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UNISTOP™ PVC PVC WATERSTOP
PROFILES AND WIDTH SELECTION GUIDELINE
The general rule of thumb is that for concrete wall or slab thicknesses of 250mm & above use a 250mm wide
waterstop profile. For width less than 250mm, use either 150mm or 200mm profiles to match as near as possible the
thickness of the wall or slab.
UNISTOP™ ICJ or UNISTOP™ IEJ internally placed waterstops are always used in wall joints in water retaining
structures, and can also be used in roof & podium deck joints or wall joints in water excluding structures.
UNISTOP™ ECJ or UNISTOP™ EEJ externally placed waterstops are generally used when there is positive water
pressure directly on the waterstop, particularly in water excluding structures such as basements, tunnels etc. But are
also used in base slabs in water retaining structures.
INSTALLATION PROCEDURES
All waterstops must be securely fixed to avoid moving during concrete placement. Failure to achieve this will result in
misaligned waterstops.
Prefabricated intersections shall be heat jointing to straight lengths prior to fixing on site.
Concrete must be fully compacted around the waterstops to ensure no voids or honeycombs.
PREPARATION
Long term durability and function can only be achieved with good preparation & application to give a continuous
waterstop network throughout the structure. Ensure the surfaces where the PVC waterstop is to be place are
clean and free from sharp projections. Unroll the waterstop along the line of the joint & cut to length allowing or
appropriate intersections as required.
FIXING INTERNALLY
UNISTOP™ ICJ or UNISTOP™ IEJ internally placed waterstops are positioned within the concrete where the
centerline o f the waterstop is aligned with the centre of the joint, and fix in place using wire tied to the steel
reinforcement through the eyelets provided at the end flange, along the length of the waterstop roll. The formwork
should be securely erected either side of waterstop so as clamp it in the middle of where the concrete will be
poured.
To create expansion joints, cast one side of the concrete first, then securely fix UNIFLEX PE™
(polyethylene fillerboard) to the concrete faces either side of the PVC waterstop centre bulb for the full depth of
the joint, before casting the next piece of concrete directly against the UNIFLEXPE™.
FIXING EXTERNALLY
UNISTOP™ ECJ or UNISTOP™ EEJ externally placed waterstops are usually laid on top of the compacted grade or
lean concrete. The stop end form works are then fixed on top of the waterstop. It is fix in place by nailing the
waterstop through the outer reinforced web to the formwork along its length to avoid displacements during the
concrete pour.
To create expansion joints, cast one side of the concrete first, then securely fix UNIFLEX PE™
(polyethylene fillerboard) to the concrete face on top of the PVC waterstop centre bulb for the full depth of the
joint, before casting the next piece of concrete directly against the UNIFLEXPE
JOINTING
UNISTOP™ PVC WATERSTOP rolls and intersections must be hot welded together using a suitable jig and electric
heating blade prior to placement. Different jigs should be used depending on the profile and width of waterstop
used.
The edge of the waterstop shall be cut with a knife to get an even and sharp finish and aligned in a specially
designed fixing jig. The edges will then be positioned in the jig in such a fashion that at least 25mm of waterstop
protrudes from the jig. Place the heater blade in between the PVC ends and close the jigs together so the ends
touch the heater blade.
Turn on the heater blade and allow it to melt the PVC either side. When the PVC starts melting, beads will start
forming around both sides, remove the heater blade and press both the ends firmly against each other to form a
neat buttsplice. Press the joints against each other for sometime till the PVC cools and forms a strong fusion
welded joint.
