Low Quality or Defective Construction

SOURCES
Improper Plumbing Conditions
rays.

EFFECTS
 Unsightly patches on walls and ceilings.
 Softening of plaster and crumbles.
 Woodworks decays due to dry out.
 Electrical fittings are damaged.
 Cause rusting and corrosion of metal fittings.
 Floor coverings are damaged.
 Dampness leads to breeding of mosquitoes, growth of termites and germs carrying diseases such
as tuberculosis, it also aggravates asthma.

EFFECTS

It is a type of moisture control applied to building walls and floors to prevent moisture
from passing into the interior spaces.
WHAT IS DAMP PROOFING…?
 It is a common problem in
buildings.
 It refers to access and penetration
of moisture content into building
through walls, floors, roofs etc.
 It is important to take measure to
prevent dampness.
 These damp proof courses may be
provide horizontally or vertically
in floors, walls etc
Basically D.P.C is provided to prevent the water rising from the
sub soil and getting into the different part of the buildings.

 The best location for D.P.C in case of buildings without basement lies at the plinth level or
in case of structure without plinth should be laid at least 15 cm above the ground.
WHAT IS DAMP PROOFING…?

DIFFERENCE BETWEEN DAMP PROOFING & WATER
PROOFING
 DAMP PROOFING :
Treatment to a surface to resist the passage of water in areas like foundations,
exterior walls, metal surfaces, metal staircases, etc.
 WATER PROOFING :
Protection to prevent water entering in the internal & external building structures like
toilets, swimming pools, water tanks, retaining walls, roofs, etc.

PROOFING
DAMP PROOFING WATER PROOFING
 Is tar based  Is rubber based
 Slows the process of water absorption.  Prevents the process of water
absorption.
 Is initially more expensive.  Is cheaper in the beginning, but leads to
more expensive problems later on.
 Cracks along with the foundation cracks.  Water proofing stretches to cover those
cracks.
 Does not resist water well enough to
prevent oversaturation from ground
water.
 Prevents from ground water & from
rains.

PROOFING

WHAT IS WATER PROOFING…?
 Building water-proofing is a process
which is designed to prevent water from
penetrating a building.
 Usually extensive waterproofing
measures are added to a building at the
time of construction, to provide moisture
control from the start.
 Waterproofing may also be done after a
building is built, to address problems as
they emerge or as part of a building
retrofit.

TREATMENT FOR PREVENTING
DAMPNESS
1. TREATMENT OF FOUNDATION
2. TREATMENT OF BASEMENT
3. TREATMENT OF FLOORS
4. TREATMENT OF WALLS
TREATMENT FOR PREVENTING
WATERPROOFING
1. WC
2. BATHROOMS
3. TERRACE
4. ROOFS & CHAJJAS
5. BASEMENT, SWIMMING POOLS,
UNDERGROUND DUCTS
6. UNDER GROUND & OVERHEAD
WATER TANKS
APPLICATION

MATERIALS
1. Bitumen
 Material :
Black viscous mixture of
hydrocarbons obtained naturally or as a
residue from petroleum distillation.
 Application :
3mm layer of bitumen is applied over bedding
of concrete or mortar.
It is applied with brush in hot condition.

MATERIALS
2. Bituminous or Asphaltic felt
 Material :
Rolled flexible material made of bitumen used
in parapet walls, roof, etc.
 Application :
It is provided with an overlap distance of
100mm on sides. These laps are then sealed
with bitumen.
Application of asphaltic felt on roof.

MATERIALS
3. Mastic Asphalt
 Material :
Composed of suitably graded limestone
aggregates bound together with asphalt
cement.
 Application :
It is carefully spread when hot by means of a
hand float

MATERIALS
4. Bricks
 Material :
Bricks with water absorption of less than 5%
are used for this purpose.
 Application :
2-5 courses of such bricks are laid with
cement mortar.
2 courses of bricks with water absorption of
less than 5%

MATERIALS
5. Stones
 Material :
Granite, trap and slates are used
 Application :
These stones are used to full width of wall.
Stone laid as damp proof course to the full
width of wall

MATERIALS
6. Mortar
 Material :
Cement mortar with 1:3 ratio and ample
amount of lime and waterproofing agents is
used
 Application :
It is laid in foundation, ground slab, parapet
wall, plaster, external wall

MATERIALS
7. Concrete
 Material :
Rich concrete mix with ratio 1: 1.5 : 3 or 1: 2: 4
with thickness of 75mm to 100mm
 Application :
Concrete painted with two coats of hot
bitumen is used as horizontal D.P.C.
Cement mortar with waterproofing agents
used in wall

MATERIALS
8. Metal sheets
 Material :
Copper, aluminum, lead are used for
construction joints.
 Application :
Sheets of metal should be coated with asphalt
and laid in full thickness of wall.
Bituminous seal must be provided for this type
of waterproofing. Metal sheet provided on wall

MATERIALS
9. Plastic sheets
 Material :
Black polythene sheets of thickness 1mm.
 Application :
Sheets are spread and lapped 150 mm at joints
and continued across surrounding walls, under
the dpc for the thickness of the wall.
Note: It depends upon the climate and atmospheric
conditions, nature of structure and the situation
where DPC is to be provided.
Black polythene sheet used for
waterproofing

 Foundation may receive water seep from adjacent
ground and this moisture may rise in walls.
 This can be checked by providing air drain parallel
to the external wall.
 The width of air drain may be about 20 to 30 cm.
 The outer wall of drain is kept above ground
usually 15 cm to prevent water entering the drain.
 RCC cover is provided.
 Openings with grating are provided at regular
interval for passage of air.
 Top of air drain is covered with R.C.C slab or stone
slab.
 Usual DPC are also provided horizontally and
vertically.
`
TREATMENT OF FOUNDATION
(D.P.C)

 The whole of the structure below ground level should be provided with a continuous
membrane of asphalt (DPC): mastic asphalt or bituminous felt supported inside.
 It is done by spreading a layer of DPC over the whole area of the floor including the
projection of 15cm and continuing the same through external wall.
 DPC for basement must be provided in dry season when sub soli water is at its lowest
level.
 An adequate dewatering arrangement for pumping out subsoil must be provided.
 Shuttering must be provided to prevent the excavation from collapsing.
 Brick is laid flat on cement concrete to protect DPC from damage during floor
construction.
TREATMENT OF BASEMENTS
(D.P.C)

ASPHALT TANKING FOR BASEMENT

 It Is Better To Provide Trench All Around The Basement, Up To Foundation Level,
And Fill It With Gravel, Coke, And Other Pervious Material When The Foundation
Soil Is Not Properly Drained.
 In Such Type Of Soil ( Eg.Peat Soil) Due To Less Drainage, Great Hydrostatic
Pressure Is Exhausted And The Fluid As Well As Receives Water Continuously.
DPC TEATMENT FOR BASEMENT ON
UNDRAINED SOIL
LAYOUT OF DRAIN – PLAN VIEW
PROVISION OF FOUNDATION DRAINS AND
DPC

 For dry locations, a filling of 7.5 cm to 15 cm of dry course sand under the floor masonry
is done.
 A hardcore filling of stones with smaller stones to fill in voids is also quite suitable.
 The filling must be well rammed.
 A thin layer of coal tar and cinders under tiled floor act as good DPC.
 Water proofing membrane of mastic asphalt or fibrous asphalt felt , before a concrete
floor is laid.
 Generally , A Priming Coat Of Hot Liquid
Asphalt Is First Given And Then Mastic
Asphalt Is Applied In 2 Coats.
 Concrete Floor Is Reinforced If There Is
Chance Of Excessive Uplift Pressures Due To
Soil And Water Table.
TREATMENT OF FLOORS (D.P.C)

IN CAVITY WALL:
 The method of cavity wall construction is an
effective method of damp prevention.
 In this the main external wall is shielded by an outer
skin wall, leaving a cavity between the two.
 The cavity leaves a gap between walls which
prevents the moisture from traveling from the outer
to the inner wall.
 A horizontal DPC is laid 15cm above ground level.
 A layer of lead sheet, copper sheet or asphalt felt is
brought down from inner wall to the head of floor or
window to protect openings.
 Generally , a porous external treatment of plaster ,
having proportions ( 1 cement : 1 lime : 6 sand ) to
the wall is recommended.
TREATMENT OF WALLS (D.P.C)

METHODS OF APPLICATIONS

https://www.youtube.com/watch?v=3lehA6IO56w
1. MEMBRANE DAMP PROOF
In this water repellent membrane or damp proof course is
applied between the source of dampness and part of the
building adjacent to it.
It is a membrane material applied to prevent moisture
transmission. DPC may be bitumen, mastic asphalt, bituminous
felts, plastic sheet, metal sheets, cement concrete.
DPC may be provided horizontally or vertically in floors, walls,
etc.
A common example is polyethylene sheeting laid under a
concrete slab to prevent the concrete from gaining moisture
through capillary action.

An integral damp proof course involves mixing components into the
metal and concrete of the building.
The purpose of this is to fill any voids in the concrete ensuring it is
damp proof.
These may be in 3 forms,
a) Compounds of void filling material made from chalks, talc,
fullers, earth etc. Which fills the voids of concrete under the
mechanical action principle making it highly impermeable to
water due to presence of lesser voids
b) Compounds like alkaline silicate, aluminum sulphate, calcium chl
orides etc. React with concrete to produce water proof
concrete. So when these are mixed with concrete, the concrete
becomes water repellant.
c) Commercial PUBLO, PERMO, SILKA etc are available as water
repellant materials, CICO, DR. FIXIT etc.
2. INTEGRAL DAMP PROOF
https://www.youtube.com/watch?v=xYc4c2Jo9QQ

 Moisture finds its way through the pores of
material used in finishing. In order to check the
entry of the moisture into the pores, they must be
filled up.
 In the surface treatment method a layer
of water repellent substances or compounds are
applied on these surfaces through which moisture
enters.
 Sometimes, exposed stone or brick wall face may
be sprayed with water repellent solutions. The
walls plastered with cement, lime and sand mixed
in proportions of 1:1:6 is found to serve the
purpose of preventing dampness in wall due to
rain effectively.
3. SURFACE DAMP PROOF

 A CAVITY WALL CONSIST OF TWO PARALLEL
WALLS/LEAVES/SKINS OF MASONRY, SEPARATED BY A
CONTINUOUS AIR SPACE/CAVITY.
 THEY CONSISTS OF THREE PARTS: OUTER WALL, CAVITY/AIR
SPACE(5CM-8CM) INNER WALL.
 THE TWO WALLS FORMING A CAVITY IN BETWEEN MAY BE
OF EQUAL THICKNESS OR MAY NOT BE.
4. CAVITY WALL CONSTRUCTION

 This consists in forming an impervious layer of rich
cement mortar(1:3) for water proofing over the
exposed concrete surface for resisting water
pressure.
 Gunite is a mixture of cement and sand, the usual
proportion being 1:3 or 1:4.
 A machine known as cement gun, having a nozzle
for spraying the mixture and a drum of
compressed air for forcing the mixture under
desired pressure.
 Any surface which is to be treated is first
thoroughly cleaned of any dirt, grease or loose
particles and then fully wetted. The mix of cement
and sand is then shot under a pressure of 2-3
kg/sq.Cm by holding the nozzle of cement gun at a
distance of 75-99 cm from wall surface
5. GUNTING DAMP PROOFING
The impervious surface should be watered
for about 10 days.

WC WATERPROOFING
• The pre-work should be completed before starting the
water-proofing :
• Completion of internal plaster of walls leaving a margin
of 18” from the final floor level of WC unit.
• Completion of grooving or chasing for concealed G.I.
piping or electric conduit piping in WC.
• Removing of all debris from WC and chiseling the extra
mortar to expose the rare slab completely.
• Completion of making holes in external walls for
connecting nahini trap, p-trap, floor trap, etc to the
external drainage line.
• Thorough cleaning of WC with sufficient quantity of
water.
• Level marking in red color on wall with respect to floor
level to setup trap level.

WC WATERPROOFING
Coating for WC water-proofing
Provide 25-40mm thick cement mortar base coat in proportion 1:4
with a slope of 1:100 from the entrance door towards the water
escape pipe (drain pipe).
Carry out this base coat on all walls upto a height of 45cm above
toilet finished floor level
Keep this base coat full with water upto the slab drop top, for
minimum 4 days for curing and testing purposes.
Brick coat for WC water-proofing
Lay the brick bat on the edge and not on the flat surface.
Complete the brick bat coat with joints filled with cement mortar
in 1:6.
Give a slope of 1:100 in brick bat coat from the entrance door to
the water escape pipe.
Cure the coat by ponding water for four days and check for any
leakages.

BATHROOM WATERPROOFING
After completion of the internal plastering of walls, keep a
margin of 450mm from the final floor
level of the bathroom. Roughening of the plaster should be
done with a wire brush for fixing the
glazed tiles cladding dado.
Complete grooving, chiseling for concealed G.I and
electrical conduit piping in bathroom.
Remove all debris from the bathroom after chiseling the
extra mortar, if any, to expose the slab
completely.
Make the holes in the external walls for connecting nahini
trap to external drainage line and water
leakage drain pipe.
Clean the bathroom thoroughly with water. Mark the level
in red on the walls, with respect to the
floor level, to set up the trap level.

THANK YOU….

WATERPROOFING and DPC in structure and building

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