Sika Sikafloor-80 EpoCem Primer
The water-based epoxy tie-coat that lets the Sika EpoCem system grip young, damp concrete no solvent smell, no long drying wait.
What is it?
A two-component, water-based epoxy resin primer and adhesion promoter that keys the Sikafloor EpoCem levelling range onto concrete, screeds and existing EpoCem layers.
Where is it used?
On new or old concrete and cementitious screeds ahead of Sikafloor-81 or -82 EpoCem, including matt-damp slabs that are still releasing moisture.
Why use it?
It builds a reliable, high-strength bond (over 1.5 N/mm2) on absorbent and freshly cured substrates where solvent primers cannot be trusted, and it does so odour-free for occupied and enclosed spaces.
How is it applied?
Mixed 1:2.5 by weight, then rolled or brushed at 0.25 to 0.4 kg/m2 per coat in one or two coats, and overcoated with the EpoCem screed within the stated window while the film is still fresh.
About Sika Sikafloor-80 EpoCem Primer
Sikafloor-80 EpoCem Primer sits at the very first step of the Sika EpoCem flooring build-up, and its job is deceptively simple: make sure the epoxy-cement levelling layer that follows actually stays stuck. It is a two-component, water-based epoxy resin supplied as a white Part A and a translucent yellowish Part B that combine into a yellowish mixed liquid. Because the carrier is water rather than solvent, it wets into the open pores of concrete instead of skinning over the top, and it can be applied on green or matt-damp slabs the exact conditions that defeat conventional solvented primers. For Indian sites racing against monsoon humidity and tight handover dates, that tolerance for residual moisture is the whole point.
In practice the primer is the bridge between the raw substrate and the Sikafloor-81 or Sikafloor-82 EpoCem levelling screeds. Applied on new or old concrete, on cementitious screeds, or as a refresh coat over an earlier EpoCem layer, it neutralises surface dust, seals absorbency and leaves a receptive film for the screed to key into. It is deliberately a system component rather than a standalone floor: on its own it is a thin bond coat, not a wearing surface or a permanent damp-proof membrane. Used correctly within the EpoCem sequence, though, it is what lets contractors install resin-compatible finishes over concrete that would otherwise need weeks of extra drying time.
The technical insight
The mechanism is about penetration and cross-linking, not surface tack. A solvent-borne epoxy on a damp slab is fighting physics water and solvent do not mix, so the film beads, traps moisture and delaminates. Sikafloor-80 is water-based, so its emulsion is compatible with the moisture already in the pores; it soaks in, then the epoxy phase coalesces and cures as the water leaves, locking a resin skeleton into the concrete rather than laying on top of it. That is why the tensile adhesion measured to ISO 4624 exceeds 1.5 N/mm2, typically forcing failure into the concrete itself rather than at the glue line. The 1:2.5 Part A to Part B ratio by weight is chemistry, not a suggestion off-ratio mixing starves the cross-link and leaves a soft, under-cured film so the pre-batched units are meant to be used whole. Pot life is temperature-driven (around 120 minutes at 10 C, 90 at 20 C, 45 at 30 C), and the overcoat window works the same way: the EpoCem screed must go on while the primer is still chemically open (12 to 24 hours at 10 C, 6 to 12 at 20 C, 4 to 6 at 30 C) so the two layers co-cure into one monolithic bond.
Where it is used
- Priming new or freshly cured concrete before Sikafloor-81 or Sikafloor-82 EpoCem levelling layers
- Bonding EpoCem screeds onto matt-damp slabs that are still releasing residual construction moisture
- Sealing and dust-binding highly absorbent, porous concrete floors ahead of a resin-cement build-up
- Re-priming an existing or aged Sikafloor EpoCem layer before a fresh overlay
- Floor preparation in food, beverage and pharmaceutical plants where solvent odour is unacceptable
- Warehouse, factory and logistics floors on fast-track programmes with limited slab drying time
- Enclosed and occupied areas such as basements, service corridors and plant rooms needing low-odour work
- Refurbishment of process and utility floors where the substrate cannot be fully dried before recoating
Key advantages
- Bonds to green and matt-damp concrete, cutting the wait for slabs to dry fully
- Water-based and virtually odourless, so it suits occupied, enclosed and food-grade areas
- High tensile adhesion above 1.5 N/mm2 to ISO 4624, generally failing in the concrete not the bond
- Penetrates and seals highly absorbent, dusty substrates for a receptive, unified surface
- Fast, low-fuss application by roller or brush with straightforward one- or two-coat coverage
- Pre-batched Part A and Part B units keep the critical 1:2.5 ratio right on site
- Integral part of the proven Sika EpoCem moisture-tolerant flooring system
- Reasonable working time on cool and moderate days for comfortable placing
Limitations & considerations
- It is a bond coat within the EpoCem system, not a standalone floor finish or wearing surface
- Not a permanent structural damp-proof membrane; it works as a temporary moisture-tolerant tie-coat under the EpoCem build-up
- Must be overcoated with Sikafloor-81 or -82 EpoCem inside the stated window or the bond weakens
- Application is limited to +10 C to +35 C and up to 85% relative humidity
- Pot life shortens sharply in heat (about 45 minutes at 30 C), so batches must be sized to the crew
- Off-ratio or hand-guessed mixing leaves a soft, under-cured film use full pre-batched units
Selection & best practice
Prepare the substrate mechanically grind or shot-blast to a sound, open, laitance-free surface and remove loose dust; standing water must be cleared, though a matt-damp surface is acceptable for EpoCem overcoating. Add the whole of Part B to the whole of Part A and mix with a slow-speed drill and paddle to a uniform, streak-free liquid; never split a unit or adjust the 1:2.5 ratio. Apply evenly by roller or brush at 0.25 to 0.4 kg/m2 per coat, giving highly porous floors a second coat so no dry, unsealed patches remain. Work within the pot life for the day’s temperature and mix only what the team can lay down in time. Then place the Sikafloor-81 or -82 EpoCem screed within the overcoat window for the site temperature (roughly 6 to 12 hours at 20 C) so the layers co-cure. Keep application and substrate between +10 C and +35 C and below 85% RH, and always confirm current figures against the latest Sika Product Data Sheet for the batch supplied.
Specifications
| Product type | Two-component, water-based epoxy resin primer / adhesion promoter |
| Colour | Part A white, Part B translucent yellowish; mixed yellowish liquid |
| Mixing ratio (A:B) | 1 : 2.5 by weight |
| Consumption | 0.25 to 0.4 kg/m2 per coat, applied in 1 to 2 coats (substrate-dependent) |
| Pot life | Approx. 120 min at +10 C, 90 min at +20 C, 45 min at +30 C |
| Overcoat waiting time (before EpoCem) | 12 to 24 h at +10 C, 6 to 12 h at +20 C, 4 to 6 h at +30 C |
| Tensile adhesion strength | > 1.5 N/mm2 (ISO 4624) |
| Application / substrate temperature | +10 C minimum to +35 C maximum; max 85% relative humidity |
| Mixed density | Approx. 1.05 kg/l at +27 C |
Industry use cases
Food, Beverage and Pharma
Priming process-area slabs ahead of the EpoCem screed where solvent odour, taint and downtime are unacceptable and hygiene finishes must go down fast.
Warehousing and Logistics
Getting large, freshly cast floors ready for resin-cement levelling on tight fit-out programmes without waiting weeks for the slab to reach full dryness.
Manufacturing and Heavy Industry
Bonding EpoCem build-ups onto absorbent or moisture-laden factory floors in plant rooms, workshops and production halls.
Basements and Enclosed Services
Low-odour priming in poorly ventilated basements, service corridors and utility rooms where water-based chemistry keeps the space workable.
Refurbishment and Repair
Re-priming aged or damp existing floors, or an earlier EpoCem layer, so a fresh moisture-tolerant overlay keys down reliably.
Frequently asked questions
Can Sikafloor-80 EpoCem Primer be applied on damp concrete?
Is this primer a floor finish on its own?
What is the mixing ratio and can I mix part of a unit?
How much primer will I need per square metre?
How long before I can lay the EpoCem screed on top?
Does it act as a permanent damp-proof membrane?
How we position Sika Sikafloor-80 EpoCem Primer
Sikafloor-80 EpoCem Primer is only the first coat of a system, so specify it alongside the layers it feeds: Sikafloor-81 EpoCem for a thin self-smoothing moisture-tolerant screed and Sikafloor-82 EpoCem where a thicker levelling mortar is needed. Above the EpoCem base, most projects finish with a Sika resin floor such as the Sikafloor epoxy or polyurethane topcoats, and joints or fillets are detailed with Sikadur or Sikaflex products keeping the whole build-up within one warranted Sika family. If a project is running a Fosroc-based flooring specification instead, the equivalent priming step is Fosroc Nitoprime 25, a two-part epoxy primer that keys concrete for Nitoflor toppings; note it is solvent-containing, so a specifier would choose it inside a Fosroc system, whereas the water-based Sika primer is the better fit where odour-free work or a damper slab is the deciding factor. Talk to Space Arc for the right primer-to-topcoat combination for your slab condition and finish.
Fosroc Nitoprime 25 — A specifier already building on a Fosroc flooring specification would choose Nitoprime 25 as the epoxy priming step for Nitoflor toppings, though it is solvent-containing rather than water-based like the Sika primer.
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