MC-Bauchemie MC-Nafuplan WPS
A hand-applied hydraulic compound that sets in under two minutes to arrest live, pressurised water leaks in concrete and masonry, with no injection rig required.
What is it?
A single-component, factory-blended hydraulic plugging compound (rapid-hardening cements, reactive mineral fillers and accelerators) that you mix by hand and press into a leaking chase or void.
Where is it used?
Basement walls, water tanks, tunnel and shaft linings, construction joints, pipe penetrations and any spot where water is actively pushing through concrete or brickwork.
Why use it?
It sets against running water in 30 to 90 seconds and expands slightly as it hardens, sealing the leak on the spot without draining or drying the structure first.
How is it applied?
Cut a minimum 20 mm chase, mix the powder to a stiff dough, form a ball, and hand-press it into the leak point, holding firm pressure until it grabs and sets.
About MC-Bauchemie MC-Nafuplan WPS
MC-Nafuplan WPS is MC-Bauchemie’s answer to one of the most stubborn problems on a waterproofing job: a leak that is already live. Most repair mortars need a dry, prepared surface, which is impossible when water is streaming out of a basement wall or a tank joint. This compound is built for exactly that moment. It is a single-component powder, factory pre-blended so there is nothing to weigh out or dose on site, combining rapid-hardening cements with reactive mineral fillers and chemical accelerators. Add a small, controlled amount of clean water, knead it by hand into a stiff putty, and it is ready to go straight against the flow.
What makes it practical for Indian sites is that it needs no specialist equipment. Where a crack or joint under pressure would normally call for a two-part injection resin and a pump, a point leak or a weeping construction joint can often be closed by a single trained applicator with a bucket of WPS and a trowel. It sets in seconds, reaches roughly 15 MPa within a day and around 25 MPa at 28 days, and holds back water pressure of up to about 3 bar (near 30 metres of head) when the plug is properly keyed into sound substrate. For contractors dealing with emergency ingress, that combination of speed, strength and zero-kit simplicity is the whole point.
The technical insight
The compound works on two mechanisms happening at once. First, its rapid-hardening cement chemistry hydrates and sets in 30 to 90 seconds at around 25 degrees Celsius, far faster than ordinary Portland systems, so the plug develops grab strength before the water can wash it out. Second, as it hydrates it generates a mild expansive force, so the material pushes outward against the walls of the chase rather than shrinking away from them. That expansion is what turns a lump of mortar into a watertight wedge: it locks mechanically into the undercut profile you have cut, and the tighter fit resists the water pressure trying to force it back out. Because the reaction is self-accelerating, the working window is short, and you control it with water content. Slightly less water gives you a faster, stiffer set for a high-pressure leak; a touch more buys a few extra seconds to position the plug. This is why a mechanical key and firm, sustained hand pressure during that first 30 to 60 seconds matter so much. Get the substrate profile and the hold right, and the plug seals permanently against the very pressure that caused the leak.
Where it is used
- Stopping active leaks in basement and retaining walls under water pressure
- Sealing weeping or running construction joints during and after casting
- Plugging water ingress in tunnel and shaft linings before final waterproofing
- Emergency repair of leaks in water tanks, reservoirs and treatment structures
- Sealing around pipe penetrations and service entries where water is tracking through
- Arresting spot leaks in lift pits, sumps and below-ground chambers
- Pre-sealing live leaks so a membrane or coating system can be applied over a dry surface
- Quick patch repairs to leaking masonry and brickwork in older structures
Key advantages
- Sets in 30 to 90 seconds, fast enough to plug a live, running leak on the first attempt
- Needs no injection pump, packers or specialist rig, so a single applicator can do the job
- Single-component powder, factory pre-blended, only clean water added on site
- Slight expansion as it cures locks the plug into the chase and resists back-pressure
- Reaches roughly 15 MPa in 24 hours and around 25 MPa at 28 days for a durable seal
- Holds water pressure up to about 3 bar (near 30 m head) when correctly keyed in
- Applied straight onto wet, actively leaking substrate with no need to dry the surface
- Set speed is tunable through water content to match the severity of the leak
Limitations & considerations
- Working time is only 30 to 90 seconds, so it must be mixed in small batches and placed immediately
- Not a substitute for injection grouting on deep cracks or joints that need resin behind the face
- Requires a proper mechanical key or undercut chase; smeared over a flat wet surface it will not hold
- Demands continuous, firm hand pressure through the initial set, which is physically hands-on work
- Set speed shifts with temperature, so behaviour on a cold winter morning differs from a hot afternoon
- It seals the point of leak but does not, on its own, waterproof the wider structure; a full system is still needed
Selection & best practice
Start by locating the exact point of ingress and cutting a chase around it, at least 20 to 25 mm deep and about 20 mm wide, with an undercut or dovetail profile so the plug has something to grip. Remove all loose and unsound material but do not attempt to dry the substrate; active water is fine and expected. Mix only as much powder as you can place in one go, adding clean water in small amounts to reach a stiff, cohesive dough, then quickly form it into a ball or cone shaped to the chase. Press it firmly into the leak point and hold with steady hand or trowel pressure for the full 30 to 60 seconds until it sets and grabs. For a high-pressure leak, keep the mix on the drier, stiffer side for a faster set; ease the water up slightly if you need a moment more to position it. Work outward from the strongest flow, plugging the main leak first and dressing the surrounding area afterward. Once the plugs have set and the structure is dry, overcoat the repaired zone with the appropriate MC-Bauchemie waterproofing membrane or coating to protect the whole area, not just the plugged points.
Specifications
| Type | Single-component hydraulic waterproof plugging compound (powder) |
| Composition | Rapid-hardening cements, reactive mineral fillers, chemical accelerators |
| Working / setting time | 30 to 90 seconds at 25 C, adjustable via water content |
| Compressive strength (24 h) | Minimum ~15 MPa |
| Compressive strength (28 d) | Minimum ~25 MPa |
| Water pressure resistance | Up to approx. 3 bar (about 30 m water head), correctly applied |
| Set mechanism | Hydraulic set with mild expansive force |
| Minimum chase profile | 20 to 25 mm depth and about 20 mm width, undercut/keyed |
| Application | Hand-mixed to stiff dough, hand-pressed and held to set |
Industry use cases
Basements & Retaining Walls
Closing live leaks at cracks, tie-holes and construction joints in below-ground walls before applying the main waterproofing system.
Water Retaining Structures
Emergency sealing of weeping joints and spot leaks in tanks, reservoirs and treatment plant structures to arrest loss and restore service.
Tunnels & Underground Works
Stopping ingress through segment joints and linings in tunnels, shafts and mines where injection access is limited or slow.
Infrastructure & MEP
Sealing around pipe penetrations, service entries and lift-pit leaks where water is actively tracking through the concrete.
Repair & Rehabilitation
Reviving leaking older masonry, brick chambers and sumps as a fast first step in a broader waterproofing refurbishment.
Frequently asked questions
Can MC-Nafuplan WPS really be applied while water is still leaking?
How much water pressure can the plug hold?
Do I need an injection pump or any special equipment?
Why does it set so fast, and can I slow it down?
Is plugging the leak enough on its own?
How is it different from an injection grout like MC-Injekt?
How we position MC-Bauchemie MC-Nafuplan WPS
MC-Nafuplan WPS is the front-line plug in a wider MC-Bauchemie waterproofing programme. Use it to arrest the active leak, then move to the right follow-on product: for deep cracks or joints that need filling behind the face, injection resins in the MC-Injekt family are the correct tool, since a hand-pressed plug cannot reach that far. Once the structure is dry, protect the whole area with an MC-Bauchemie membrane or cementitious coating rather than relying on the plugs alone. Where a project specifies a particular brand family, Space Arc also supplies equivalent rapid-set plugging mortars from Fosroc, and crystalline and injection systems from other brands we carry, so the specification can be matched without compromising on speed or performance.
Fosroc Renderoc Plug — A specifier standardising on Fosroc, or needing a choice of set speeds (roughly 1-minute and 20-minute grades), may prefer Renderoc Plug for the same emergency water-stopping duty.
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