STP ShaliPrime 2E SF
Two-component, 100% solids epoxy primer that seals porous concrete and blasted steel before epoxy or PU flooring — zero VOC, so it works where air quality rules are strict.
What is it?
A 2K solvent-free, moisture-insensitive epoxy primer from STP Limited. Transparent, 100% solids by weight and volume, mixed at 79.75:20.25 (A:B by weight).
Where is it used?
On prepared concrete floors, walls and blast-cleaned steel before epoxy or PU floor toppings, screeds, repair mortars and elastomeric PU liquid membranes.
Why use it?
It is VOC-free, tolerates residual substrate moisture up to about 10%, and locks down porous concrete so the finished topping does not blister from escaping air.
How is it applied?
Brush, roller, spray or squeegee at 0.3–0.5 kg/m² on horizontal concrete, 100–150 micron DFT per coat. Overcoat within 6–12 hours; pot life is roughly 2 hours at 27°C.
About STP ShaliPrime 2E SF
ShaliPrime 2E SF sits at the first — and most unforgiving — step of any resin flooring job: the primer coat. It is a two-component epoxy from STP Limited, supplied as resin (Part A) and hardener (Part B) that mix to a transparent, 100% solids liquid. Because there is no solvent to flash off, nothing evaporates during cure, film build is predictable, and the primer can go into occupied or ventilation-restricted buildings without odour complaints or flammability paperwork. The “SF” grade exists precisely for pharma plants, food factories, hospitals and basements where the standard solvented 2E cannot be used.
For applicators, the practical draw is its moisture insensitivity. Green-ish concrete with moisture up to around 10% — a constant headache on fast-track Indian sites — can still be primed, provided there is no active rising damp. Once down, it penetrates open-textured concrete, seals the pores, and gives the subsequent ShaliFloor or ShaliFix layer a substrate that pulls at 1.6 MPa adhesion after 7 days. Space Arc Engineering stocks both the 25 kg and 6 kg units and supports application across Delhi NCR and pan-India projects.
The technical insight
A porous concrete slab behaves like a sponge full of air. Lay a self-levelling epoxy straight onto it and, as the slab warms through the day, expanding air vents upward through the wet resin — the pinholes and blisters every flooring contractor has had to grind out. ShaliPrime 2E SF works by getting there first: its low-viscosity mix wicks into capillaries and laitance-free pores, then cross-links into a rigid film that plugs those air paths. Being 100% solids, the wet film thickness equals the dry film thickness, so a 100–150 micron coat stays a 100–150 micron coat with no solvent-retention risk at depth. The epoxy-amine chemistry is also tolerant of dampness during cure, which is why the TDS accepts substrate moisture below 10% where conventional primers demand a bone-dry slab. On highly absorbent patches the primer soaks away and leaves light, dry-looking areas — the correct response is a second coat there, not a thicker first coat.
Where it is used
- Priming concrete floors before epoxy toppings such as ShaliFloor 3ES, ShaliFix EM and ShaliFloor SL TC 3 PU
- Primer coat under elastomeric PU liquid-applied membranes and trafficable deck coating systems
- Industrial floors in factories, warehouses, cold stores and aircraft hangars
- Ramps, car parks, parking bays, pedestrian walkways and roof decks under heavy-duty traffic systems
- Laboratories, hospitals, food and beverage plants, dairies, commercial kitchens and high-tech manufacturing areas
- Priming blast-cleaned steel (ISO Sa 2½) before epoxy or polyurethane coatings
- Broadcast (quartz-scattered) primer layer at 0.60–0.80 kg/m² in bonded screed systems
- Scratch/intermediate layer when blended 1:1.4 by weight with STP Quartz Sand up to 2 mm thickness
Key advantages
- Zero VOC and solvent-free — usable in occupied buildings, basements and air-quality-controlled plants without fume management
- Moisture insensitive: tolerates substrate moisture up to about 10%, cutting waiting time on new slabs
- 100% solids by weight and volume — no film shrinkage, honest coverage arithmetic, no solvent entrapment
- Seals porous concrete and stops air release that causes pinholes and bubbles in the finished epoxy topping
- Strong mechanical grip: 1.6 MPa adhesion to concrete at 7 days, above the typical cohesive strength of screed-grade concrete
- Dual-substrate: one primer for both concrete and blast-cleaned steel in the same flooring package
- Fast programme: touch dry in 1–2 hours, overcoatable in 6–12 hours, light foot traffic next day
- Withstands occasional 120°C exposure, so steam-cleaned food and pharma floors are within scope
Limitations & considerations
- Not for substrates with rising dampness, osmosis risk or relative humidity above 75% — active moisture from below will defeat any epoxy primer
- Do not apply over asphalt, weak or friable concrete, unmodified sand-cement screeds, PVC tiles or substrates that move, such as steel walkways
- Not recommended for exterior slabs on grade in freeze-thaw exposure
- Working window is tight: pot life is about 2 ± 0.5 hours at 27°C and shortens further in hot Indian summers — batch sizes must match crew speed
- Application limited to +10°C to +40°C substrate and ambient temperature; concrete should be 14–21 days old or below 7–8% moisture
- As a transparent primer it offers no UV colour stability — it can fade and chalk if left exposed, so overcoat within the 6–12 hour window
Selection & best practice
Surface preparation decides the outcome. Mechanically prepare concrete by abrasive blasting or scarifying until laitance is gone and the texture is open; cut out weak concrete and expose blowholes fully, then vacuum off every trace of dust. Steel must be blasted to ISO Sa 2½ and primed immediately, before flash rust returns. For mixing, stir Part A first, add all of Part B, and mix 3 minutes with a slow-speed stirrer at 300–400 rpm; let the mix stand 5 minutes to release entrapped air, then transfer to a clean container and remix briefly. Apply by brush, roller, spray or squeegee at 0.3–0.5 kg/m² on horizontal concrete, targeting 100–150 microns per coat. Watch for light, dry-looking patches where porous concrete has drunk the primer — give those areas a second coat rather than risking pinholes. Allow 6–12 hours (or overnight) before the topping goes down, control site dust and draughts while the film is wet, and clean tools with STP Thinner before the material sets — cured primer only comes off mechanically.
Specifications
| Mixing ratio (A : B, by weight) | 79.75 : 20.25 |
| Solids content | 100% by weight and volume (solvent-free, zero VOC) |
| Coverage, horizontal concrete primer | 0.3–0.5 kg/m² (broadcast primer 0.60–0.80 kg/m²; vertical metal 0.14–0.30 kg/m²) |
| Recommended DFT per coat | 100–150 microns |
| Pot life at 27°C | 2 ± 0.5 hours |
| Touch dry / overcoating time | 1–2 hours at 150 µ WFT / 6–12 hours |
| Adhesion to concrete, 7 days | 1.6 MPa |
| Mixed density | 1.33 ± 0.03 g/cc |
| Pack sizes / shelf life | 25 kg and 6 kg units / 12 months at 5–38°C, sealed |
Industry use cases
Pharmaceutical & Cleanroom
Priming production and corridor floors ahead of self-levelling epoxy where zero-VOC application is mandatory and shutdown windows are short — touch dry in 1–2 hours keeps validation schedules intact.
Food, Beverage & Dairy
Base coat under hygienic epoxy screeds in processing halls and kitchens; 120°C occasional temperature resistance covers routine steam-cleaning regimes without primer breakdown.
Warehousing & Logistics
Sealing power-floated and porous slabs in warehouses, cold stores and hangars before heavy-duty toppings, so racking-leg point loads bear on a well-bonded system rather than laitance.
Car Parks & Traffic Decks
Primer within trafficable deck coating build-ups on ramps, parking bays and roof decks — including the quartz-broadcast layer at 0.60–0.80 kg/m² for bonded wearing courses.
Industrial Structures & Steel
One-material priming of both concrete plinths and Sa 2½ blasted steelwork before epoxy or PU finishes, simplifying inventory on plant maintenance shutdowns.
Frequently asked questions
What is the difference between ShaliPrime 2E and ShaliPrime 2E SF?
How much ShaliPrime 2E SF do I need per square metre?
Can I apply it on new or damp concrete?
How long before I can lay the epoxy topping over it?
What is the pot life, and how should we batch it on site?
Does it work on steel as well as concrete?
How we position STP ShaliPrime 2E SF
ShaliPrime 2E SF is the entry coat of STP’s resin flooring family: it is designed to be overcoated with ShaliFloor 3ES or ShaliFloor SL TC 3 PU self-levelling systems, ShaliFix EM epoxy repair mortar, or an elastomeric PU liquid membrane, with STP Quartz Sand for broadcast and scratch-coat work and STP Thinner for tool cleaning. Specifiers already standardised on Fosroc flooring will find the equivalent role filled by Nitoprime 25 under Nitoflor toppings — both are stocked by Space Arc, so mixed-brand sites can be supplied from one counter. For the topping itself, we also supply Sika and MC-Bauchemie floor systems where the consultant’s specification calls for them.
Fosroc Nitoprime 25 — Specifiers running a Fosroc Nitoflor flooring package usually keep the primer in-family with Nitoprime 25, though its solvented formulation makes ShaliPrime 2E SF the safer pick where zero-VOC application is mandated.
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