About Fosroc Supercast Predimax Injection hose

Fosroc Supercast Predimax Injection Hose is a re-injectable joint-sealing system built around a double-walled, patented (European and American patents) PVC hose. The hose is designed to be permanently cast into a concrete construction joint, cold joint or junction. The principle is simple but powerful: rather than relying on a single static barrier like a PVC or bentonite waterstop, the hose sits inside the joint as an accessible channel. If groundwater later finds a path through that joint, an injection material is pumped down the hose under pressure; it weeps out through controlled slots, fills the surrounding voids and cracks, and cures into a permanent seal that follows the exact route the water was taking.

The double-wall construction is the key to how it works. The inner hose carries the injection material; the outer hose has discharge slots spaced every 20 mm and rotated 90 degrees around the circumference. The slot openings of the inner and outer walls are deliberately staggered so that wet concrete and cement paste cannot enter and block the hose during the pour, yet the slots open freely under injection pressure to release resin or grout into the joint. The PVC formulation is robust and is rated for continuous immersion in groundwater, saline water, sewage, alkalis, acids, petrol, diesel and alcohol — which is why it suits aggressive below-ground and effluent environments.

For Space Arc’s clients across Delhi NCR and Pan-India, the appeal is practical. Indian basement, metro and water-retaining works are routinely cast in multiple lifts, and the construction joint between lifts is the single most common leakage source. Predimax lets the contractor build in a second line of defence at that exact line, then prove the joint is watertight before backfilling or applying the tanking membrane — and keep the option to re-inject open for the life of the structure. The system is supplied as a kit: a suitable length of hose plus colour-coded (white/red) inlet and outlet vents that bring the hose ends out to accessible junction boxes for connection to the injection pump.

The technical insight

The engineering value sits in the staggered double-wall geometry. A naive single-wall slotted hose either clogs with cement paste during concreting or cannot hold injection pressure. Predimax solves both: the inner injection bore and the outer discharge slots (at 20 mm pitch, rotated 90 degrees) are offset so the concrete-side openings are shielded during the pour, then act as one-way-feeling pressure relief points during injection. Material choice matters too — because the PVC resists acids, alkalis, hydrocarbons and sewage, the hose stays serviceable in exactly the environments (STPs, fuel-station slabs, contaminated-ground basements) where ordinary waterstops degrade. Crucially, the system is injection-material agnostic within Fosroc’s range: low-viscosity polyurethanes (Nitofill UR63, Nitofill WS60) for flexible water-reactive sealing of damp/moving joints, epoxy (Nitofill LV) where structural re-bonding of the joint is wanted, and cement suspensions (Nitofill CEM) or polyacrylate gels for larger voids — so the same cast-in hose can be matched to the actual leak behaviour observed on site.

Where it is used

• Horizontal construction joints between basement raft slabs and the wall kicker
• Vertical and horizontal construction/cold joints in retaining and basement walls cast in lifts
• Pile head / pile cap to raft junctions where leakage paths are common
• Lift pits, ramps and other below-ground boxes requiring serviceable joint sealing
• Water-retaining structures: RCC water tanks, reservoirs, canals and treatment-plant tanks
• Sewage treatment plant (STP) and effluent structures exposed to aggressive chemistry
• Tunnels, subways, metro box sections and cut-and-cover segments at segment/lift joints
• Repair scenario: sealing a known leaking construction joint by re-injection without chasing the concrete

Key advantages

• Re-injectable — the joint can be sealed after striking formwork and, if needed, re-sealed years later without drilling or breaking out concrete
• Double-wall, staggered-slot design prevents cement paste blocking the hose during the pour while still releasing injection material cleanly
• Non-destructive: no core drilling or structural damage required to seal a leaking joint
• PVC fully resistant to continuous immersion in groundwater, saline, sewage, acids, alkalis, petrol, diesel and alcohol — suits aggressive Indian below-ground and effluent sites
• Compatible with a range of Fosroc injection materials (PU, epoxy, cement, polyacrylate), so the seal can be tuned to the leak
• Allows pre-membrane verification — the joint’s water-tightness can be proven before tanking or backfill
• Colour-coded white/red inlet and outlet vents make injection points easy to identify on a busy site
• Works under both high and low injection pressure

Limitations & considerations

• It is a joint-line product only — it seals the construction/cold joint it is cast into, not random through-slab cracks away from the hose run
• Performance depends entirely on correct installation: the hose must sit on the joint centreline, be continuously clipped, and have both ends brought out to accessible vents/junction boxes
• Each hose run has a practical maximum injection length, so long joints must be split into sections each with its own inlet and outlet — poor sectioning leaves portions un-injectable
• Once injected with a curing resin, that section is consumed; only systems left as single-use must be planned with re-injection in mind
• Requires an injection pump and a trained applicator plus the correct Nitofill injection resin/grout — it is not a stand-alone DIY item
• Cannot rescue a joint where the vents were damaged, buried or lost during concreting — vent accessibility is non-negotiable
• It supplements, rather than replaces, good joint preparation and concrete compaction

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Supercast Predimax Injection hose

Supercast Predimax sits in Fosroc’s joint-sealing/waterstop family and is best understood as the re-injectable upgrade to a static waterstop. On a critical basement or water-retaining joint, it pairs naturally with Fosroc’s Supercast PVC waterstops or Supercast SW swellable strips (the static barrier) plus Nitofill UR63/WS60, Nitofill LV or Nitofill CEM as the injection material — and it complements membrane tanking such as Proofex. Within the wider Indian market, the closest comparable injection-hose systems are Sika’s SikaFuko / Sika Injectoflex range, the BASF/MBCC (now MBS/Master Builders Solutions) MasterSeal injection hose systems, and STP Ltd’s joint-injection offerings; Dr. Fixit (Pidilite) competes mainly on crack-injection resins and waterstops rather than a like-for-like cast-in re-injectable hose. The honest positioning: choose Predimax when the joint must remain serviceable and re-sealable and you want a single Fosroc-compatible chain from hose to injection resin; choose a competitor where it is already specified, locally stocked, or bundled with that brand’s injection pump and resin. The hose alone does not waterproof a structure — it is one engineered layer in a joint-sealing strategy.

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