Fosroc Polyurea WH100
Fast-setting, hand-applied two-component hybrid polyurea coating that delivers a seamless, high-elongation waterproof membrane for roofs, podiums and decks, without spray plural-component equipment.
What is it?
A two-component (Part A ISO + Part B Amine), hand-applied, rapid-curing aromatic hybrid polyurea that cures to a seamless, flexible, high-elongation waterproof and protective membrane.
Where is it used?
Exposed and protected roofs, podium decks, stadium stands, green roofs and planter boxes, service roofs, balconies and terraces over concrete and steel substrates.
Why use it?
It gives spray-grade polyurea performance (>400% elongation, seamless, abrasion-resistant) but is brush/roller/squeegee applied, so it suits smaller areas, detailing and sites where plural-component spray rigs cannot reach.
How is it applied?
Prime the prepared substrate (Nitoprime 31 on dry concrete/steel, Fosroc Primer 195 on damp concrete), blend Part A and Part B (A100:B6 by weight), apply by roller, brush, trowel or squeegee to ~1.5 mm DFT, then spike-roll to release entrapped air.
About Fosroc Polyurea WH100
Fosroc Polyurea WH100 is a hand-applied, two-component, rapid-curing hybrid polyurea system engineered as a combined waterproofing and protective coating for concrete and steel. It is supplied as Part A ISO (an isocyanate component) and Part B Amine, which are blended on site and laid down as a cold-applied liquid that cures into a seamless, monolithic elastomeric membrane. Unlike conventional pure-polyurea systems that demand heated, high-pressure plural-component spray machines and trained spray operators, WH100 is formulated to be applied by roller, brush, trowel or squeegee. That single design choice is what makes it relevant for a large share of Indian projects, where access, power, and skilled spray crews are often the real constraints rather than the coating chemistry itself.\n\nFor a distributor audience in Delhi NCR and across India, WH100 sits in a useful gap. Acrylic and PU liquid membranes are easy to apply but offer limited mechanical toughness and shorter service life. True sprayed polyurea is extremely tough and fast but is capital-intensive and impractical for terraces, planter boxes, intricate detailing, and remote service roofs. WH100 carries genuine polyurea-family properties, over 400% elongation, 6 MPa tensile strength and strong abrasion and puncture resistance, into a format a normal applicator crew can lay by hand. The cured film is seamless with no laps or welds, which removes the most common failure point of sheet membranes, namely the joints. The product has independently verified physical properties (tested after a minimum 14-day cure) and, as a roof waterproofing system, carries a British Board of Agrément certificate (23/7075), giving specifiers third-party assurance that is uncommon in this category in the Indian market.\n\nA point of honesty buyers should understand up front: WH100 is an aromatic polyurea. Like all aromatics, it will undergo significant colour change (chalking/yellowing) on prolonged UV exposure. Fosroc is explicit that this is cosmetic and does not degrade the physical or waterproofing performance of the membrane. Where a stable colour, a defined Solar Reflectance Index, or a formal fire rating is required for an exposed roof, the membrane is overcoated with Fosroc Nitoproof UVR Topcoat, which then delivers colour stability, an SRI of 102 (ASTM E1980, white) and a BS 476-3 EXT F.AA fire rating. Space Arc Engineering supplies WH100 together with its full primer and topcoat ecosystem so the system is specified and delivered as designed rather than as a single tin.
The technical insight
The defining feature is the hand-applied hybrid chemistry. Pure polyurea reacts in seconds and must be plural-sprayed; WH100 is reformulated as a hybrid with a usable pot life of 1 hour at 23°C and a fixed mix ratio of A100:B6 by weight (A100:B8 by volume), so a two-person crew can mix in a bucket and lay it by hand. The trade-off versus sprayed polyurea is application thickness and rate, not membrane quality. The normal dry film thickness is 1.5 mm in a hand-applied build, and the spike-roller pass after application is technically critical: it releases entrapped air introduced during hand mixing and laydown, preventing pinholes and surface bubbling that would otherwise create weak points. Cure is staged, the film can be carefully walked on after about 2 hours, takes light foot traffic after roughly 24 hours, and is fully serviceable in 2-3 days, all temperature-dependent. The other non-negotiable is the primer-substrate gate: concrete must have reached at least 75% of design strength with relative humidity ≤75%, surface temperature must be at least 5°C and 3°C above dew point, and application is barred if ambient RH exceeds 85%. These windows are tighter than for forgiving acrylic membranes and are the usual root cause of field underperformance when ignored.
Where it is used
- Waterproofing of exposed and protected flat roofs over RCC slabs
- Podium decks and landscaped deck waterproofing above occupied space
- Stadium stands and spectator terraces
- Green roofs and planter boxes (membrane fully cured before soil is added)
- Service roofs and plant rooms with restricted access for spray equipment
- Balconies, terraces and chajjas requiring seamless detailing
- Protective coating of steel structures against corrosion and abrasion
- Smaller or congested roof areas where plural-component spray rigs are impractical
Key advantages
- Hand-applied by roller, brush, trowel or squeegee, no plural-component spray equipment, power or specialist spray crew required
- Seamless, monolithic membrane with no laps, welds or joints to fail, including at detailing
- High elongation (>400%) and 2 mm crack-bridging (ASTM C836) accommodate substrate movement and shrinkage cracks
- Strong mechanical toughness, 6 MPa tensile, 28 N/mm tear and 550 N puncture resistance for trafficked and loaded decks
- Rapid, staged cure, walkable in about 2 hours and serviceable in 2-3 days for fast project turnaround
- Wide service temperature range of -20°C to +80°C suits Indian roof-surface extremes
- Third-party assurance via BBA certificate 23/7075 and independently verified test data
- System can be upgraded with Nitoproof UVR Topcoat for colour stability, high SRI (102) and BS 476-3 fire rating
Limitations & considerations
- Aromatic polyurea, so it chalks and discolours under prolonged UV unless overcoated with Nitoproof UVR Topcoat (cosmetic only, no loss of performance)
- Hand application limits practical film build to ~1.5 mm DFT and is slower per square metre than machine spraying on very large open roofs
- Short 1-hour pot life at 23°C means only the quantity that can be laid quickly should be mixed at a time
- Tight application window: concrete must be at 75% design strength, RH ≤75%, surface ≥5°C and ≥3°C above dew point, and no application above 85% ambient RH or with rain imminent
- Flammable components (Part A flash point 45°C, Part B 26°C) requiring control of ignition sources and good ventilation
- Must not be diluted, and the correct primer (Nitoprime 31 for dry, Primer 195 for damp) must be matched to substrate condition
- Primers and the UVR topcoat may cause sensitisation, requiring full PPE
- Higher material cost than acrylic or single-component PU membranes, justified on performance and service life
Selection & best practice
Treat WH100 as a system, not a single product. Confirm the concrete is sound and has reached at least 75% of design strength, then prepare the surface by abrasive or shot blasting (ASTM D4259), fill blow holes and imperfections, and prime correctly, Nitoprime 31 for sound dry concrete and steel, Fosroc Primer 195 for damp concrete, applied at roughly 0.25 kg/m² on concrete and 0.15 kg/m² on steel and allowed to go touch-dry. Verify surface temperature is at least 5°C and 3°C above dew point and that ambient RH is below 85% before opening any pack. Mix Part A and Part B at exactly A100:B6 by weight with a slow-speed drill and paddle for 3-5 minutes, mix only what the crew can lay within the 1-hour pot life, and always spike-roll each pass to drive out entrapped air. For vertical and upstand surfaces add the WH100 Thickener (one 400 g pack per 25 kg Part A) to hold the film without slumping. Build to the specified 1.5 mm DFT, protect from rain and traffic during cure, and where the roof is UV-exposed or needs a fire rating overcoat with Nitoproof UVR Topcoat. For green roofs, let the membrane fully cure before placing soil.
Specifications
| Product type | Hand-applied, two-component, rapid-curing hybrid (aromatic) polyurea waterproofing and protective coating |
| Components | Part A ISO (isocyanate) + Part B Amine |
| Mixing ratio | A100 : B6 by weight (A100 : B8 by volume) |
| Viscosity at 20°C | Part A ISO 5,000-10,000 mPa·s (25°C); Part B Amine 5 mPa·s |
| Density at 20°C | Part A ISO 1.3 g/ml; Part B Amine 0.9 g/ml |
| Tensile strength | 6 MPa (ASTM D412) |
| Elongation at break | >400% (ASTM D412) |
| Tear resistance | 28 N/mm (ASTM D624C) |
| Hardness | 71 Shore A (ASTM D2240) |
| Puncture resistance | 550 N (ASTM E154) |
| Moisture vapour transmission rate (MVTR) | 5.8 g/m²/day (ASTM E96) |
| Crack bridging | 2 mm – Pass (ASTM C836) |
| Pot life | 1 hour at 23°C |
| Service temperature | -20°C to +80°C |
| Normal dry film thickness (DFT) | 1.5 mm |
| Cure / trafficability | Careful foot traffic after ~2 hrs; light traffic ~24 hrs; fully serviceable in 2-3 days (temperature dependent) |
| Primers | Nitoprime 31 (sound dry concrete / steel); Fosroc Primer 195 (damp concrete) |
| Primer application rate | ~0.25 kg/m² on concrete; ~0.15 kg/m² on steel |
| Root resistance | CEN/TS 14416 |
| Fire rating (with Nitoproof UVR Topcoat) | BS 476-3: EXT F.AA |
| Solar Reflectance Index (with UVR Topcoat, white) | 102 (ASTM E1980) |
| Certification | British Board of Agrément (BBA) Certificate 23/7075 |
| Flash points | Part A ISO 45°C; Part B Amine 26°C; Equipment Cleaner 44°C |
| Shelf life / storage | 12 months in original unopened containers, dry and air-conditioned, +5°C to +30°C |
Industry use cases
Commercial and IT podium decks (Gurugram / Noida)
Seamless waterproofing of landscaped podium and basement-top decks above occupied parking and retail, where movement accommodation and a joint-free membrane matter more than spray speed.
Green roofs and planter boxes
Root-resistant (CEN/TS 14416) membrane under soil and planting on terrace gardens and biophilic roofs; membrane is allowed to fully cure before soil placement.
Stadiums and spectator stands
Tough, trafficable, seamless coating for stadium stands and terraced seating decks exposed to crowd loading, foot traffic and weather.
Industrial and service roofs
Waterproofing of plant-room and service roofs and congested roof areas where bringing in plural-component spray rigs is impractical, using hand application instead.
Steel structures and protective coating
Corrosion and abrasion protection of blast-cleaned steel (SA1, ISO 8501-1) on structures, tanks and walkways, primed with Nitoprime 31 or Primer 195.
Residential terraces and balconies
Seamless waterproofing of terraces, balconies and chajjas with intricate detailing that is difficult to spray, finished with UVR Topcoat for colour stability.
Frequently asked questions
Is Fosroc Polyurea WH100 a true polyurea or a coating?
Does WH100 need spray equipment like normal polyurea?
Will the colour fade or change on the roof?
Which primer should be used and on what substrate?
What thickness and how long before the roof can be used?
How does WH100 compare with sheet membranes and other liquid systems?
How we position Fosroc Polyurea WH100
Within the Fosroc range, Polyurea WH100 is the hand-applied member of the polyurea family and pairs directly with its own ecosystem, Nitoprime 31 and Fosroc Primer 195 as primers, the WH100 Thickener for vertical work, and Nitoproof UVR Topcoat for UV/colour stability and fire rating. Where machine application is viable on large open roofs, Fosroc’s sprayed grades (such as Polyurea WPE and the WH/WHE spray series) are the higher-throughput alternative, and Brushbond/Nitoproof acrylic-PU liquid membranes are the lower-cost, lower-performance options for less demanding roofs. Against the wider market, WH100 competes with Sika’s Sikalastic liquid-applied and polyurea systems, BASF/MBS (Master Builders Solutions) MasterSeal membranes, Pidilite Dr. Fixit’s high-end PU and polyurea coatings, and STP Ltd’s polyurea and APP membranes. Its honest niche is buyers who want genuine polyurea toughness and a seamless, certified membrane but need it laid by hand, on terraces, podiums, planter boxes, service roofs and detailed areas, without the capital cost and access constraints of plural-component spraying. Space Arc Engineering, as an authorised Fosroc distributor serving Delhi NCR and Pan-India, supplies WH100 as a complete primer-membrane-topcoat system with method-statement support rather than as a standalone tin.
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