Where high water tables exist in deep basement construction and the highest possible watertight design is required, then Fosroc Supercast Twinstop is recommended.

Fosroc Supercast Twinstop is a combined PVC and hydrophilic waterstop for extra protection. The PVC profile performs as normal but when water reaches the hydrophilic inserts, they expand to form a sealed barrier.

The hydrophilic inserts are based on Fosroc’s basic polymer swellable compound which is post-inserted into the PVC waterstop meaning there is no chance of pre-swell prior to concrete casting. The hydrophilic insert has a large surface area allowing excellent swelling performance.

Fosroc Supercast Twinstop is available in 250mm width for both centrally and externally placed expansion joints.

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• Features & Benefits
• Application Notes

Features & Benefits

• Hydrophilic elements are treated with a delay swell coating to avoid problems associated with hydrophilic pre-swell
• Fully continuous four-bulbed network
• Complete integration with existing PVC
• Patented, reinforced eyelet edge flanges for positive fixing
• Cost-effective alternative to co-extruded waterstops
• Range of fabricated intersection pieces
• Hydrophilic elements have been designed into the system in the optimum position
• Can be used in situations where salt water, sewage, agricultural silage, oil, diesel and petrol are prevalent
• Tolerant of site conditions — if damage does occur to hydrophilic elements, they can simply be removed and replacements slotted in
• Specially designed to provide significant advantages over co-extruded hydrophilic waterstops
• enables the PVC waterstop to be fixed on site in the usual way and provides the additional benefit of two hydrophilic elements treated with a retarded swell coating, thus avoiding the common problem of hydrophilic pre-swell on site
• Suitable for use in contact with potable water and is a Water Regulations Advisory Service approved product
• made from extruded plasticised PVC compound which meets the US Corps of Engineers specification CRD-C 572-74. When tested to BS 2782 at 25°C, it has a tensile strength in excess of 14 MN/m² and an elongation at break in excess of 300%

Application Notes

• Supercast Twinstop and Twinstop Intersections can be jointed together using a Fosroc Electric Welding Blade and Supercast Jig
• Waterstops must be installed so that they are securely held in their correct position while the concrete is being placed
• Concrete must be fully compacted around the waterstops to ensure that no voids or porous areas remain
• Where reinforcement is present, an adequate clearance must be left to permit proper compaction
• Care should be taken to ensure that the hydrophilic inserts are not exposed to excessive rain or puddling before the concrete pour. If this does happen and damage does occur to the hydrophilic element, the damaged hydrophilic can simply be removed and a replacement tooled in
• Concrete should never be poured onto a pre-activated hydrophilic strip

Supercast Rearguard TS 250mm

• When used on ground slabs where the waterstop is supported on blinding, the Rearguard profile usually requires no fixing
• Lay the waterstop centrally over the line of the joint to be formed
• Fixing to vertical shuttering is done by nailing through the outer nailing flanges leaving the head of the nail proud so that it is held in the cured concrete. This prevents the waterstop being displaced when the shuttering is struck

Supercast Hydrofoil TS 250mm

• The brass eyelets used for securing the waterstop are located outside the edge bulbs so as not to create waterpaths around the profile
• The Hydrofoil profile should be positioned with the hydrophilic inserts on the water facing side