Sika Sikafloor-81 EpoCem
Three-part epoxy-cement self-smoothing screed and temporary moisture barrier that lets you coat resin floors over green or damp concrete, applied 1.5 to 3 mm thick.
What is it?
A three-part, epoxy-modified cementitious screed from Sika that combines epoxy resin, a curing agent and a graded cement-aggregate powder into a fine-textured, self-smoothing mortar laid at 1.5 to 3 mm.
Where is it used?
Interior industrial and hygienic floors where the slab is still green or holds high moisture, ahead of epoxy, polyurethane or PMMA resin systems in food, dairy, beverage, pharma and warehouse projects.
Why use it?
It stops osmotic blistering by acting as a temporary moisture barrier, so resin toppings can go down weeks earlier than a fully dried slab would normally allow, compressing the programme.
How is it applied?
Force-mixed with a double-paddle mixer, poured onto a prepared, mechanically abraded substrate, spread with a smoothing trowel and de-aerated with a spiked roller, then overcoated once tack-free.
About Sika Sikafloor-81 EpoCem
Sikafloor-81 EpoCem sits in an unusual niche in the flooring world: it behaves like a cementitious screed while carrying the moisture tolerance and chemical resilience of an epoxy. Structurally it is a hybrid, three-part system. Part A is the epoxy resin, Part B the hardener, and Part C a pre-batched blend of cement and graded aggregate. Combined at the factory-set ratio, they cure into a dense, fine-textured mortar that you trowel and roller out to a self-smoothing 1.5 to 3 mm layer. Because the cement phase tolerates water in the substrate, the product bonds happily to green or damp concrete without the standing water and osmotic problems that would wreck a straight epoxy screed on the same slab.\n\nFor Indian contractors and consultants, its real value is time. Conventional resin floors demand a slab dried to roughly 4% surface moisture, which on a fresh pour can mean waiting many weeks. Laid at a minimum of 2 mm, Sikafloor-81 EpoCem works as a temporary moisture barrier (TMB) that holds back residual dampness, letting the specified epoxy or PU topping follow within days rather than after a long drying stand-down. Space Arc Engineering supplies and applies it as an authorised Sika distributor across Delhi NCR and pan-India, typically where a food, pharma or warehouse project is fighting a tight handover date on concrete that simply has not had time to dry.
The technical insight
The mechanism that makes this product work is water vapour management, not water blocking. A pure epoxy laid on damp concrete traps rising moisture; vapour pressure builds beneath the impermeable film and lifts it off as osmotic blisters. Sikafloor-81 EpoCem is deliberately engineered the other way: it is impermeable to liquid water yet has good water vapour permeability, with a documented vapour diffusion resistance (µ) of 252 and an equivalent air-layer depth of just 0.75 m at 3 mm. In practice the screed lets vapour breathe upward and dissipate rather than accumulate, so the subsequent resin coat is protected from blistering. The epoxy modification also gives the cement matrix a thermal expansion coefficient close to concrete (about 15.2 x 10-6 per K), so the screed and slab move together instead of debonding under temperature swings. Mechanically it develops fast, reaching around 50 N/mm2 compressive strength at 7 days and 60 N/mm2 at 28 days, which is why it qualifies as an EN 1504-3 Class R4 structural repair material and can serve as a wearing screed in its own right.
Where it is used
- Temporary moisture barrier under epoxy, PU or PMMA resin floors laid over green or damp concrete
- Levelling layer beneath Sikafloor resin systems and sheet floor coverings
- Self-smoothing wearing screed for interior areas with no aesthetic requirement
- Patch repair and resurfacing of worn or spalled horizontal concrete, bulked with quartz sand for greater depths
- Fast-track flooring in dairies, breweries and beverage plants on freshly poured slabs
- Hygienic sub-floors in pharmaceutical, cleanroom and healthcare refurbishments
- Levelling and moisture control in commercial kitchens and food-processing halls
- Warehouse and logistics slab preparation ahead of resin coating on a compressed programme
Key advantages
- Bonds to green or damp concrete, removing the long drying wait before resin flooring can start
- Acts as a temporary moisture barrier that prevents osmotic blistering of the finished resin coat
- Overcoatable with resin floors after about 24 hours at +20 C, keeping the programme moving
- Good water vapour permeability lets residual moisture breathe out instead of building pressure
- High early and ultimate strength, reaching roughly 60 N/mm2 compressive at 28 days
- Classified R4 under EN 1504-3, so it doubles as a structural concrete repair mortar
- Thermal expansion close to concrete, giving reliable adhesion under temperature change
- Impermeable to liquids with good resistance to water, oils and specific chemicals; will not corrode reinforcement
Limitations & considerations
- Interior use only; it is not designed for exposed external floors or UV-driven applications
- Pot life is short and drops sharply with heat, from about 40 minutes at +10 C to 20 at +20 C and only 10 at +30 C, so batch sizes must match the crew
- As a TMB it manages moisture temporarily, not permanently; the substrate should still be trending towards a stable moisture state
- Application window is limited to +8 C to +30 C with relative humidity between 20 and 80%
- No water may be added to the mix and free-fall mixers must not be used, so proper forced-action equipment is essential
- Sika specifies application by approved, experienced applicators; it is unforgiving of poor substrate preparation
Selection & best practice
Success depends on the substrate and the discipline of mixing. Mechanically prepare the concrete by abrasive blasting, planing or scarifying to remove laitance, open blow holes and expose sound aggregate, then vacuum away all dust. There must be no standing water, and on very fresh pours allow at least three days for early shrinkage before screeding so shrinkage cracks do not telegraph through. Force-mix Part A, then Part B, then the full Part C powder with a double-paddle mixer above 700 W at 300 to 400 rpm; never add water and never over-mix, which entrains air. Work to the pot life for the day’s temperature and lay in continuous panels, de-aerating with a spiked roller. For a temporary moisture barrier keep the layer to a minimum of 2 mm. Vapour-permeable seal coats can follow once the surface is tack-free; for vapour-tight resin systems wait until surface moisture falls below 4%, which at +20 C is roughly one day.
Specifications
| Chemical base | Three-part epoxy-cement hybrid (Part A resin, Part B hardener, Part C cement-aggregate powder) |
| Mixing ratio (by weight) | A : B : C = 1 : 2.5 : 17 at +12 C to +25 C |
| Layer thickness | 1.5 to 3 mm as screed; minimum 2 mm as temporary moisture barrier |
| Consumption | 2.25 kg/m2 per mm of thickness (4.5 kg/m2 at 2 mm minimum TMB) |
| Compressive strength (EN 13892-2) | ~50 N/mm2 at 7 days; ~60 N/mm2 at 28 days |
| Flexural strength (EN 13892-2) | ~11 N/mm2 at 7 days; ~14 N/mm2 at 28 days |
| Pot life | ~40 min at +10 C, ~20 min at +20 C, ~10 min at +30 C |
| Packaging | Pre-batched 23 kg unit (Part A 1.14 kg, Part B 2.86 kg, Part C 19 kg) |
| Standards / cured colour | EN 1504-3 Class R4, CE per EN 1504-2 and EN 13813; light grey matt finish |
Industry use cases
Dairy & Beverage Plants
Laid as a temporary moisture barrier on freshly cast slabs so hygienic epoxy or PU floors can be installed within days instead of waiting weeks for the concrete to dry.
Pharmaceutical & Cleanrooms
Provides a smooth, moisture-controlled levelling base under seamless resin systems in refurbishment work where downtime must be minimised.
Warehousing & Logistics
Fast-track levelling and moisture management of large slab areas ahead of resin coating, keeping fit-out programmes on schedule.
Commercial Kitchens
Screeds and levels damp interior slabs before hygienic toppings in food-service floors that cannot tolerate blistering from trapped moisture.
Concrete Repair
Bulked with quartz sand and used as an R4 patch-repair mortar to reinstate worn or spalled horizontal concrete before overcoating.
Frequently asked questions
Can Sikafloor-81 EpoCem really be applied over green or damp concrete?
How does it work as a temporary moisture barrier?
How soon can I apply the resin topping over it?
Is it suitable for outdoor floors?
What is the pot life and why does it matter?
Can it be used as a structural repair mortar?
How we position Sika Sikafloor-81 EpoCem
Within the Sika range, Sikafloor-81 EpoCem is the workhorse of the EpoCem family and is usually specified alongside its companions: prime green or absorbent substrates with Sikafloor-81 EpoCem’s related primer, step up to Sikafloor-82 EpoCem where a thicker or more robust levelling layer is needed, and follow with a Sikafloor MultiDur or PurCem resin topping as the finished wearing surface. Where the brief calls for a self-levelling epoxy that both tolerates damp concrete and serves as the visible floor in one operation, our Fosroc line offers a direct alternative in Nitoflor SL2050. Across our other brands, contractors chasing the fastest turnaround on damp slabs sometimes pair it with MC-Bauchemie or Dr. Fixit moisture-management systems; our technical team can match the right build-up to the substrate and the programme.
Fosroc Nitoflor SL2050 — Specify this when the client wants a single damp-tolerant, self-levelling epoxy topping that is also the finished floor, rather than an EpoCem barrier laid under a separate resin system.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.