Preventing Water Leakage
through Construction Joints
in RCC Water Contact Structures
PREFORMED
COMPRESSIBLE
WATERSTOPS
Overhead Water Tank
Sources of Water Leakage
Construction Joints
Sump Tank, Swimming Pool, Sewage Treatment Plants………..
Sources of Water Leakage
Inclined Construction Joint
Construction Joints
Horizontal Construction Joint
Construction Joints
Vertical Construction Joint
in Final Roof Slabs which cannot be cast in one go
Water may Leak through the joint shown by dotted line
Construction Joint
Vertical Construction joint in Basement
Sources of Water Leakage
Construction joint
Basement Construction Joints
Sources of Water Leakage
Wall Floor Joint and all around columns
Construction Joints are present in…..
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Overhead Water Tanks
Swimming Pools
Basements
Underground Reservoirs
Water Treatment Plants
Sewage Treatment Plants
Typical Construction Joint for
Basement
Vertically Held Vibrator
unable to consolidate
concrete here hence
Construction Joint gap
Water enters here
The Nagging Problem
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Leakage of water through the
improperly executed Construction Joint
Swimming Pool Leakage
from bottom joint
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Basement Leakage
Please observe leakage around column base when ground water table rises
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Stopping Water Leaks
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Engineers have tried various methods to
solve this problem
- during Concreting
- after Concreting
Painting with Epoxy
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Painting with epoxy bonding agent
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Question: How can a gap get filled with a coat
of epoxy ?
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Debonding is not the problem, existence of a
gap is the problem
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Hence Unsuccessful method
PVC Waterbar sketch
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The next slide is a 20 second movie slide. Kindly wait a
few seconds for it to start playing.
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Please go to the next slide only after concrete pours
onto the PVC water bar.
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It shows problems that a PVC waterbar can create and
after that, contrasts it with a preformed waterstop.
Thank you.
PVC Waterbar
PVC Waterbar Problems 1
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Half of it has to be inserted during concreting
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Generally difficult to insert due to obstruction
by rebar
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Folds over during next lift of concreting and
forms a tunnel in which water can leak
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Never bonds with concrete
PVC Waterbar Problems 2
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End to end should be spliced with PVC Welding
equipment which is generally not available at site
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Different sizes of strips have to be maintained to
resist different heads of water. Chances of mix-up
are very high
After Concreting
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Grouting into Construction Joints
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Generally unsuccessful
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Expensive, tedious, time consuming
The Right Approach
SYNKOFLEX
Compressible
Flexible
Waterstop
SYNKOFLEX Compressible Flexible Waterstop
SYNKOFLEX Compressible Waterstop
Waterstop Application
A Simple Solution
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The next slide is a 15 second movie slide. Kindly
wait a few seconds for it to start playing.
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Please note how concrete flows all around the
Synkoflex and seals the joint with Synkoflex acting
like a gasket. Such a compressed seal will never
fail.
Laying Synkoflex
cross sectional view
How to use - 1
How to use – 2
How to use - 3
Application of SYNKOFLEX Waterstop
in Basement Construction Joints
a) Wrap Synkoflex around column base.
b) Also stick to wall along the perimeter of basement
RETAINING WALL
FOOTINGS
RAFT SLAB
Application of SYNKOFLEX Waterstop
in Final Roof Joint
After first phase of concrete pour, stick Synkoflex as shown and
then continue with the second pour to get a 100 percent leak free
joint
WATERSTOP
Vertical joints – Nail the Synkoflex
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Pipe Joints
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Laying Synkoflex in basement joints
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Synkoflex
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Single component, self sealing compound
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Packed between two self release wrappers
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Bonds to cured concrete
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Fuses with fresh concrete during hydration
Properties of Synkoflex - 1
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Environmentally Safe
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Can be used for drinking water tanks
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Does not depend on chemical action, swelling,
oxidizing for its action
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Flexibility of Synkoflex is forever
Properties of Synkoflex - 2
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Never shrinks, cracks or dries out
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Inert to acids, alkalies and sewage
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Can be stored indefinitely
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Can be laid using unskilled labour
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Need not be laid when concrete is green
Effectiveness
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Designed to resist water head of 20 mtrs (65 feet) of
water when placed in properly designed and
compacted M 20 grade concrete
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Tests have confirmed that Synkoflex is effective
upto 32 mtrs (105 ft)
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TRFI test confirms unequivocally for 20 mtrs water
head
Effectiveness
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In extreme cases, can be used even
under standing water
Used since 1968 in
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Tunnels
Potable Water reservoirs
Sewage Treatment Plants
Fish Hatcheries
Waste Water Treatment Plants
Swimming Pools
Water Tanks
Where else to use
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Joint between Old roof and new roof
Joint between Column and Floor when new
floor is being cast
Basement Floor (Raft Slab) Horizontal Joint
Basement Wall Vertical Joint
Where else to use
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Topmost roof cast in two pours
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Any joint between Old Concrete and new concrete
provided thickness of concrete member is more
than 150 mm
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Pipe intrusions in Basement Retaining Walls
Where not to use
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Expansion joints
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Tanks which store petroleum based liquids
Case Study – Reservoirs
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200 reservoirs built by Govt. of
Karnataka
No construction joint is leaking
Case Study – Old,New RCC
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Landmark building in Karnataka
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Was required to abut new roof to old roof
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About 150 mtrs of Synkoflex used
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No leakage anywhere
Case Study – Swimming
Pool
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Swimming Pool built on fifth floor roof by
leading developer in Bangalore
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No leakage through construction joint
Case Study - Basement
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Leading Jeweller in Chennai
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Double basement
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Synkoflex used in joints
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Basement is bone dry
Synkoflex Packing
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Cross section 20 mm x 20 mm
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1 mtr strips x 25 nos per box
The Low Cost of Success
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For a Water treatment plant measuring 8 mtr x 32
mtr x ht 6 mtr volume about 1.5 million ltrs of water
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Joint length assumed as about 200 mtrs depending
on concreting scheme
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Cost of water tight joints is about Rs. 70,000 which
is a negligible cost of the total project cost (Rs. 50
lakhs) 1.4 %
TESTS
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Successfully tested by CFTRI, Mysore for
potable water safety
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Successfully tested by TRFI for resisting
water head of 20 mtrs
Conclusion
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Compressible Waterstop enables a
100 percent watertight seal
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SYNKOFLEX Waterstop is a
permanent solution to stop leakage
through construction joints
THANK YOU