Sika Sikafloor-390 N
A tough-elastic, crack-bridging epoxy coating that flexes with a working slab instead of cracking over it — built for demanding industrial and food-grade floors.
What is it?
A two-component, solvent-free, coloured epoxy floor coating with a deliberately tough-elastic film that bridges fine substrate cracks up to around 0.2 mm.
Where is it used?
Production and processing halls, warehouses, food and beverage plants, chemical units, workshops and sheltered exterior service areas laid over sound concrete or screed.
Why use it?
Combines the chemical and abrasion resistance of an epoxy with enough elasticity to accommodate hairline movement, so the finish stays seamless and cleanable rather than telegraphing every slab crack.
How is it applied?
Mixed 85:15 (A:B) by weight, then applied by roller or trowel over a Sika primer as a wearing layer at roughly 1.6 kg/m2 per mm, optionally broadcast with aggregate and sealed.
About Sika Sikafloor-390 N
Sikafloor-390 N sits in a useful middle ground between a hard, rigid epoxy topping and a fully flexible polyurethane deck coating. It is a two-component, solvent-free epoxy at essentially 100% solids, but the resin is formulated to cure tough-elastic rather than glass-hard. That single property change is what the whole product is about: an industrial slab is never perfectly still, and rigid coatings tend to reflect every shrinkage crack and control joint straight through to the surface. The 390 N film stretches locally over those fine cracks — bridging movement of the order of 0.2 mm to the ZG DIBt water-protection criteria — so the floor keeps a continuous, wipe-clean skin even where the concrete underneath is not.\n\nBecause it is coloured and seamless, it also does the day-to-day jobs a good industrial floor coating is expected to do. It resists abrasion (around 75 mg loss on the Taber CS10 test), carries a Shore D hardness of roughly 60 at 14 days, holds bond strength above 1.5 N/mm2 to a properly prepared substrate, and offers very good resistance to a defined range of chemicals. It is documented against EN 1504-2 as a concrete surface-protection system and EN 13813 as a synthetic-resin screed material, and carries cleanroom-relevant particle and VOC emission testing plus indirect food-contact suitability — which is why it turns up so often in food, beverage and pharma-adjacent facilities where hygiene and a defect-free surface both matter.
The technical insight
The mechanism worth understanding is elongation versus rigidity. A standard industrial epoxy is cross-linked to be extremely hard and chemically tight, but that same dense network has almost no give — when the slab beneath opens a shrinkage crack, the coating has nowhere to go and simply splits along the same line. Sikafloor-390 N uses a modified epoxy chemistry that keeps high solids and good chemical resistance while building in enough elastic recovery for the film to strain across a narrow, slowly-opening crack instead of fracturing. That is why the datasheet quotes a crack-bridging figure (about 0.2 mm) rather than only a hardness number. The practical envelope follows from this: it bridges fine, essentially static hairline cracks in the wearing layer — it is not a joint sealant and will not span live, moving structural joints or dynamic cracks, which still need a designed joint detail. Cure is a straightforward exothermic epoxy reaction, so temperature drives everything — pot life runs from about 60 minutes at 10 C down to roughly 10 minutes at 30 C, and full chemical cure lands near 14 days at 10 C, 10 days at 20 C and 7 days at 30 C.
Where it is used
- Seamless wearing-layer flooring in production and processing halls where the slab shows fine shrinkage cracks
- Food, beverage, dairy, brewery and bottling plants needing a hygienic, cleanable, indirect food-contact finish
- Warehouses and distribution floors under foot traffic and light-to-medium wheeled loads
- Chemical manufacturing and handling areas requiring defined chemical resistance and easy decontamination
- Workshops and engineering bays exposed to abrasion, dropped tools and occasional spillage
- Broadcast slip-resistant systems where quartz or aggregate is scattered into the coat and sealed
- Sheltered exterior service areas, loading aprons and covered docks
- Cleanroom-adjacent and pharma support spaces where low particle and VOC emission is specified
Key advantages
- Tough-elastic film bridges fine substrate cracks (~0.2 mm) that would telegraph through a rigid epoxy
- Solvent-free at ~100% solids, so low odour and no solvent shrinkage during cure
- Seamless and coloured — no joints to harbour dirt, easy to wash down and decontaminate
- Very good defined chemical resistance combined with ~75 mg Taber abrasion loss for durability
- Documented to EN 1504-2 and EN 13813, with cleanroom particle/VOC testing and indirect food-contact suitability
- Strong adhesion (>1.5 N/mm2) to correctly prepared concrete and cementitious screeds
- Can be finished smooth-gloss or, with aggregate broadcast, as a slip-resistant surface
- Suitable for both interior and sheltered exterior use across a wide 10-30 C application window
Limitations & considerations
- Bridges only fine, essentially static hairline cracks — it is not a joint sealant and will not span live, moving or structural joints
- Application window is 10-30 C for product, air and substrate; pot life collapses to about 10 minutes at 30 C, leaving little working time
- Requires substrate moisture below ~4% (CM method) and no rising damp; unforgiving of wet or vapour-driven slabs
- Relative humidity must stay below 80% and the surface must be kept clear of condensation for the first 24 hours
- Like all epoxies it can chalk, gloss-off and shift shade under prolonged direct UV, so it is not ideal for fully open outdoor areas
- Colour consistency depends on using matched batch numbers across a continuous area
Selection & best practice
Success is decided before the resin is opened. Prepare the concrete by shot-blasting or grinding to a sound, laitance-free profile, confirm at least 25 N/mm2 compressive and 1.5 N/mm2 tensile strength, and check moisture is under 4% by the CM method with no rising damp. Always prime with the appropriate Sika epoxy primer and fill blowholes so the elastic layer bonds and does not pinhole. Work strictly inside the 10-30 C band and keep the substrate at least 3 C above dew point — plan around the pot life, which is only about 30 minutes at 20 C and far shorter when it is hot, so mix in manageable batches. Combine Part A and Part B mechanically for about 3 minutes, then decant into a clean container and remix to avoid unmixed streaks on the wall of the pail. Apply the wearing layer at roughly 1.6 kg/m2 per mm; for slip resistance, broadcast aggregate into the wet coat and lock it in with a seal coat at about 0.75-0.85 kg/m2. Respect the overcoating window (roughly 30-48 hours at 20 C) and protect the fresh floor from moisture and condensation for the first 24 hours. Allow light traffic at around 4 days and hold heavy loading and chemical exposure until full cure near 7-10 days at 20-30 C.
Specifications
| Chemical base | Two-component, solvent-free tough-elastic epoxy resin |
| Mixing ratio (A:B) | 85:15 by weight |
| Solid content | ~100% by weight and volume |
| Mixed density | ~1.6 kg/L |
| Wearing-layer consumption | ~1.6 kg/m2 per mm thickness |
| Seal / top coat consumption | ~0.75-0.85 kg/m2 |
| Shore D hardness | ~60 (14 days at 23 C) |
| Crack bridging | ~0.2 mm (ZG DIBt) |
| Tensile adhesion | >1.5 N/mm2 |
| Pot life | ~60 min at 10 C / ~30 min at 20 C / ~10 min at 30 C |
| Pack size | 25 kg ready-to-mix unit (Part A 21.25 kg + Part B 3.75 kg) |
| Standards | EN 1504-2, EN 13813; ZG DIBt approval |
Industry use cases
Food & Beverage Processing
Dairies, breweries and bottling halls get a seamless, indirect food-contact surface that resists cleaning chemicals and bridges the fine slab cracks that would otherwise trap bacteria.
Chemical Manufacturing
Handling and reactor areas gain defined chemical resistance plus an easily decontaminated, joint-free skin over slabs that inevitably develop shrinkage cracking.
Warehousing & Logistics
Storage and picking floors take foot and light wheeled traffic on an abrasion-resistant coating that keeps looking continuous despite hairline movement in large-pour slabs.
Cleanroom-Adjacent & Pharma
Support and gowning spaces use its low particle and VOC emission testing to hold a hygienic, wipe-clean finish where a rigid coating would craze.
Engineering Workshops
Machine shops and maintenance bays get a tough-elastic surface that shrugs off dropped tools, oil spillage and abrasion better than a brittle high-build epoxy.
Frequently asked questions
How is Sikafloor-390 N different from a normal industrial epoxy floor coating?
Will it bridge my expansion or control joints?
How much material do I need per square metre?
Can it be used outdoors?
What surface prep and moisture limits apply?
What is the pot life and how long before I can use the floor?
How we position Sika Sikafloor-390 N
Within the Sika flooring family, Sikafloor-390 N is the crack-tolerant workhorse. It needs a Sika epoxy primer (such as Sikafloor-161) under it, and where you want the same tough-elastic performance with quicker turnaround or a self-smoothing feel you can look across the wider Sikafloor range. If a project actually needs full flexibility over a live-moving substrate, a Sikafloor PU or Sikalastic deck-coating system is the honest choice rather than pushing 390 N past its 0.2 mm crack-bridging envelope. Where the slab is sound and crack-free and the priority is pure chemical and abrasion resistance rather than elasticity, a rigid solvent-free epoxy will be more economical. From our other brands, we can also specify Fosroc Nitoflor and MC-Bauchemie flooring lines for comparable industrial duty. As an authorised distributor and applicator across Delhi NCR and pan-India, Space Arc can help you choose the right build-up, prime correctly and apply within the temperature and moisture window that these coatings demand.
Fosroc Nitoflor FC150 — Choose FC150 when the slab is sound and crack-free and you need a robust, high-build solvent-free epoxy purely for chemical and abrasion resistance, without paying for the tough-elastic crack-bridging that sets the 390 N apart.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.