STP ShaliProtek PuR 40
A two-component, brush- or spray-applied elastomeric polyurea that lays down a seamless, high-strength waterproofing membrane on concrete and steel.
What is it?
A two-component (63:37 by weight) brushable elastomeric polyurea waterproofing and protective coating from STP Limited that cures to a tough, seamless film.
Where is it used?
Concrete roofs, non-potable water tanks, foundation walls, metal surfaces, bitumen membranes, PU foam insulation and concealed under-tile areas.
Why use it?
It combines very high mechanical strength (5 MPa tensile, ~500% elongation) with early rain resistance and a generous 30-35 minute pot life, so a hand-mixed polyurea becomes practical on site.
How is it applied?
Prime the substrate, mix Component A and B for 3-5 minutes, then apply by brush, roller or airless spray in two coats to reach the specified dry film thickness.
About STP ShaliProtek PuR 40
STP ShaliProtek PuR 40 is a two-component, brushable elastomeric polyurea coating built for long-term waterproofing and protection of construction surfaces. Unlike spray-only polyureas that need dedicated plural-component machinery, PuR 40 is formulated with an extended pot life of 30 to 35 minutes, which lets contractors mix and apply it by brush, roller or airless spray. That single change makes true polyurea chemistry usable on the kind of smaller roofs, tanks and repair jobs across Delhi NCR and Pan-India where hauling spray rigs is neither practical nor economical.
The coating is supplied as a white or grey liquid in a 12.5 kg unit pack holding both components, mixed at 63:37 by weight (roughly 1:1 by volume). Once combined and cured, it develops the properties engineers expect from a premium membrane: tensile strength around 5 MPa, elongation at break near 500%, Shore A hardness of about 70, and water absorption below 0.2%. It bonds to concrete at over 2.5 MPa and holds its performance across a service range of -35 to +80 degrees C, so it stays flexible through both North Indian winters and terrace-level summer heat.
The technical insight
Polyurea forms when an isocyanate reacts with an amine-terminated resin, and that reaction is what sets this product apart from ordinary polyurethane membranes. The bond it creates cures fast and is far less sensitive to moisture and humidity than a urethane linkage, which is why ShaliProtek PuR 40 shows excellent resistance to early rain and can be trafficked in 18 to 24 hours. The trade-off in most polyureas is a pot life measured in seconds, forcing spray-only application. STP has slowed the reaction chemistry just enough to give a 30 to 35 minute working window and a tack-free time of one to two hours, so the applicator gets the durability, tear resistance (45 N/mm) and elongation of a polyurea while keeping the simple brush-and-roller method of a coating. The result is a seamless, joint-free film that moves with the structure and shrugs off standing water.
Where it is used
- Waterproofing flat and low-slope concrete roofs and terraces
- Lining non-potable water tanks and sumps
- Coating exterior foundation and retaining walls below grade
- Protecting metallic surfaces and steel structures against corrosion and moisture
- Overlaying aged bitumen membranes and existing waterproofing coatings for refurbishment
- Sealing over new PU foam insulation as a protective wear coat
- Concealed under-tile waterproofing on bathrooms, balconies and wet areas
- Bridging and protecting concrete substrates subject to structural movement
Key advantages
- True polyurea durability with a hand-mixable 30-35 minute pot life, no spray rig required
- Excellent resistance to early rain, reducing weather-window risk on site
- Very high mechanical strength: ~5 MPa tensile, ~500% elongation, 45 N/mm tear resistance
- Strong adhesion (>2.5 MPa) to a wide range of substrates including concrete, steel and bitumen
- Seamless, joint-free membrane that eliminates the weak laps of sheet systems
- Wide service temperature band of -35 to +80 degrees C for Indian roof conditions
- Flexible application by brush, roller or airless spray to suit any job size
- Very low water absorption below 0.2% for reliable long-term performance
Limitations & considerations
- Contains isocyanate and is flammable, so trained applicators, ventilation and PPE are mandatory
- Not suitable for potable (drinking) water tanks or contact with foodstuffs
- Needs UV protection: exposed installations require a topcoat such as ShaliProtek 2AC PU TC for long-term durability
- Requires a compatible primer (ShaliPrime PUM / 2E or ShaliPoxy CTE 103 MI for anti-root) and cannot be applied to bare substrate
- Substrate must be sound and dry (moisture content under 3%) with new concrete cured 28 days and at 75% design strength
- Application limited to +10 to +45 degrees C substrate and ambient temperature; must not be diluted with thinner
Selection & best practice
Start with a clean, sound, dry substrate: remove all loose gravel, dirt, oil, grease and curing compound by dry-air jet and mechanical grinding, and confirm moisture content is below 3%. New concrete must be at least 28 days old and have reached 75% of its design strength; on steel, blast to an SA 2 to SA 2½ profile. Repair cracks by cutting a V-groove and filling with PMC mortar (ShaliCrete:Cement:Sand at 1:2:5), and form a 50 mm x 50 mm coving at all wall-floor junctions. Prime with ShaliPrime PUM, ShaliPrime 2E or the anti-root ShaliPoxy CTE 103 MI and let it dry fully. Mix Component A and B with a slow-speed paddle for 3 to 5 minutes to a uniform colour, keeping the paddle submerged to avoid trapping air, and never mix by hand or add thinner. Apply the first coat by brush, roller or airless spray, allow 8 to 12 hours to dry, then apply the second coat after 12 hours to build the specified DFT. For waterproofing duty aim for 1000 microns in two coats; for protective duty 100 to 200 microns is enough. Clean tools immediately with STP Thinner before the material hardens.
Specifications
| Chemistry | Two-component elastomeric polyurea (contains isocyanate) |
| Mixing ratio | Component A : B = 63 : 37 (w/w), 1:1 (v/v) |
| Consumption | 0.2-0.4 kg/m² protective coat; 2-2.2 kg/m² waterproofing coat (IS 101) |
| Recommended DFT | 100-200 microns protective; 1000 microns waterproofing in 2 coats |
| Pot life | 30-35 minutes (100 g sample, ASTM D 2471) |
| Tensile strength | 5 ± 0.05 MPa at 14 days (ASTM D 412) |
| Elongation at break | 500 ± 100% at 14 days (ASTM D 412) |
| Adhesion to concrete | >2.5 MPa (ASTM D 4541) |
| Service temperature | -35 to +80 degrees C |
| Packaging & shelf life | 12.5 kg unit pack (A+B); 12 months in sealed storage at 5-38 degrees C |
Industry use cases
Roofing & Terraces
Seamless waterproofing of flat and low-slope concrete roofs where movement, ponding and early monsoon rain demand a high-elongation, fast-setting membrane.
Water Retaining Structures
Lining of non-potable water tanks, sumps and reservoirs that need a tough, low-absorption polyurea film resistant to constant water contact.
Industrial & Metal Structures
Protective coating for steel tanks, ducting and plant surfaces blasted to SA 2½, guarding against corrosion and moisture ingress.
Infrastructure Refurbishment
Overlay for aged bitumen membranes and failed coatings, restoring waterproofing without stripping the existing system back to substrate.
Below-Grade & Concealed Areas
Foundation walls and under-tile wet areas where a durable, crack-bridging membrane is buried and protected from UV.
Frequently asked questions
Is ShaliProtek PuR 40 a polyurethane or a polyurea?
Can it be brush-applied, or do I need a spray machine?
How much material do I need per square metre?
Can I use it to waterproof a drinking water tank?
Does it need a primer and a topcoat?
What is the pack size and shelf life?
How we position STP ShaliProtek PuR 40
ShaliProtek PuR 40 is the hand-applied, high-strength waterproofing option in STP’s polyurea range. Where a project calls for machine-sprayed, ultra-fast-curing polyurea on large decks or industrial floors, step up to STP ShaliProtek PuR 100, the 100% solids, spray-applied polyurea. For UV-exposed decks and terrace finishes, pair PuR 40 with the ShaliProtek 2AC PU TC topcoat and the appropriate ShaliPrime primer to complete the system. Among the other brands we stock, teams that prefer a single-component, ready-to-use liquid membrane for concealed below-grade work often specify Fosroc Nitoproof 600, while Dr. Fixit and Sika offer acrylic and cementitious alternatives for lighter-duty terrace waterproofing. As an authorised STP distributor and applicator across Delhi NCR and Pan-India, Space Arc can supply the full ShaliProtek system and advise on the right membrane for your substrate and exposure.
Fosroc Nitoproof 800 — Choose Nitoproof 800 when the deck is fully exposed to sunlight and foot traffic and you want a factory-matched UV-stable polyurethane topcoat built into the system, rather than adding a separate topcoat over a polyurea.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.