Fortis 823 Prime is a fast-curing, two-component epoxy primer designed to penetrate and seal prepared concrete before applying epoxy floor coatings. Its low-viscosity formulation promotes excellent adhesion, with typical coverage of 8–14 m²/L and a recoat time of 3–4 hours. Ideal for industrial, commercial and decorative epoxy flooring systems.
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Fortis 823 Prime is a fast-curing, solvent-based epoxy primer formulated to penetrate concrete, seal porous surfaces and provide a strong bonding layer for subsequent epoxy floor coatings.
Its low-viscosity formulation improves substrate wetting and helps achieve uniform adhesion across prepared concrete. The rapid recoat time makes it particularly suitable for industrial, commercial and decorative flooring projects requiring faster turnaround.
823 Prime is suitable beneath Fortis Coat 823 HS and compatible epoxy flooring systems, including decorative flake finishes. It may also be applied as a two-coat system for sealing and dust-proofing suitable interior concrete floors.
For alternative substrate conditions, consider Fortis 820 Prime or HydroFort Epoxy Vapour Barrier where appropriate.
Refer to the Technical Data Sheet for detailed application requirements.
Two-Component Solvent-Based Epoxy Primer
FORTIS 823 Prime is a fast-curing, solvent-based epoxy primer for warehouses, factories, workshops, garages and commercial concrete floors. It is particularly suitable beneath high-build epoxy coatings and decorative flake systems where rapid recoating is required.
Apply to clean, sound and mechanically prepared concrete. Diamond grinding is recommended to remove laitance, contamination and weak surface material while providing a suitable profile for adhesion.
Premix Parts A and B separately. Combine 1 part resin (Part A) with 1 part hardener (Part B) by volume. Mix at low speed for approximately one minute, allow to stand for one minute, then mix for a further minute until homogeneous.
Mix only enough material for immediate use. Pour onto the prepared concrete in ribbons and distribute evenly using a 5–8 mm nap microfibre roller. Suitable airless spray equipment may also be used where specified.
Highly porous concrete may require additional wet-on-wet application to achieve uniform priming. Follow the current Technical Data Sheet for coverage, pot life and recoating requirements.
Complete Your Flooring System: Apply a compatible topcoat such as FORTIS Coat 823 HS. For poor, difficult or suitably prepared slightly damp concrete, consider FORTIS 820 Prime instead.
For guidance on selecting the correct primer, read How to Choose an Epoxy Floor Primer.
Suitable Surfaces
Fortis 823 Prime is suitable for mechanically prepared concrete, porous cementitious substrates and compatible existing coating systems requiring a penetrating epoxy primer before subsequent flooring.
Concrete must be clean, sound and free from dust, laitance, loose material, oil, grease, curing compounds and other contaminants that may affect adhesion. Diamond grinding is the preferred preparation method because it removes weak surface material and provides a suitable profile for coating adhesion.
New concrete should normally be cured for at least 28 days before coating.
Existing compatible coatings must be firmly bonded, cleaned and mechanically abraded. Test adhesion on a small area before proceeding.
For poor, difficult or suitably prepared slightly damp concrete, Fortis 820 Prime may be more appropriate. Where rising damp or significant moisture transmission is present, investigate the substrate and use an appropriate HydroFort™ epoxy vapour barrier where required.
8 L and 40 L kits
823 Prime is a fast-curing epoxy primer with a typical recoat time of 3–4 hours. Follow the current Technical Data Sheet for temperature conditions and the maximum recoat window.
823 Prime is designed for fast curing and recoating on sound, dry concrete. 820 Prime is preferred for poor, difficult or suitably prepared slightly damp concrete where high adhesion and substrate consolidation are priorities.
Yes. 823 Prime is suitable beneath FORTIS Coat 823 HS and compatible decorative flake flooring systems where rapid recoating is required.
823 Prime is intended for dry, properly prepared concrete. For slightly damp or difficult substrates, consider 820 Prime. Significant moisture transmission requires separate assessment and may require a vapour barrier.
Typical coverage is 8–14 m²/L, depending on concrete porosity, surface profile and application method. Highly porous concrete may require additional material.
Mix 1 part resin (Part A) with 1 part hardener (Part B) by volume. Use a low-speed mechanical mixer and follow the current Technical Data Sheet.
Highly porous concrete may require additional wet-on-wet application to achieve uniform priming and avoid uneven absorption.
Fortis 823 Prime Technical Data Sheet
Fortis 823 Prime Light Grey Technical Data Sheet
Fortis 823 Prime Part A Safety Data Sheet
Fortis 823 Prime Part B Safety Data Sheet
Fortis 823 Prime Light Grey Part A SDS
Fortis 823 Prime Light Grey Part B SDS
How to Choose an Epoxy Floor Primer
