1. Water Proofing
• Waterproofing defined
• Importance
• Methods ( Conventional )
• Methods ( Modern)
• Waterproofing of Basements
• Terraces
• Bathrooms & W C
• Chemicals used for waterproofing treatment
• Role of Consultants
2. Background
• The most widely and effectively used construction
material in world today is concrete, beside steel and
wood.
• Making good concrete in the laboratory is not at all
difficult.
• But at the site, it is possible to make concrete
waterproof.
• Ideally, the concrete is supposed to be watertight, if it
is done in a manner in which all the parameters are
followed strictly.
• But, in practice, concrete is quite porous
3.
4. Waterproofing Meaning
• “Any system or material (s), which helps in preventing
ingress of water into structures can be broadly termed as
waterproofing.
• Waterproofing is often misused and misunderstood term
• Waterproofing is defined as treatment of surface or
structure to prevent the passage of water under the
hydrostatic pressure
5. IMPORTANCE OF WATERPROOFING
• If we refer back to the definition of waterproofing as an impervious
barrier designed to prevent water entering or escaping from building
structures.
Problems caused by water
• Rotting of timber structures and finishes such as floor joints, beams,
floors, studs, skirting, architraves and frames.
• Corrosion of metals such as steel reinforcement in concrete, steel
beams, lintels, metal door frames etc.
• Swelling of plasterboards and the subsequent debonding of ceramic
tiles.
• Electrical hazards causing the possible short circuit of lighting and power
points.
• The blistering of paint.
• Unsightly deterioration of the building facade.
• Health problems due to dampness, which may lead to respiratory
problems.
•
6. Source & Causes of leakages
Sources of leakages
• Subsoil water rising by capillary action.
• Cracks in external plaster
• Vegetation growth
• Separation gaps between partition wall and beams and the
columns.
• From expansion joints
Causes of leakages
• Defective structural design
• Use of poor quality construction material
• Porous structures
• Improper methodology of construction
• Improper slopes on top surfaces.
7. Review of Conventional Waterproofing
Systems
• Brick Bat Coba system or Lime Terracing
• Bituminous Treatment/Systems
• Metallic Sheet Wrapping
• Poly-urethane based Water- proofing
treatment
• Epoxy Based Waterproofing Treatment
• Box Type Waterproofing System
8. Brick Bat Coba system or Lime Terracing
• This system was developed during the initial stages of
flat roof construction with lime mortar & burnt clay brick
aggregate
• This system involved laying of lightweight mortar on the
roof and spreading it to give gentle slopes for draining
away the rainwater immediately. The mortar consisted
of lightweight brick pieces as aggregates and ground
brick with lime as binding matrix
9. Brick Bat Coba system or Lime Terracing
• Procedure
• All existing treatment, coatings on roof slab top is to be removed
and surface cleaned by hard wire brush and washed with water.
• The surface should be free from any oil, grease, dust etc. Remedial
measured by provided to all structural cracks.
• Expansions joints should be treated as per standard practice
• All non-structural cracks more than 0.5 mm wide and construction
joints if any, should be cut in “V” shape, cleaned with wire brush and
washed, the cracks are then filled by polymer modified cement or
mortar using acrylic polymer, with addition cement slurry mix is
spread upon cleaned SSD roof surface. Over this 15 mm thick
cement, sand mortar, 1:4 admixed, with water proofer is laid.
• On the above green mortar, a layer of brick bats, soaked over night
in water, is laid, having an average thickness of about 110 mm,
about 70 mm near rain water pipe and 150 mm at ridge.
10.
11.
12. Brick Bat Coba system or Lime Terracing
• Limitations :
This system has following limitations
• There is a possibility of improper compaction
• Chances of crack development on the top
surface.
• Brickbat coba is a source of water retention
and absorption.
• If slab has cracks the retained water may leak.
• The absorbed water may allow penetration to
the slab level.
13. Bituminous Systems
• Bitumen is more commonly used in the form of felt or
flexible membrane formed by sandwiching jute fabric
or fibre glass/polypropylene mats with chemically
modified bitumen.
• These membranes are laid on the roofing system over
a bitumen primer.
• There are two types of membranes one is cold applied
and the other is hot applied which means one needs to
heat the edges of the felt ,so that they melt and stick to
the second layer in the overlap area.
• On the RCC flat roofs, the bitumen felts have not been
successful because of the unacceptable black
appearance and inaccessibility of the terrace for other
social uses
14. Bituminous Systems
• There are certain essential pre-requisites for any bitumen based water
proofing system to be successful.
• The surface to be treated should be smooth, having proper slope.
• There should be no depression or cracks
• The surface should be dry.
• Any structural defaults in the roof or the parapet wall should be
attended to before starting the treatment.
• Detailed steps in laying of the bitumen based surface barrier systems
will
i) Make surface smooth, even and dry, remove local depressions and
loose dirt.
ii) Paint the dried surface with bituminous primer and allow it to cure.
iii) Apply foundation coat of bitumen.
iv) Lay surface barrier membrane i.e. bitumen felt.
v) Apply on coat of bitumen and finish with grit or coarse sand.
15. Bituminous Systems
• Technically, it is not preferred because bitumen layer or felt on the
terrace not only makes it watertight but also airtight. Concrete has the
breathing property.
• It takes water/moisture and breathes out water vapour.
• Hindrance of this breathing property of concrete develops pore
pressure which causes blisters in the felt.
• After a few seasons, the blisters multiply and eventually delaminate the
felt from the concrete surface.
• Hindrance of breathing property of concrete, makes the concrete weak.
• But on the asbestos cement sheets and zinc sheets in factory roofs, this
bitumen felt is the only dependable waterproofing system. Hence most
of the factory roofs in India adopt this waterproofing system Bitumen is
still the product of first choice where it is commonly recommended, in
areas such as industrial roof waterproofing, basement water- proofing,
and damp-proof course.
• Moreover, bitumen is the most economical product presently available
for waterproofing
16. Polyurethane Based Waterproofing Treatment
• Polyurethane consists of two liquid components one is called the
Base component and the other is called reactor or curing agent
• Base is a polyol and the reactor is an isocyanide.
• The combination of these two ingredients results in a formation
liquid applied rigid membrane or a foam depending upon the
selection
• In waterproofing, this rigid liquid membrane was tried with fibre
glass reinforcing mats. The systems failed because coefficients of
thermal expansion of concrete and rigid PU membrane being
different lateral movement or creep occurred with the passage
on one working climatic cycle. When exposed to ultra violet rays
or direct sunlight, most polyurethane rigid membranes became
brittle and crumbled. Apart from this, the application of
polyurethane coating needed very rigorous surface preparation.
• Surface Preparation : needed, neutralization , alkalinity.
17. Epoxy Based Water- proofing System
• Like polyurethane epoxy is also a two-component system having
a base resin and a reactor or curing agent.
• Base resin is obtained by dissolving Bis-phenol ‘A’ flakes in
epichlorohydrin. This base is available in various viscosity ranges
to suit different application conditions.
• The curing agent is an amine/polyamine aliphatic or aromatic or
an amine-adduct for general applications and polyamide or an
amino-amide for coating purposes.
• After mixing base and reactor components, the resultant
viscous liquid or paste if some fillers are added to it can be brush
applied like a paint or trowel applied like a mortar.
18. Box Type Waterproofing
• This type of waterproofing system is used only for basement
waterproofing or structures below the ground level from outside
to prevent leakages of subsoil water into the basement.
In this method, limestone slabs (Shahabad Stones) are first laid in
the excavated pit over blinding concrete in a staggered joint
fashion to avoid the continuity of the mortar joints.
• The joints are effectively filled with rich cement, sand mortar
admixed with integral waterproofing compound and cured. Over
this, the raft is laid and shear/brick walls constructed.
• The limestone slabs are erected around the walls in a similar
fashion leaving a gap of one to two inches between the external
surface of the wall and the inner face of the stone surface.
• The joints again effectively sealed with rich admixed mortar and
the same mortar is filled in the gap between the wall and the
stones. This stonework is continued up to ground level.
19.
20. Box Type Waterproofing
• In this system, the raft and the sidewalls are protected from
direct exposure to sub soil water
This system works on two principles of common sense.
• First the area exposed to subsoil water is only the area of the
joint where as the whole stone is impervious to water, hence
only a fraction of area, that is, that of the joint is exposed to
subsoil water when the joint itself is filled with rich and
quality mortar.
• Secondly, the path of water to reach the raft or the sidewall
is elongated. This elongated path is through quality mortar.
This system seeks to delay the occurrence of leakages in the
basements. A lot of building structures are waterproofed
using this system. A few notable successes are to its credit
especially in five star hotels and of-course there are a few
failures as well.
21. Box Type Waterproofing
• For basements, Swimming Pools and under-ground ducts such
as lift-pits, the waterproofing has to withstand the water
pressure in addition to it’s basic stress. Shahabad Box Type
treatment method of waterproofing is very commonly used in
India.
• A base-coat in cement mortar 1:4 mixed with waterproofing
compound is laid over the Raft PCC and above this rough
Shahabad tiles of size 2’-0” X 2’-0” or 2’-0” X 3’-0” are fixed
with minimum thickness of joints.
• Joints are staggered. Thickness of the Shahabad tile should be
between 32mm to 40mm (1.25”-1.5”). After fixing the tiles, the
joints are sealed with C.M. 1:3 and 15mm metal is pressed in
the joints for enhanced strength and less shrinkage.
• Over this, a joint less layer of C.M. 1:3 with waterproofing
compound approx. 25mm thick is applied and cured for 7 days.
This layer provides a smooth layer for the raft and also protects
the Shahabad tiles from getting damaged by steel bars laying
and labour movement.
22. Box Type Waterproofing
• Over this plastered base, raft is cast and RCC retaining
walls are erected. Shahabad tiles are fixed to the
vertical retaining walls from outside. Cement paste is
applied on all four corners of a Shahabad tile and it is
pressed firmly on the RCC wall in line and level. At a
time only a height of 1m is fixed.
• Total height above the ground level is taken as 1’-6”.
Joints are then sealed in C.M. 1:2 (Pointing). The
Shahabad dado is then grouted using cement slurry with
waterproofing compound and cured for 7 days.
• After curing, a jointless waterproofing plaster coat is
applied and cured. Thickness of this treatment is around
65mm to 75mm.
• This entire process forms a box around the structure
and does not allow any water to seep through or leak
from the basement.
26. Box Type Waterproofing ( Basement waterprofing)
Limitations/Disadvantages
• Use of Shahabad tiles, joints should be grouted properly or else the
leakage would be from the joints.
• It is a labour intensive work for which it requires more time for
installation
• Waterproofing membrane such as
• Bituminous, polymer modified bituminous of APP (Atactic Poly
Propylene)
• SBS (Styrene Butadine Styrene), PVC, HDPE can be used for basements
• Since APP membrane is torch applied, it requires more skilled labour
and a protective screed to avoid any damages to the membrane.
• SBS is cold applied by simply sticking with a paste. But it is not suitable
for high water table. It also requires a screed for protection
• HDPE is the best material for waterproofing in high water table.
27. Modern Techniques in Waterproofing
• Modern technique aims to understand the functional
behavior of the structure, understand the properties of
the available materials to arrive at a system, which is
best suited for the structure and incorporate the design
stage itself.
• A single product or technique is not usually enough,
involvement of various bodies and techniques in
coordination is essential for making structures
waterproof.
• For success of any system, the building structure should
have sufficient and efficient control joints if the slabs
dimensions are more than twenty meter in any
direction.
• Crystalline Waterproofing System
• Flexible membrane waterproofing system
28.
29. Crystalline Waterproofing System
• The method of treatment involves saturating with water the
surface to be treated.
• Then mixing two and half volume of the powder with one
volume of water to form neat consistency hot slurry.
• This slurry is brush applied on the saturated surface. The
active ingredients in the slurry pass through the water
bearing capillaries and react with calcium oxide present in
the concrete to form insoluble crystals, which effectively
block the capillaries.
• Further the chemical ingredients of the product remain in
concrete to reactivate the process of crystallisation and
when a new capillary is developed.
• This system of waterproofing, the water retaining structures
is practiced in most of the developed countries
30. Crystalline Waterproofing System
• The waterproofing effect is based on two simple reactions, one chemical
and one physical. Concrete is chemical in nature. When a cement particle
hydrates, the reaction between water and the cement causes the concrete
to become a hard, solid mass.
• The reaction also generates chemical by-products such as calcium
hydroxide, sulfates and carbonates of sodium potassium and calcium as
well as un-hydrated or partially hydrated cement particles all of which
reside in the capillary tracts of the concrete.
• Crystalline waterproofing introduces another set of chemicals to the
concrete. When these two chemical groups, the by-products of cement
hydration and the crystalline chemicals, are brought together in the
presence of moisture, a chemical reaction occurs. The end product of this
reaction is a non-soluble crystalline formation.
• This crystalline formation can only occur where moisture is present, thus it
will only form in the pores, capillary tracts, and shrinkage cracks of the
concrete. Wherever water goes, crystalline waterproofing will form filling
the pores, voids and cracks.
31. Crystalline Waterproofing System
• Cracks if any should be cut into ‘V’ shaped grooves one inch wide and
proper size width & depth Cut honey combed areas back to sound
concrete.
• Repair these areas first by priming with crystalline waterproofing slurry and
then by filling them with crystalline modified mortar produced by mixing
crystalline waterproofing powder OPC and zone II sand in the proportion of
1:1:4 and water enough to produce a stiff consistence paste. Allow the
repair mortar to dry.
• Thoroughly sprinkle water on the area to be treated till the surface
becomes saturated. Some recommend overnight ponding for effective
results
• Prepare crystalline waterproofing slurry by mixing the powder and water in
the proportion of two and half volume of powder to one volume of water
to form a hot slurry. Brush apply this slurry on the water saturated surface
in two coats.
• When the second coat is still wet plaster the surface with 1 : 4 cement sand
mortar admixed with an integral waterproofing compound and cure
properly.
32. Flexible Membrane Waterproofing System
• The main product used in this system, comprises two
components one liquid and the other is a powder packed roughly
in the proportion of 1:4 by weight. The liquid component is an
acrylic emulsion and the powder component is a polymer-
modified cement with film forming chemicals and fillers
• When these two ingredients namely the pre-weighed powder
and the liquid are mixed together an uniform slurry results.
• This slurry is brush applied on the roof surface, which upon drying
forms a flexible film. Since there is cement in this product, its
compatibility with concrete is excellent.
• The film further allows the breathing of the concrete without any
hindrance hence there is no problem of its de-lamination from
the concrete surface.
• This film being flexible takes care of the deflections in the slab
and the movements caused because of primary or secondary
settlements, movements due to wind loads and temperature
stresses developed in the concrete
33. Flexible Membrane Waterproofing System
• Cracks if any should be cut into ‘V’ shaped grooves of
a proper size in depth. Cut honey combed areas back
to sound concrete.
• Repair these areas with a stiff paste of fibre
reinforced polymer repair mortar generally sold in the
name of crack fill.
• Mix the powder and the liquid components of the
product to form an uniform slurry and brush apply
this slurry on the surface to be waterproofed.
• When the waterproofing coating is still tacky apply 1 :
4 cement sand screed and cure normally
34. Membrane Selection
When selecting a membrane it is essential to consider a number of relevant
factors including:
• Whether the membrane will be exposed to weather or protected by
subsequently applied floor finishes
• The type of floor finishes and adhesives that will be applied
• The exposure conditions of the membrane (e.g. coastal or other aggressive
environments)
• Anticipated substrate movement
• Ambient weather conditions (some membranes must be applied within
specific temperature and humidity ranges)
• The durability of the membrane
• Ongoing maintenance requirements
• Availability of specialist contractors to apply certain systems
• Ease of application
• Re -coating time and time before subsequent finishes can be applied
• The moisture content of the substrate.
35.
36. The Latest Trends in Waterproofing
The following methods can be used to achieve this:
1. Use of Water tight concrete
2. Liquid Applied Membranes
Use of Watertight Concrete
Blocking pores/capillaries in the concrete can be done using
the following methods:
1. Using high performance PCE polymers
2. Use of materials like Silica-fume or Aluminosilicate slurries
in concrete
3. Use of highly specialized latest generation Integral
waterproofing compounds that work on process of
Dynamic SynCrystallization® (DySC) technology
37. • Using high performance PCE( Polycarboxylate Ether ) polymers
The Latest Trends in Waterproofing
38. • It is well known that using PCE polymers, give excellent water
reduction as compared to normal plasticizers.
• This helps to reduce the w/c ratios and cement contents, even in
normal concretes. Lower the w/c ratio, lower are the number of
capillaries in concrete.
• PCE based admixtures do not have the side effects of retardation
often seen with normal retarding super-plasticizers. This is beneficial
as workability time of concrete can be controlled but the hydration
and setting of concrete will proceed unhindered.
• This ensures that any subsequent vibration to concrete after initial
set will not open up capillaries, as is the case if concrete is retarded
for a very long period of time, thereby rendering concrete relatively
waterproof
The Latest Trends in Waterproofing
39. • Use of materials like Silica-fume or Aluminosilicate
slurries in concrete
• Condensed Silica Fume or Aluminosilicates are extremely fine
materials that function both as microfillers as well as
pozzolanic materials that hydrate in the presence of the
Calcium Hydroxide in Concrete.
• The combined effect of these materials as microfillers and
hydrating materials help close capillaries in concrete, thereby
rendering it waterproof
The Latest Trends in Waterproofing
40. Role of Waterproofing
• The membrane must be impermeable to prevent the
passage of water.
• Flexibility - membranes need to accommodate any
normal movement that may occur in building
structures.
• The membrane must be durable, it must be able to
retain it's integrity over a long period of time.
• The membrane must lend itself to design details in a
building. It must be suitable for each specific
application. The membrane is useless if it cannot be
applied where needed because of structural details.
• The membrane must be able to breathe permitting the
escape of moisture vapours from building interior and
substrates.
41. Role of Waterproofing
• The membrane must be compatible with adhesives to
ensure long term adhesion where tiles are directly
fixed over the membrane.
• User friendly, the membrane must be easy to apply,
relatively lightweight, non hazardous, and
environmentally safe.
• In exposed areas such as rooftops, the membrane
should require little maintenance, and in the event of
damage must be easily repairable.
• It should provide a continuous film, without areas of
weakness such as overlaps, which could prove to be a
potential source of water entry.
• The membrane must be suitable to withstand
environmental and climatic conditions.
42. Precautions to be taken by the Client and
Consultant
• Selection of an effective waterproofing system for a
structure taking all the performance criteria of the
structure into account and also taking into the
consideration, the performance of the materials in
the system is of prime importance for any success of
the waterproofing job.
• Waterproofing jobs awarded to waterproofing
contractors purely on economical price
considerations often fail.
• It is always advisable to involve the architect or the
structural engineer in selection of a system and
requisite performance guarantees should be taken
from the contractors.
43. Precautions to be taken by the Client and Consultant
• It is better to avoid bargaining for the job value
out of contractor’s margins. This could result in
stretching the product beyond the coverage
specified by the manufacturer or substitution of
cheaper material in the system to cover the cost.
• Always supervise the job and the incoming
materials for the intact tamperproof seals and
quantities.
• Use the services of an engineer or architect in
selection of materials. That too only procured
from well know manufacturing firm.
44. Failure of Waterproofing Systems
• Application of a waterproofing product in non-
specified areas, such as using a crystalline
waterproofing system in waterproofing the
terrace or using a flexible membrane system in
the water tank results in failures even though
the products themselves may be genuine.
• Stretching the coverage of the products
beyond the specified limits by the
manufacturer results in inefficiency of the
product and hence a failure.
