Megapoxy 154

For treating damp surfaces, masonry, and green concrete, Megapoxy 154 is a two-component water-based epoxy designed to prime, seal, and provide a moisture barrier before laying down floor finishes or secondary membranes. It cures to a matte, chemical-resistant coating that tolerates foot traffic and light vehicular traffic in large commercial spaces like car parks and warehouses.

What it does

Megapoxy 154 combines epoxy adhesion with the practical application benefits of a water carrier, allowing it to penetrate and bond directly to damp concrete substrates. The mixed formula acts as a concrete curing membrane, a dust sealer for interior concrete floors, or a moisture barrier on damp surfaces before installing timber or vinyl overlays. It is also suitable as a primer for acrylic and polyurethane membranes (excluding WBE Clear), ensuring a sound bond key on porous masonry and concrete.

Numbers that matter

• 60-minute work time (at 25°C): Your application window to mix, thin with water if required, and roll or spray the material before it begins to set.
• 140–180 minutes thin film cure (at 25°C): Rapid initial drying phase under standard conditions to minimise downtime between coats.
• 24-hour minimum cure time (at 25°C and 50% RH): The compulsory drying window required before applying subsequent waterproof membranes, adhesives, mortars, decorative coatings, or top treatments.
• 5 to 8 sqm per litre coverage: Application rate per coat for a smooth finish when applied by brush, roller, or airless spray.
• 10°C minimum application temperature: The lower limit for the substrate and ambient air; application below this point dramatically slows curing and can cause amine blush.

Where to use it

• Green concrete and damp surfaces: Prime and seal damp masonry where standard solvent-borne epoxies cannot bond.
• Slab preparation: Seal concrete slabs to control moisture vapour before laying down vinyl and timber overlays.
• Trafficable floors: Dust-seal interior concrete floors in high-traffic zones exposed to oil, grease, chemicals, and light vehicles.
• Membrane priming: Apply as a preparatory primer under acrylic and polyurethane waterproofing membranes.

Limitations

• Not a standalone waterproofing membrane: Megapoxy 154 is a barrier and primer, not a flexible waterproof membrane. Use a dedicated waterproofing membrane where water exclusion is required.
• Rigid cure: Once cured, the epoxy is rigid and will not absorb or bridge movement cracks.
• UV exposure: Megapoxy 154 will tend to chalk and yellow when exposed to UV light. For external applications, apply a UV-resistant top coat.
• Substrate compatibility: Do not apply over surfaces previously treated with curing compounds, PVA concrete bonding agents, or acrylic coatings. Mechanically clean these back to bare concrete first.
• No metal application: Do not apply to steel or metal surfaces, as corrosion will occur.
• No cement mixing: Do not add cementitious products directly to Megapoxy 154.
• Humidity and cold limits: Curing is dramatically slowed if relative humidity exceeds 80% or if temperatures fall below 10°C. In cool conditions, substrate temperatures can produce an oily amine blush or tacky discolouration, which must be fully removed before applying subsequent coats.

How to apply

All surfaces must be structurally sound and clean of previous coatings, adhesives, efflorescence, laitance, grease, and oil by grinding, shot blasting, high-pressure water washing, or mechanical scrubbing. Repair all holes and non-structural cracks with suitable Megapoxy repair compounds before priming.

Mix 1 Part A to 1 Part B by volume in a clean mixing vessel for a minimum of 3 minutes. If thinning, up to 25% water may be added and mixed until completely homogeneous after the resin and hardener are fully mixed. Do not mix Part A, Part B, and water at the same time. In cold temperatures, mix for at least 1 extra minute and let the mixed batch stand for 5 minutes to accelerate drying. For best results, store the kit at 20°C for 24 hours prior to mixing.

Megapoxy 154 requires a minimum of two coats, applied with a brush or roller at right angles to the previous coat to fill voids and eliminate pinholes. Test the wet film depth at random points during application with a wet film gauge. For porous concrete, a third coat may be required. For non-slip finishes, mix a fine epoxy-grade sand aggregate directly into the wet mix, or broadcast coarser aggregate directly into the first wet coat and seal with subsequent coats. Clean all mixing tools and equipment with Megapoxy Thinners immediately after use.