Everflex Multi-Prime Acrylic Primer

For prep work on substrates with varying absorption rates, Everflex Multi-Prime Acrylic Primer is a single-part, water-based acrylic primer that stabilises both porous and non-porous surfaces. It is formulated to prepare substrates for the application of Everflex waterproofing membranes, self-levelling compounds, cement-based ceramic tile adhesives, and grouts in both internal and external environments.

How it works

Everflex Multi-Prime functions as an adhesion promoter and surface sealer. It dries to a tack-free, translucent green film that indicates uniform coverage. The solvent-free, low-VOC formula is non-corrosive and contains active agents that inhibit mould, mildew, and biological growth in hot and humid environments. It can be applied neat on non-porous substrates to form a bonding bridge, or diluted with water to penetrate and control the absorption of porous substrates, preventing the rapid loss of water from subsequent levelers or adhesives.

Numbers that matter

• 1 hour cure time (at 23°C): Standard drying window required to achieve a tack-free, translucent film before applying subsequent coatings or compounds.
• 5 to 10m² per litre coverage: Standard application yield, which varies within this range depending on the porosity of the target substrate.
• 10°C to 35°C application range: The acceptable ambient and substrate temperature window for safe application and film formation.

Where to use it

The primer is compatible with a wide range of structural and finishing substrates, provided they are clean and dry:

• Concrete (cured for at least 28 days) and pre-cast concrete (with release agents removed).
• 3:1 sand cement screeds, C-Bed, and masonry or render (cured for at least 4 days).
• Cement sheeting, underlay, external weatherboard, and blue board.
• Wet area plasterboard and Villaboard.
• Timber flooring, including structural plywood Type A (PAA JAS-ANZ).
• Brickwork and Hebel aggregate blocks.
• Water-based painted surfaces, some plastics, ceramic tiles, and burnished concrete.

Limitations

• Do not apply on ceramic tiles with a high gloss coating.
• Do not apply on damp, wet, or contaminated substrates, if it is raining, or if rain is imminent.
• Not suitable for areas subject to hydrostatic pressure or rising damp; Everflex VBS is recommended for these conditions.
• The primer has limited UV resistance and is not designed for long-term exposure; it must be overcoated.
• Do not use solvents or acid etching to clean the subfloor prior to application.
• Foot traffic limitations apply once the primer is laid.

How to apply

To determine substrate porosity, place a puddle of water the size of a one-dollar coin on the surface. If the water absorbs in less than two minutes, the substrate is porous; if the puddle remains, it is non-porous.

Porous substrates: Dilute 1 part Multi-Prime with 2 parts clean water. Apply by brush, roller, or spray, ensuring the primer remains wet on the surface for 2 minutes to achieve penetration. For exceptionally porous substrates, apply a second coat diluted 1 part primer to 3 parts water, allowing 30 minutes of curing time between coats. Adheseal WBP may be used as an alternative for porous concrete applications.

Non-porous substrates: Apply an even layer of neat, undiluted Multi-Prime using a roller or brush. For extremely non-porous surfaces (such as burnished concrete or ceramic tiles), perform a light grind or sand first to mechanically enhance adhesion.

Clean tools and wet spills immediately with water. Cured material must be removed by mechanical means.