Fosroc Supercast SW20

Product Overview

Supercast SW20 is part of the Fosroc Supercast SW range of hydrophilic swellable waterstops, manufactured from high-performance synthetic elastomer strips. The swelling action results from contact between water and hydrophilic groups that are an integral part of the polymeric structure. These groups are not subject to extraction and maintain swelling performance through prolonged or repeated wetting. Expansion creates positive pressure against the concrete joint faces to prevent water passage. Swelling in fresh concrete is minimal, with a delayed swell action that helps prevent premature swelling during wet site conditions.

Features

• Easy installation — bond with adhesive or cast into joint faces; no complex shuttering required
• Damp substrate application — Supercast SWX and SW Adhesive can be applied to damp surfaces
• Complex detailing — can be linked to Supercast PVC waterstops to maintain network continuity
• Reversible swelling — performance unaffected by long-term wet/dry cycling
• Salt tolerant — suitable for use in concrete and groundwater containing salts
• Sustained seal — maintains effective sealing in wet conditions
• Highly adaptable — rectangular-section strip accommodates complex joint shapes
• Delayed swell design — prevents premature swelling in wet site environments after installation

Applications

• Integral sealing of construction joints in cast-in-situ concrete
• Complex locations where conventional PVC waterstops are difficult to install
• Diaphragm wall and secant piled basement structures
• Pile cap waterproofing
• Joints between new and existing concrete
• Pipe entry waterstop detailing
• Vertical construction joints and kicker joints

Certifications

• British Board of Agrement (BBA) Certificate No. 5450 (per manufacturer)
• Approved for contact with potable water per BS 6920:2014 and WRAS certified (per manufacturer)

Application Guidelines

• Surface preparation — concrete substrate must be clean and free of standing water
• Cut and install — cut to required length and bond to joint face with Supercast SWX or SW Adhesive
• Rough surfaces — use Supercast SWX adhesive on rough concrete surfaces
• Jointing — use butt joints; overlap or sidelap joints are not recommended
• Adhesive curing — allow adhesive to fully cure before placing concrete; do not immerse during curing
• Pre-pour inspection — check for detachment, displacement or distortion from premature swelling

Packaging

Red rectangular-section strip, supplied in rolls

Notes

• Not suitable for expansion joints or joints subject to significant movement
• Swell rate is affected by water quality and temperature
• Do not use where free unrestrained swelling can occur or for free-standing walls
• Must not be immersed in water before concrete placement, though SW20 tolerates short-term damp exposure
• No known health hazards in normal use (per manufacturer)
• Shelf life: twelve months in original unopened packaging stored in cool, dry conditions (per manufacturer)
• For detailed application methods, coverage rates and technical parameters, refer to the official product data sheet

FAQ

What is the difference between SW20 and SWX?

SW20 is a pre-formed waterstop strip for primary sealing of long, straight construction joints. SWX is a gun-applied swellable paste that can serve as adhesive for SW20 and also as a standalone waterstop for irregular shapes and detailed locations. SW20 for straight joints, SWX for complex details — they are often used together.

What advantages does it have over conventional PVC waterstops?

SW20 is much simpler to install — just bond or nail-fix in place without complex formwork. Conventional PVC waterstops must be pre-fixed within shuttering, requiring more labour. SW20 is particularly suited to locations where traditional waterstops are difficult to install, such as diaphragm walls, secant pile basements, pile caps and irregular joints.

Which to choose: SW10, SW20 or SW30?

The three grades differ in cross-section dimensions and swell ratios, suited to different water pressure and concrete cover requirements. SW20 is the most commonly used grade and is BBA certified. Select the appropriate grade per engineering drawings, or contact us via WhatsApp.

How much does it cost?

Please contact us via WhatsApp for pricing. Available for pickup at our Mong Kok store or delivery within Hong Kong.