STP ShaliCryl 215
A UV-stable acrylic membrane built for peak summer glare and monsoon lash, bridging hairline cracks and keeping exposed roofs and facades dry for years.
What is it?
Single-component, UV-resistant elastomeric acrylic coating that cures into a tough, flexible, crack-bridging waterproof film over exposed concrete and masonry.
Where is it used?
Exposed RCC roofs, sloped and domed roofs, parapets, terraces, and complex-geometry facades and walls, anywhere sunlight hits directly.
Why use it?
Stays flexible and UV-stable through peak heat and monsoon cycles, bridges cracks up to 1 mm, resists carbonation, and keeps algae and fungal growth off exterior surfaces.
How is it applied?
Two coats by brush or roller at about 155 ml/m2 each over a primed, cured surface, building a 150-160 micron dry film; an optional topcoat extends service life further.
About STP ShaliCryl 215
ShaliCryl 215 is STP Limited’s answer to a problem every site engineer in Delhi NCR knows: exposed facades that crack, chalk and leak within a couple of monsoons because the coating couldn’t take the UV load and thermal cycling. It’s a single-component acrylic elastomeric coating, not a bituminous or PU membrane, formulated to cure into a flexible film that keeps moving with the substrate instead of cracking off it. STP also calls out an anti-carbonation function: the 150-160 micron dry film slows CO2 ingress into concrete, which matters for older RCC where rebar corrosion is the real long-term threat.
On site it’s used two ways: standalone on sloped roofs, domes and awkward-geometry walls where sheet or torch-applied membranes are impractical, and as the UV-protective top layer over a liquid membrane like ShaliCryl LM, which itself isn’t meant for permanent sun exposure. It conforms to ASTM D-6083 and comes from a company making waterproofing chemicals in India for over eight decades, so this chemistry sits alongside a deep bench of complementary primers, crack fillers and topcoats meant to work as one system.
The technical insight
The numbers reward a closer read. Elongation of 300% at 14 days (ASTM D-6083) is what delivers the 1 mm crack-bridging claim; a stiffer coating would just crack over a moving hairline fracture. Shore A hardness of 70-72 keeps the film firm enough to resist dust pickup while staying elastomeric. The CO2 diffusion figure is the one most buyers skip: an equivalent air layer thickness over 70 m at 80 microns DFT, translating to roughly 177 mm of equivalent concrete, means real anti-carbonation work. Rapid chloride permeability (ASTM C1202-97) reading “very low” matters more near coastal sites than in Delhi NCR, where carbonation is the bigger threat. The SRI of 105 in white is a genuine cool-roof number.
Where it is used
- Exposed RCC roof slabs, terraces and flat roofs taking direct monsoon and summer sun
- Sloped and domed roofs where sheet or torch-applied membranes are hard to lay
- Parapet walls, chajjas and complex-geometry facade details
- UV-protective top coat over ShaliCryl LM and other liquid waterproofing membranes
- External plastered walls on older buildings showing early carbonation or dampness
- Above-grade water tank exteriors and overhead tank walls
- Metal and masonry surfaces on industrial sheds needing a flexible weatherproof coat
- Re-waterproofing of previously coated exteriors during facade refurbishment
Key advantages
- 300% elongation at 14 days gives real crack-bridging, not just a marketing figure
- UV cross-link curing means it’s built for direct sun long-term, unlike PU membranes that need burial or a topcoat
- Anti-carbonation performance equivalent to 177 mm of concrete protects rebar in older structures
- Single component, so no mixing ratios to get wrong on site
- SRI of 105 in white gives a genuine cool-roof benefit alongside waterproofing
- Dust, algae and fungal resistant finish keeps exposed facades looking clean for longer
- Works on complex geometry such as domes and curved walls where sheet membranes can’t be laid
- Backed by a documented ASTM D-6083 and ASTM G23 test package, not just in-house claims
Limitations & considerations
- Tensile strength is modest at 0.72 MPa; it’s a flexible wall and roof film, not a wearing surface for foot or vehicular traffic
- Crack bridging tops out at 1 mm; wider cracks need PlastiSeal or PlastiSeal P treatment first
- Performance depends heavily on priming with ShaliPrime WB; skipping primer on a chalky substrate is the most common site failure
- Two-coat system needs a 6-8 hour recoat gap and 72 hours before traffic, so it needs weather planning around monsoon showers
- Not a substitute for a structural waterproofing membrane in below-grade, submerged or continuously ponded areas
- Colour is added on site via stainer, so shade consistency across a large facade depends on applicator discipline
Selection & best practice
Don’t skip the surface prep sequence on the data sheet. Wash down loose material, fill voids with polymer mortar (ShaliSBR Latex : water : cement : sand at 1:1:5:12.5), treat cracks up to 3 mm with PlastiSeal and wider ones with PlastiSeal P after a proper V-cut, and cure repairs for 10 days before coating. Prime with ShaliPrime WB at 8-10 m2/L and let it dry fully. Apply ShaliCryl 215 undiluted in two coats at roughly 155 ml/m2 each, stirring the stainer in slowly and letting the mix stand briefly so trapped air escapes before application, since rushing this step is what causes pinholing. Avoid coating just before rain, and keep the coated area free of traffic for 72 hours after the final coat.
Specifications
| Chemistry / Standard | Single-component acrylic elastomeric coating; conforms to ASTM D-6083 |
| Density | 1.30 ± 0.02 g/cc |
| Solids content | 57-60% by weight |
| Viscosity | 20,000 ± 2,000 cps @ 30°C |
| Recommended dry film thickness | 150 microns (150-160 µ film) |
| Theoretical coverage | 3.25-3.50 m²/L per coat (≈155 ml/m² per coat, 2 coats) |
| Elongation at break (14 days) | 300% (ASTM D-6083) |
| Crack-bridging ability | Up to 1 mm |
| Pack sizes | 5 L and 20 L |
Industry use cases
Residential terraces, Delhi NCR
Homeowners re-waterproofing an exposed RCC roof before monsoon, usually over a ShaliCryl LM base with ShaliCryl 215 as the UV-stable top layer.
Commercial and institutional roofs
Flat or gently sloped roofs on schools, offices and hospitals where long-term UV exposure and low maintenance matter more than upfront cost.
Industrial sheds and warehouses
Sloped or domed roof profiles where torch-applied or sheet membranes can’t follow the geometry cleanly.
Facade refurbishment, older buildings
Plastered exterior walls on 15-20 year old structures showing early carbonation signs, coated as part of a broader repair scope.
Overhead and above-grade water tanks
Tank exteriors exposed to direct sun, where anti-algae and anti-fungal performance keeps the tank looking maintained.
Frequently asked questions
Can ShaliCryl 215 be walked on like a terrace floor coating?
How much ShaliCryl 215 do I need for my roof?
Does it need a primer, or can I apply it directly on bare concrete?
Will it fix a cracked roof, or do I need to treat cracks separately first?
What colours does it come in, and does colour affect performance?
How is this different from ShaliCryl LM?
How we position STP ShaliCryl 215
Within the STP range, ShaliCryl 215 is the UV-facing topcoat of a waterproofing system rather than a standalone fix: pair it with ShaliPrime WB for priming, PlastiSeal or PlastiSeal P for crack treatment, ShaliSBR Latex for repair mortar, and ShaliCryl LM underneath where a dedicated membrane is needed before the UV coat goes on. Against Fosroc’s range, the closer comparison isn’t Nitoproof 600, a below-grade, non-UV-stable PU membrane, but Nitoproof 725, Fosroc’s own exposed-roof, UV-stable, cool-roof elastomeric coating. A specifier already standardised on Fosroc systems, or wanting a fire-rated PU-hybrid chemistry with wider crack bridging, would reasonably pick Nitoproof 725; ShaliCryl 215 remains the more accessible acrylic option for straightforward exterior wall and roof UV protection.
Fosroc Nitoproof 725 — Specifiers who need a fire-rated (ASTM E108 Class A), PU-hybrid exposed-roof coating with wider crack bridging (up to 2 mm) and are already standardised on Fosroc systems would reasonably choose Nitoproof 725 over ShaliCryl 215.
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