Fosroc Supercast Injectoseal
A re-injectable, integral-valve hose cast into concrete construction joints to seal watertight structures against water and saltwater ingress, injectable on demand with acrylic or polyurethane resin and micro-fine cement.
What is it?
A re-injectable PVC injection hose with integral one-way valves that is cast into concrete construction joints. When water ingress is detected, the hose is injected with resin or cement grout to seal the joint from inside.
Where is it used?
Construction (day-work) joints in watertight reinforced-concrete structures: basements, water-retaining tanks, tunnels, metro boxes, STPs/WTPs, lift pits, raft-to-wall and wall-to-wall kickers.
Why use it?
It converts a construction joint into a serviceable, re-sealable joint. If a leak appears now or years later, the joint can be injected (and re-injected) without breaking out concrete or excavating.
How is it applied?
The hose is clipped to the rebar/substrate along the joint centreline before the second concrete pour, with injection and vent ends brought out to accessible packers/boxes. After concrete matures, a pump injects grout through the valves to seal.
About Fosroc Supercast Injectoseal
Fosroc Supercast Injectoseal is a re-injectable injection-hose waterstop system, part of Fosroc’s Supercast range of construction-joint sealing and waterproofing products. It is fundamentally different from a gun-grade or pouring-grade joint sealant: rather than filling a visible surface joint, Injectoseal is a small-diameter PVC hose fitted with integral “valve” perforations that is embedded along the centreline of a concrete construction joint during casting. The hose stays dormant inside the hardened concrete. If the joint ever seeps, an applicator connects a resin pump to the hose ends and forces injection grout out through the valves and into the joint, sealing the leak path under pressure. Because the valves reseal, the same circuit can be re-injected later if required. Injectoseal is designed for the day-work (construction) joints of below-ground and water-retaining structures, where a poured-in waterstop alone offers no second chance once concrete has set. It accepts a range of Fosroc injection media — low-viscosity acrylic (acrylate) resins, polyurethane resins and micro-fine cement suspensions — letting the applicator match the grout to the leak (fine cracks vs. flowing water vs. permanent flexible seal). The system is rated by Fosroc against water pressures up to 10 bar, equivalent to roughly a 100 m head, making it suitable for deep basements, reservoirs and tunnel structures. For Indian projects, Space Arc Engineering supplies Injectoseal alongside the wider Supercast PVC and swellable-waterstop range and the associated acrylic/PU injection resins, with applicator support across Delhi NCR and Pan-India. Installation, injection material selection and re-injection are intended to be carried out by a Fosroc-approved applicator.
The technical insight
The performance of an injection-hose system lives or dies on three things: valve geometry, circuit length, and timing. Injectoseal works on a one-way-valve principle — grout pumped into the hose is forced out through slit/valve openings into the joint, but the openings resist concrete paste pushing in during the pour (which would clog the hose). To keep injection pressure usable along the whole run, circuits are kept short; long joints are split into multiple discrete circuits with injection and vent ends terminated at accessible packer boxes rather than run as one continuous loop. The companion Supercast Predimax injection hose in the same family is built as a double-walled PVC hose (11 mm external / 6 mm internal diameter) with the inner hose slotted every 20 mm on alternating 90° faces — the geometry that allows omnidirectional grout exit while staying re-injectable. Critically, injection must wait until the concrete has matured (the related Fosroc guidance specifies a minimum of 28 days) so the structure can take injection pressure and the grout can key into a stable joint. The choice of injection medium is an engineering decision: micro-fine cement suspensions suit hairline construction-joint seepage and give a rigid mineral seal; acrylate resins are ultra-low-viscosity for tight paths and give a flexible/elastic seal that tolerates slight movement and re-wetting; polyurethane resins foam on contact with water and are favoured for actively flowing leaks. Hose placement matters too — on thick walls (>600 mm) the hose is set toward the water side (around 250 mm from the water face) so the seal forms where the head acts, not in the middle of the section.
Where it is used
- Horizontal construction (kicker) joints between raft/base slab and walls in basements and water tanks
- Vertical and horizontal day-work joints in water-retaining structures — RCC overhead and underground reservoirs, ETPs/STPs, clarifiers
- Tunnel, cut-and-cover and metro box construction joints subject to high groundwater head
- Lift pits, sump pits and deep basement rafts where post-construction leak access is impossible
- Diaphragm-wall and secant-pile capping-beam to slab interfaces
- Repair/remedial sealing of new construction joints as a planned re-injectable backup to a cast-in PVC or swellable waterstop
- Pile-cap to raft and column-stub junctions in below-ground structures
- Joints in saline, sewage or chemically aggressive groundwater environments where a re-sealable system is preferred
Key advantages
- Re-injectable — the joint can be sealed again years later through the same hose circuit, without breaking out concrete or excavating
- Integral one-way valves let grout exit omnidirectionally while resisting concrete paste ingress during the pour
- Accepts multiple injection media (acrylic/acrylate resin, polyurethane resin, micro-fine cement) so the grout can be matched to the leak type
- Rated against water pressure up to 10 bar (approx. 100 m head) for deep basements, reservoirs and tunnels
- Resistant to continuous immersion in groundwater, saline, sewage, alkalis, acids and hydrocarbons (in the double-walled Predimax hose form)
- Provides a planned, serviceable backup to conventional cast-in waterstops, de-risking critical watertight structures
- Compact hose installs quickly by clipping to rebar before the second pour — minimal disruption to the casting sequence
- Injection and vent ends terminate at accessible boxes, so future sealing is done from the dry/accessible face
Limitations & considerations
- Seals construction joints only — it is not a movement/expansion-joint product and accommodates no designed joint movement
- Effective only if a leak path actually intersects the hose; it does not waterproof the wider concrete section or honeycombing away from the joint
- Requires specialist injection equipment and a Fosroc-approved applicator for installation, injection and re-injection
- Injection should not begin until the concrete has matured (related Fosroc guidance: minimum 28 days), so it is not an instant fix during construction
- If the hose is crushed, kinked, blocked by concrete paste, or its ends are lost/buried, that circuit may become un-injectable
- Circuit length is limited; long joints must be divided into multiple circuits with separate injection/vent points — needs planning at design stage
- Not a substitute for good joint preparation, compaction and a primary waterstop; it is a complementary/standby system
- Performance and re-injectability depend heavily on correct fixing, valve protection and accurate location of injection points
Selection & best practice
Treat Injectoseal as a designed, serviceable system, not an afterthought. Fix the hose to the rebar or substrate along the joint centreline with clips at close, regular intervals so it cannot float or kink during the pour, and on walls thicker than ~600 mm position it toward the water side (around 250 mm from the water face). Keep circuits short — split long joints into discrete runs with overlaps of roughly 100–150 mm between adjacent hoses and bring both the injection and vent ends out to clearly labelled, accessible packer boxes; never bury an end. Protect the valves from concrete paste during casting and check the hose is clear before the pour covers it. Do not inject until the concrete has matured (minimum 28 days per related Fosroc guidance). Select the injection medium to match the leak: micro-fine cement for hairline seepage and a rigid seal, low-viscosity acrylate resin for tight paths and a flexible re-wettable seal, polyurethane resin for actively flowing water. Always engage a Fosroc-approved applicator for installation, injection and any future re-injection, and record circuit locations on as-built drawings so the system can be re-used over the structure’s life.
Specifications
| Product type | Re-injectable injection-hose waterstop with integral ‘valves’ for sealing concrete construction joints |
| Chemistry / hose material | PVC hose (double-walled in the Predimax hose form of the Supercast injection range) |
| Grade | Cast-in injection hose (not a gun-grade or pouring-grade surface sealant) |
| Injection media accepted | Acrylic/acrylate resin, polyurethane resin, micro-fine cement suspensions |
| Re-injectable | Yes — re-injectable with Fosroc resins and micro-fine cement suspensions |
| Water pressure rating | Up to 10 bar (approx. 100 m water head), per Fosroc product data |
| Hose dimensions (Predimax companion hose) | 11 mm external dia. / 6 mm internal dia.; inner hose slotted every 20 mm, rotated 90° |
| Hose placement (thick walls) | Max ~250 mm from the water face on walls wider than 600 mm |
| Hose overlap / spacing | Approx. 100–150 mm overlap between adjacent hoses (typical Fosroc guidance) |
| Minimum concrete age before injection | 28 days (related Fosroc guidance) |
| Suitable joints | Construction / day-work joints in watertight structures |
| Movement accommodation | None — construction-joint system, not a movement/expansion-joint sealant |
| Chemical resistance | Groundwater, saline, sewage, alkalis, acids, petrol, diesel, alcohol (Predimax double-walled hose) |
| Installation / injection | By Fosroc-approved applicator using specialist injection equipment |
| Standard supply length (Predimax companion hose) | 100 m unit (FC070403-UNIT) |
Industry use cases
Metro & Tunnelling
Construction joints in cut-and-cover boxes, station rafts and tunnel segments under high groundwater head are fitted with Injectoseal circuits as a re-injectable backup, so leaks discovered after commissioning can be sealed from inside without excavation.
Water & Wastewater (STP/WTP)
Day-work joints in RCC clarifiers, aeration tanks, reservoirs and ETP/STP structures use Injectoseal because the hose tolerates saline and sewage exposure and the joint can be re-sealed over the asset’s service life.
Commercial & Residential Basements
Deep multi-level basement rafts, lift pits and sump pits in Delhi NCR developments specify Injectoseal at the kicker (raft-to-wall) joints, giving developers a planned remedy for the joints that are otherwise impossible to access once the building is complete.
Industrial & Infrastructure
Diaphragm-wall capping-beam to slab interfaces, pile-cap junctions and water-retaining process structures use Injectoseal as a serviceable complement to cast-in PVC or swellable waterstops on critical leak-sensitive joints.
Frequently asked questions
Is Supercast Injectoseal a joint sealant like Nitoseal or Thioflex?
What can be injected through Injectoseal?
Can the same joint be sealed more than once?
What water pressure can it handle?
How and when is the hose injected?
Does it replace a conventional waterstop?
How we position Fosroc Supercast Injectoseal
Within the Fosroc Supercast family, Injectoseal occupies the “re-injectable construction-joint” niche and should be specified where future access to a leaking joint is impossible — deep rafts, lift pits, tunnels and water-retaining tanks. It is commonly paired with passive waterstops from the same range: Supercast PVC extruded waterstops and the Supercast SW/SWX swellable range provide the primary cast-in seal, while Injectoseal (and its companion Predimax injection hose) provides the serviceable, injectable backup. It is not interchangeable with Fosroc’s elastomeric joint sealants — Nitoseal MS600 (MS-polymer), Thioflex 600 (polysulphide) and Colpor 200PF (cold-applied PU for trafficked/expansion joints) seal accessible moving joints at the surface, whereas Injectoseal seals hidden, non-moving construction joints from within. Credible alternative injection-hose systems engineers may also evaluate include Sika’s injection hose range (e.g. SikaFuko), MBCC/Master Builders Solutions MasterSeal injection hoses, and STP/other proprietary re-injectable hose systems; the deciding factors are valve design, re-injectability, approved-applicator support and compatibility with the chosen resin. As an authorised Fosroc distributor and applicator, Space Arc Engineering supplies Injectoseal with the matching Fosroc acrylic/PU resins and micro-fine cement, plus the full Supercast waterstop range, and provides specification and applicator support across Delhi NCR and Pan-India.
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