Fosroc Renderoc Plug
A single-component, rapid-setting cement mortar that plugs actively running water leaks in about a minute — the go-to first response before permanent waterproofing.
What is it?
A pre-bagged, chloride-free hydraulic cement mortar (Fosroc’s Renderoc Plug range) that hardens fast enough to stop water that is still flowing. It ships in two grades: Renderoc Plug 1 for live leaks and Renderoc Plug 20 where a longer working window is needed.
Where is it used?
Basements, retaining walls, lift pits, water tanks, tunnels, culverts, sewers, below-ground chambers and any structure where groundwater or seepage is entering through a joint, crack or tie-rod hole.
Why use it?
It buys you control. Instead of fighting a live jet of water with ordinary mortar that simply washes away, Renderoc Plug sets hard against the flow, letting the crew dry the area and apply a proper waterproofing system afterwards.
How is it applied?
Mixed one part clean water to three parts powder by volume into a stiff dough, then trowelled or hand-kneaded into the chased-out leak and held in place until it sets — no primer, minimum 15 mm thickness.
About Fosroc Renderoc Plug
On many Indian sites, the name “Plugtite” gets used loosely for Fosroc’s fast-setting leak-plugging mortar. The genuine product behind that description is Fosroc Renderoc Plug, and that is what we supply and what this page covers. It is a single-component, ready-to-use blend of cement, graded aggregates, special fillers and set-controlling additives — you add nothing but clean water on site. The formulation is deliberately built to hydrate and stiffen within seconds to minutes rather than hours, which is exactly what a crew needs when water is pushing through a construction joint faster than any conventional patch could hold.
Renderoc Plug comes in two grades that share the same chemistry but differ in working time. Renderoc Plug 1 reaches initial set in roughly one minute at 20°C and is the grade you reach for when the leak is live and moving. Renderoc Plug 20 sets in about twenty minutes, giving a workable window for larger patch repairs and for potable-water situations where it carries WRAS / BS 6920 approval. Both grades comply with BS EN 1504-3 as a Class R1 repair mortar, contain no chloride, and are non-combustible (Class A1). In practice it is a specialist product with a narrow, honest job: arrest the water so the real waterproofing work can begin.
The technical insight
The reason ordinary repair mortar fails against a live leak is simple — the mix water is displaced by the incoming water before the cement can knit together, so the patch dilutes and sloughs off. Renderoc Plug is engineered around a very short induction period: its set-accelerating additives drive rapid early hydration so the mortar gains enough green strength to physically resist the flow while it is still being held by hand. Renderoc Plug 1 develops roughly 10 MPa compressive strength within an hour of placing and reaches about 23 MPa at 28 days, while the slower Renderoc Plug 20 builds to around 45 MPa at 28 days. Crucially, the fillers keep the exotherm low, so this speed does not come at the cost of thermal cracking. Bond to a sound, saturated-surface-dry substrate is strong (0.8 MPa pull-off for Plug 1, 1.1 MPa for Plug 20), and because the chase is cut square and undercut rather than V-shaped, the set plug keys mechanically into the concrete instead of being pushed straight back out. It seals the water; it is not, by itself, the finished waterproofing system.
Where it is used
- Stopping active groundwater seepage through basement and retaining-wall construction joints
- Plugging tie-rod and form-tie holes that weep after formwork is struck
- First-response sealing of live leaks in lift pits, water tanks and swimming pools during dewatered repair
- Rapid patching of concrete and brick tunnel linings and segments
- Sealing water ingress in sewers, culverts and below-ground access chambers
- Emergency plugging of leaks around pipe penetrations and service entries
- Chasing and sealing running cracks before applying a crystalline or coating waterproofing system
- Potable-water tank and reservoir repairs using the WRAS-approved Renderoc Plug 20 grade
Key advantages
- Sets in about one minute (Plug 1) or twenty minutes (Plug 20) at 20°C, so you can match working time to the job
- Actually holds against flowing water where conventional mortars wash out
- Single component — only clean water is added, removing site batching error
- Chloride-free (0.01% chloride ion), so it is safe against embedded reinforcement
- Complies with BS EN 1504-3 Class R1 and is Class A1 non-combustible
- Low exotherm keeps thermal cracking risk down despite the rapid set
- No primer needed — applied straight onto a saturated surface-dry substrate
- Renderoc Plug 20 is WRAS / BS 6920 approved for contact with potable water
Limitations & considerations
- It stops the leak but is not a standalone waterproofing system — a proper membrane, coating or crystalline treatment must follow
- Very short pot life on Plug 1 means only tiny batches can be mixed, hand-placed and held one leak at a time
- Minimum application thickness is 15 mm and feather-edges are not permitted, so it is unsuitable for thin skim repairs
- Set and cure times shift with temperature — noticeably slower below a few degrees and faster above 35°C
- Substrate must be cut back and chased square/undercut; it will not bond reliably to loose, oily or laitance-covered surfaces
- Plug 20 patch repairs are limited to about 0.06 m² per bay and 0.25 m linear sections
Selection & best practice
Cut the leak back to a chase roughly 20 mm square and always undercut it so the plug keys in rather than sitting in a V that water can push out; areas being patched should be cut to at least 15 mm depth and mechanically keyed, never feather-edged. Brush the substrate clean of dust, laitance and loose material, and steam-clean or jet off any grease or slime. Mix one part clean water to three parts powder by volume to a stiff dough, and only ever gauge as much as one person can place within the set time — for Plug 1 that means a single leak at a time. Press or hand-knead the mortar firmly into the opening and hold it in place until initial set is reached against the flow. Use Plug 1 for genuinely running water; switch to Plug 20 where you need working time or potable-water approval. In cold conditions (down to 1°C) use warm water up to 20°C to help strength gain; above 35°C store the material in shade and mix with cooler water. Once the leak is arrested, complete the repair with the appropriate Fosroc waterproofing or repair system.
Specifications
| Product type | Rapid-setting, single-component cement-based leak-plugging mortar |
| Grades | Renderoc Plug 1 (fast) and Renderoc Plug 20 (extended set) |
| Initial set at 20°C | Approx. 1 minute (Plug 1); approx. 20 minutes (Plug 20) |
| Compressive strength (Plug 1) | ~10 MPa @ 1 hour; ~23 MPa @ 28 days (EN 12190) |
| Compressive strength (Plug 20) | ~7 MPa @ 6 hours; ~45 MPa @ 28 days (EN 12190) |
| Bond strength (pull-off, EN 1542) | 0.8 MPa (Plug 1); 1.1 MPa (Plug 20) @ 28 days |
| Chloride ion content | 0.01% (well under the 0.05% limit) |
| Standard / fire rating | BS EN 1504-3 Class R1; Class A1 non-combustible |
| Mix ratio, thickness & pack | 1 part water : 3 parts powder by volume; min 15 mm; Plug 1 6 kg bag yields 3 L, Plug 20 25 kg bag yields 12.5 L; 12-month shelf life |
Industry use cases
Basements & Podiums
Arresting live groundwater seepage through wall-slab joints and tie-rod holes before the tanking or crystalline system goes on.
Water Retaining Structures
Plugging leaks in dewatered tanks, reservoirs and swimming pools — Plug 20’s WRAS approval suits potable-water repairs.
Tunnels & Infrastructure
Rapid first-response sealing of water ingress in tunnel linings, culverts and segment joints on metro and highway works.
Sewerage & Utilities
Stopping infiltration in below-ground chambers, manholes, sewers and around pipe penetrations.
Industrial & Foundations
Emergency leak control in lift pits, machine foundations and plant basements where standing water is holding up other trades.
Frequently asked questions
Is there really a Fosroc product called Plugtite?
Will it stop water that is actively flowing?
What is the difference between Renderoc Plug 1 and Plug 20?
Do I still need a waterproofing system after using it?
How much do I need and how do I mix it?
Is it safe near steel reinforcement?
Can I use it in cold or very hot weather?
How we position Fosroc Renderoc Plug
Renderoc Plug is a specialist leak-stopper, not a general repair mortar — it belongs at the start of a repair sequence, and we position it alongside the products that complete the job. Once the water is stopped, most Indian basement and tank repairs move on to a permanent barrier: Fosroc Brushbond (flexible cementitious coating), Fosroc Nitobond crystalline or the Nitocote membrane range for the waterproofing, and Renderoc GP or Renderoc HB for structural reprofiling of the concrete around the repair. For live joints that keep moving, a hydrophilic swellable strip such as Fosroc Hydrotite or a Fosroc PU/hybrid joint sealant is the durable partner rather than more plug mortar. Where a client is standardised on another brand, we can match the same sequence with Sika (Sika-4a rapid plug plus SikaTop / Sikalastic systems), Dr. Fixit (LW+ and the leak-stop range) or MC-Bauchemie. Our role as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India is to specify the whole chain honestly, so you are not left with a plugged leak and no waterproofing behind it.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.