About Fosroc Renderoc Plug 5

Fosroc Renderoc Plug 5 is the 5 kilogram retail pack of Fosroc’s Renderoc Plug rapid-setting, cement-based water-stopping mortar. It is the single most reached-for product on Indian sites the moment water starts pouring through a crack, a cold joint or a pipe penetration that nobody planned for. Supplied as a ready-blended dry powder, it requires only the on-site addition of clean water to produce a stiff, fast-setting mortar that can be hand-pressed straight into a leaking chase and held in place until it grips. Where conventional repair mortars would simply wash out, Renderoc Plug develops enough early strength within about a minute to resist the flow and physically plug the leak.

The product is built around a controlled blend of cement, graded aggregates, special fillers and chemical accelerators. The accelerator package is what gives Renderoc Plug its signature near-instant set, while the formulation is engineered to keep the heat of reaction (exotherm) low so that the rapid hydration does not cause thermal cracking inside the patch. It is chloride-free, which matters in India where it is routinely used near reinforcement in RCC basements, water-retaining structures and marine-influenced coastal construction. Fosroc’s full Renderoc Plug range actually offers two set-speed grades – a roughly one-minute grade for live, running-water emergencies and a roughly twenty-minute grade for larger patch repairs and potable-water work. The 5 kg “Plug 5” pack sold across Delhi NCR and pan-India is the fast, one-minute leak-plugging grade, sized for handymen, maintenance crews and small contractors who need a single convenient bag rather than a bulk sack.

For Space Arc Engineering’s customers – waterproofing applicators, RMC and infrastructure contractors, plumbing and facility-maintenance teams – Renderoc Plug 5 sits at the front line of the waterproofing toolkit. It is rarely the final waterproofing layer; instead it buys the time and the dry substrate needed to then apply a proper membrane, a crystalline slurry or a polyurethane injection system. As an authorised Fosroc distributor, Space Arc supplies genuine, in-date stock with correct batch traceability, which is important for a product whose performance depends entirely on its accelerator chemistry staying fresh.

The technical insight

The performance of Renderoc Plug comes from a deliberately stiff, low water-to-powder mix (1 part water to 3 parts powder by volume) combined with a flash-set accelerator system. Because the mortar is mixed dry-ish and packed by hand, hydration begins almost immediately and the mass goes from plastic to load-bearing within about a minute at 20 degrees C. This is why you must mix only what you can place in seconds – there is no realistic working time once water hits the powder. The chemistry is temperature-sensitive in both directions: in cold conditions down to 1 degree C, warm mixing water (up to 20 degrees C) is advised to keep strength developing, while above 35 degrees C – common across most of India for much of the year – the bags should be stored in shade and cooler water used, because heat shortens the already brief set window. Tested at 1:3 by volume and 20 degrees C, the fast grade reaches about 10 MPa compressive strength at 1 hour and 1 day, climbing to roughly 23 MPa at 28 days, with pull-off bond around 0.8 MPa and chloride ion content about 0.01 percent. The mortar conforms to BS EN 1504-3 Class R1 (a structural/non-structural concrete repair classification) and carries a Class A1 non-combustible fire rating. The critical site discipline is substrate prep: the leak point must be cut back to at least 15 mm depth and undercut to a roughly 20 mm square chase so the plug keys mechanically and cannot be pushed out by water pressure – feather-edges and v-grooves will fail.

Where it is used

• Plugging active, running-water leaks in basement walls, retaining walls and lift pits
• Sealing leaking construction joints and cold joints in RCC water tanks and STPs
• Stopping seepage at pipe penetrations, conduit entries and tie-rod / form-tie holes
• Emergency leak arrest in sewers, manholes, below-ground access chambers and inspection pits
• Rapid patching of precast concrete segments and brick / concrete tunnel and shaft linings
• Holding back water ingress in basements and foundations ahead of a permanent waterproofing system
• Quick repairs in mines, culverts, pump houses and underground service galleries

Key advantages

• Stops live, running water in approximately one minute – true emergency water-stopping capability
• Single component – only clean water needs to be added on site, no second pack to gauge
• Pre-bagged blend overcomes inconsistent site batching and gives repeatable results
• Excellent mechanical bond to a sound, saturated-surface-dry concrete or masonry substrate
• Low exotherm formulation minimises the thermal cracking that fast-setting mortars can suffer
• Chloride-free, so it is safe to use adjacent to embedded steel reinforcement
• Conforms to BS EN 1504-3 Class R1 and is rated Class A1 non-combustible
• Convenient 5 kg pack size ideal for maintenance crews, plumbers and small repair jobs
• No primer required, and it can be applied to horizontal, vertical and overhead surfaces

Limitations & considerations

• Extremely short working time – mortar must be placed within seconds, so only tiny batches can be mixed at once
• Not a standalone waterproofing system; it plugs the leak but a membrane, crystalline or injection system is still needed for durable protection
• Minimum application thickness is 15 mm – it cannot be used as a thin skim or feather-edge
• Set speed swings sharply with temperature; above 35 degrees C the window shrinks further, demanding shaded storage and cool water
• Substrate must be cut back and undercut properly – poor chasing leads to blow-outs under water pressure
• Relatively high cost per kg (around Rs 380/kg in India) versus ordinary repair mortars, so it is reserved for leak points, not bulk filling
• Short practical shelf life – the accelerator loses potency in humid or hot storage, so fresh, in-date stock is essential
• The 5 kg fast grade is not the WRAS / potable-water approved grade; the 20-minute Renderoc Plug 20 grade is the one approved for public water supplies

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Renderoc Plug 5

Renderoc Plug 5 is Fosroc’s first-response leak-stopper and pairs naturally with the rest of the Fosroc waterproofing range: use it to arrest the leak, then finish with a Fosroc crystalline or membrane system (e.g. the Brushbond / Nitoproof families) or a Fosroc polyurethane / acrylic injection resin for the permanent seal. Within the wider Indian market it competes directly with Sika Plug and Sika-101a, MBS plugging compounds, Dr. Fixit Pidiproof LW+/quick-plug products, and STP (Shalimar) quick-setting plug mortars. Renderoc Plug’s edge is its very fast, chloride-free, EN 1504-3 Class R1 set with low exotherm and a globally consistent pre-bagged formulation; rivals such as Dr. Fixit and Sika are often more widely stocked at retail and may be cheaper per kg, so the choice usually comes down to availability, the severity of the leak, and whether the rest of the waterproofing build-up is on a Fosroc, Sika or Dr. Fixit system. For potable-water tanks, specify the slower WRAS-approved Renderoc Plug 20 grade rather than the fast 5 kg pack.

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