FORTIS 820 Prime is a high-solids, low-solvent epoxy primer with excellent adhesion and penetration into soft, porous and difficult concrete. It helps consolidate suitable weak concrete surfaces and provides a reliable bonding layer for epoxy floor coatings. Also suitable for properly prepared slightly damp concrete.
Information | Applications | Specifications | Downloads | FAQs
FORTIS 820 Prime is a two-component, high-solids, low-solvent epoxy primer developed for excellent adhesion to concrete and other compatible mineral substrates. Its outstanding substrate wetting and penetration make it particularly effective on soft, porous or difficult concrete where conventional primers may not provide sufficient consolidation.
820 Prime penetrates suitable porous concrete, helping bind the surface and create a strong bonding layer for subsequent epoxy floor coatings. It is particularly useful for older industrial floors, workshops, warehouses and concrete with poor surface integrity.
The formulation offers good low-temperature curing performance, blush resistance and suitability for properly prepared slightly damp concrete without standing water. Loose or structurally unsound concrete must still be removed or repaired before application.
820 Prime can be used beneath FORTIS Coat 823 HS and FORTIS Coat 824 SL. It may also be used as a clear sealer and dust-proofer on suitable concrete.
For rapid recoating on sound, dry concrete, consider FORTIS 823 Prime. Where significant moisture vapour transmission is present, an appropriate moisture-control system such as HydroFort VB should be assessed.
High-Solids, Low-Solvent Two-Component Epoxy Primer
Typical Applications: FORTIS 820 Prime is used beneath epoxy floor coatings in warehouses, factories, workshops, garages and commercial premises. It is especially suitable for soft, porous or difficult concrete requiring improved surface consolidation and adhesion.
Surface Preparation: Concrete must be clean and free from laitance, loose material, dust, oil, grease and curing compounds. Diamond grinding is recommended to remove weak surface material and provide a suitable profile. Repair structurally unsound concrete before priming. New concrete must be cured for at least 28 days.
Mixing: Premix Parts A and B separately. Combine 4 parts 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 remix for a further minute until homogeneous.
Application: Apply by brush, roller or broom. Pour mixed material onto the floor in ribbons and distribute evenly using a suitable microfibre roller. Highly porous concrete may require additional wet-on-wet application to achieve uniform priming.
Typical coverage is approximately 6 m²/L, with an 8–48 hour recoat window. Follow the current Technical Data Sheet for application conditions and working time.
Complete Your System: Apply a compatible topcoat such as Coat 823 HS or Coat 824 SL. For primer selection advice, see How to Choose an Epoxy Floor Primer.
FORTIS 820 Prime is suitable for mechanically prepared concrete, porous mineral substrates and compatible surfaces requiring high adhesion and excellent substrate wetting.
It is particularly effective on suitable soft, porous or difficult concrete where penetration and consolidation are required. The surface must remain sufficiently sound to support the coating system.
820 Prime may be applied to properly prepared slightly damp concrete without standing water. It is not designed to control rising damp, hydrostatic pressure or significant moisture vapour transmission.
Existing coatings must be assessed for compatibility and adhesion before recoating. Follow the current Technical Data Sheet for surface preparation and substrate requirements.
5 L kit
Yes. Its excellent wetting and penetration help consolidate suitable soft or porous concrete and improve adhesion before epoxy flooring. Loose or structurally unsound concrete must first be repaired.
No. 820 Prime is a high-solids, low-solvent epoxy primer. It should not be described as solvent-free or zero VOC.
820 Prime is preferred for soft, porous or difficult concrete. 823 Prime is designed for fast recoating on sound, dry concrete.
It can be used on properly prepared slightly damp concrete without standing water. It is not a vapour barrier and should not be used to control significant moisture transmission.
Typical coverage is approximately 6 m²/L. Porous concrete may require additional wet-on-wet application.
Compatible epoxy flooring systems include Coat 823 HS and Coat 824 SL.
The typical recoat window is 8–48 hours, subject to application conditions and the current Technical Data Sheet.
Fortis 820 Prime Technical Data Sheet
Fortis 820 Prime Part A - Safety Data Sheet
Fortis 820 Prime Part B - Safety Data Sheet
How to Prepare Concrete for Floor Coatings and Polishing
How Temperature Affects Floor Coating Application
Why Does Floor Coating Reject or Form Fish Eyes?
Why Does Epoxy Flooring Delaminate?
