STP ShaliCem EWP 150
The superior grade of STP’s two-part acrylic cementitious system, delivering a flexible, UV-resistant, crack-bridging waterproof membrane for concrete and masonry.
What is it?
A two-component, acrylic-polymer-modified cementitious coating from STP Limited. A grey powder and a milky-white liquid are blended on site to form a seamless, elastomeric waterproof membrane. The 150 grade is the enhanced version of the standard ShaliCem EWP.
Where is it used?
Roof slabs, terraces, basement rafts against rising damp, water-retaining structures, and below-tile in kitchens and toilets. Suits both flat and inclined concrete and masonry.
Why use it?
It bridges shrinkage cracks, stays flexible, breathes to release vapour, and carries USFDA 175.300 clearance for potable-water contact, so one coating handles both structural and drinking-water tanks.
How is it applied?
Mix component A into component B with a slow-speed paddle, let it stand to de-air, then brush, roller, trowel or spray two coats to a 1 mm dry film over a saturated-surface-dry substrate, and moist-cure.
About STP ShaliCem EWP 150
STP’s ShaliCem EWP 150 sits at the top of the ShaliCem EWP family, a two-part waterproofing coating that Indian consultants have specified for years on roofs, tanks and below-grade slabs. Component A is a graded grey powder and component B a milky-white acrylic polymer liquid; combined on site at roughly 14.8 to 5.2 by weight, they cure into a tough, seamless film that behaves more like a rubber membrane than a rigid render. That film resists waterborne salts and atmospheric gases while remaining breathable, so trapped vapour can escape instead of blistering the coating from behind.
For engineers and applicators, the appeal is the balance of properties in a single product. It bonds to both porous and non-porous surfaces without a separate primer, tolerates the movement that fine shrinkage cracks introduce, and shrugs off UV so exposed terraces do not need an extra sacrificial layer. Because it is solvent-free, non-toxic and cleared under USFDA 175.300 for contact with potable water, the same drum can be used on a drinking-water reservoir and on a planter box on the floor above. Space Arc Engineering supplies and applies it across Delhi NCR and Pan-India, with site guidance so the coating is mixed, laid and cured the way the data sheet intends.
The technical insight
The waterproofing comes from the acrylic polymer, not just the cement. As the slurry cures, cement hydration builds the hard mineral matrix while the acrylic dispersion coalesces into a continuous, flexible film that laces through and over that matrix. The result is an elastomer-reinforced cementitious layer: rigid enough to bond monolithically to concrete, yet elastic enough to stretch across a hairline crack rather than fracture with it, with a crack-bridging capability of up to about 1.5 mm and elongation near 80 percent. That flexibility is why it holds on structures that flex with thermal and load cycling, where a plain cement render would craze. The film is also vapour-permeable by design, so it blocks liquid water under head while letting the slab breathe outward, which prevents the osmotic blistering that traps moisture behind non-breathable membranes. Two coats to a 1 mm dry film give the continuity and thickness the system relies on; a single thin pass leaves pinholes and weak spots that undermine the whole membrane.
Where it is used
- Waterproofing roof slabs, terraces and exposed decks where UV resistance is needed
- Basement rafts and retaining walls treated against rising dampness and ground moisture
- Water-retaining structures such as tanks and reservoirs, including potable-water tanks
- Below-tile tanking in kitchens, toilets and other internal wet areas
- Sealing damp patches and construction joints on walls prone to water ingress
- Podiums and planter boxes where a flexible, breathable membrane is required
- Concrete and masonry substrates on both flat and vertical or inclined faces
- Roofs and terraces that later receive a screed or trafficable PU topcoat for protection
Key advantages
- Flexible, elastomeric film bridges fine shrinkage cracks instead of fracturing with them
- UV resistant, so exposed roofs and terraces need no sacrificial sunscreen layer
- Breathable and vapour-permeable, releasing slab moisture and avoiding blistering
- Cleared under USFDA 175.300 for contact with potable water
- Solvent-free, non-toxic and environmentally friendly, safe for enclosed wet areas
- Bonds to both porous and non-porous surfaces with no separate primer coat
- Applied by brush, roller, trowel or spray, suiting site conditions and geometry
- Seamless membrane with no laps or joints for water to track through
Limitations & considerations
- The material must never be diluted with water; adding water weakens the film and voids performance
- Needs a saturated-surface-dry substrate with no standing water, which takes pre-wetting discipline
- Two coats to a full 1 mm dry film are essential; a single thin coat leaves pinholes
- Requires moist curing for 2 to 3 days plus 3 days air-drying before water submersion, so it is not instant
- Sharp objects and dragged reinforcement can puncture the membrane before it is protected
- The mixed slurry has a 45 to 60 minute working time, so only batch what the crew can lay in that window
Selection & best practice
Prepare the substrate first: clean off dust, laitance and contaminants by grinding or water blasting, and make good cracks and honeycombing with a PMC mortar or ShaliFix FRM. Pre-wet dense concrete at least twice, 30 minutes apart, so the surface is damp but free of standing water at the moment of application. Add the whole of component A slowly into all of component B and mix at 300 to 400 rpm to a lump-free slurry, then let it stand four to five minutes to release air. Lay the first coat by brush, roller, trowel or spray, and only apply the second coat once the first is dry, building a full 1 mm dry film in two coats. Where extra reinforcement is wanted at junctions, embed glass fabric between coats. Air-dry three to six hours with no curing water, protecting from rain, direct sun above 40 degrees C and wind, then fog-spray and keep the surface damp for two to three days before three days of air-drying ahead of any submersion. Protect the finished membrane with a PCC screed gauged with ShaliPlast IW, or a ShaliProtek PU HA coating on trafficable roofs.
Specifications
| Product type | Two-part acrylic-polymer-modified cementitious elastomeric coating (superior grade of ShaliCem EWP) |
| Form and colour | Component A powder (grey); Component B liquid (milky white) |
| Mixing ratio (A:B) | 14.8 : 5.2 by weight (37 : 13 w/w) |
| Mixed density | 1.80 ± 0.03 g/cc (ASTM D 1475) |
| Working time | 45 to 60 minutes at 30 degrees C, 55% RH |
| Crack-bridging ability | Up to 1.5 mm (ASTM C 836) |
| Recommended DFT | 1 mm in 2 coats |
| Theoretical coverage | 1.6 to 1.8 kg/m² per mm in 2 coats (varies with surface profile) |
| Standards / approvals | DIN 1048 water penetration; BS 1881 Part 5; USFDA 175.300 (potable water contact) |
| Packaging and shelf life | 20 kg and 50 kg units; 12 months at 5 to 40 degrees C sealed |
Industry use cases
Water infrastructure and utilities
Lining potable-water tanks and reservoirs where the coating’s USFDA 175.300 clearance and elastomeric crack-bridging keep stored water safe and leak-free.
Residential and commercial buildings
Below-tile tanking in bathrooms, kitchens and balconies, plus terraces and roofs, using a single breathable, UV-resistant membrane.
Basements and below-grade structures
Treating rafts and retaining walls against rising dampness and ground moisture, protected afterwards by a ShaliPlast IW-gauged screed.
Repair and rehabilitation
Re-waterproofing ageing roof slabs and sealing damp patches and joints on walls where movement and fine cracking have defeated rigid renders.
Frequently asked questions
How is ShaliCem EWP 150 different from standard ShaliCem EWP?
Can I use it on a drinking-water tank?
How much material do I need per square metre?
Can I thin it with water to make it brush more easily?
Does it need curing like ordinary concrete?
What packs does it come in and how long does it keep?
How we position STP ShaliCem EWP 150
ShaliCem EWP 150 is the flexible, elastomeric option in STP’s waterproofing range, best where the substrate moves or cracks and a breathable UV-resistant membrane is wanted. Within the same STP family, pair it with ShaliFix FRM to make good cracks and honeycombing before coating, ShaliPlast IW gauged into a protective PCC screed over the membrane, and ShaliProtek PU HA as a trafficable topcoat on exposed roofs; clean tools with STP Thinner. Where a project specifies rigid crystalline or integral protection instead, Space Arc also carries Dr. Fixit and MC-Bauchemie systems, and for consultants standardised on a single house brand we can match the requirement across our Fosroc, Sika and Master Builders Solutions lines.
Fosroc Nitocote CM210 — A specifier standardised on Fosroc, or one needing a documented positive and negative water-pressure rating (5 bar / 3 bar to CEN test), may prefer Nitocote CM210 as the like-for-like two-part elastomeric cementitious coating.
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