Fosroc Dekguard EP302
Two-component, water-dispersed epoxy resin primer that prepares concrete, masonry and steel for the Dekguard PU protective coating system.
What is it?
A two-component, water-dispersed epoxy resin primer supplied in pre-weighed packs that cures to a hard, semi-matt sealing film as the bonding coat beneath the Fosroc Dekguard PU protective coating system.
Where is it used?
On prepared concrete, masonry and steel substrates that will receive Dekguard PU on sewage and effluent works, chemical-processing plants, jetties, car parks, walkways, bridges and other structures in aggressive or marine environments.
Why use it?
It locks down a dust-proof, easily cleaned surface and develops strong adhesion to old and new concrete, ensuring the Dekguard PU topcoat keys reliably while keeping site odour low and clean-up to plain water.
How is it applied?
Stir each component, combine the full base into the hardener and power-mix at least 3 minutes, then apply by brush or lambswool roller and allow the film to dry fully before overcoating with Dekguard PU.
About Fosroc Dekguard EP302
Fosroc Dekguard EP302 is the water-based epoxy primer that sits underneath the Dekguard PU protective coating system, one of Fosroc’s established solutions for protecting concrete and steel in aggressive service. On its own EP302 is not a finishing coat or a standalone anti-carbonation barrier; its job is to convert a freshly prepared, often dusty concrete or blasted steel surface into a sound, sealed and well-keyed base so that the Dekguard PU topcoat can develop its full chemical, UV and carbon-dioxide-diffusion resistance.
Supplied as a two-component, pre-weighed pack, EP302 is a water-dispersed epoxy. The base and hardener are mixed on site immediately before use and the cured film forms a hard, semi-matt seal on concrete and other building substrates. Because it is water-based rather than solvent-based, it has a low odour and is comparatively safe to handle, and tools wash out in clean water – a practical advantage on occupied buildings, plant rooms and confined areas where solvent fumes are a concern. Fosroc originally formulated EP302 for hot Middle East conditions, which also makes it well suited to much of the Indian climate.
For contractors and consultants in India, EP302 is best understood as a system component rather than a product bought in isolation. It is specified wherever Dekguard PU is being applied to concrete, masonry or metal that needs priming – on sewage treatment and effluent plants, chemical-processing structures, marine and coastal assets such as jetties, piers and seawater channels, and trafficked surfaces like car-park decks, bridges and pedestrian walkways. The companion Dekguard PU topcoat is a polyurethane coating with a carbon-dioxide diffusion coefficient of not less than 1.0 x 10 to the minus 7 cm squared per second, which is what gives the finished system its anti-carbonation performance; EP302’s contribution is the adhesion and surface integrity that lets that barrier perform over the long term.
The technical insight
Dekguard EP302 is a two-component, water-dispersed (water-based) epoxy resin primer. Its chemistry is the deciding factor for how it is used: because water has to evaporate as the resin cures, the substrate and the weather both matter. The standalone Fosroc datasheet quotes a pot life of 4 hours at 23 degrees C, falling to 2 hours at 35 degrees C, and the entire base must be poured into the hardener and power-mixed for at least 3 minutes. Coverage is given as 10.0 square metres per litre at 100 microns wet film thickness per coat – a theoretical figure that drops in practice with substrate texture and wastage. The Dekguard PU system datasheet describes EP302 applied at 125 to 190 microns WFT, curing to a 50 to 75 micron dry film, which is the band relevant when it is used as the keying primer beneath the PU topcoat. Two limitations are non-negotiable in the field: EP302 must not be applied over substrates that suffer, or are likely to suffer, from rising damp, and the substrate relative humidity should not exceed 75 to 80 percent (measured to BS 8203 Appendix A). Ponding must be avoided during application, because trapped water prevents complete cure. The primer must be allowed to dry fully – typically about 4 hours at 20 degrees C and 2 hours at 35 degrees C – before Dekguard PU is overcoated, and good ventilation and air movement are essential to drive off the water.
Where it is used
- Priming concrete and masonry before the Dekguard PU anti-carbonation and chemical-resistant topcoat
- Priming blast-cleaned steel and metal surfaces (with Nitoprime 25 first on flash-rusting ferrous metals) ahead of Dekguard PU
- Sealing dusty concrete in sewage treatment works and effluent plants prior to protective coating
- Surface preparation for chemical-processing plant floors and structures
- Coastal and marine assets such as jetties, piers, harbours and seawater intake channels
- Car-park decks, bridges and pedestrian walkways receiving a Dekguard PU finish
Key advantages
- Water-based and low-odour, making it safer to use in occupied buildings, plant rooms and confined spaces
- Strong bonding strength to both old and new concrete surfaces
- Tools and equipment clean up with plain water immediately after use
- Non-flammable, reducing fire-handling restrictions on site
- Supplied in pre-weighed two-part packs, removing on-site batching errors
- Cures to a hard, semi-matt, dust-proof and easily cleaned surface
- Versatile across concrete, masonry and steel within one priming system
- Formulated for hot climates, suiting Indian and Middle East site conditions
Limitations & considerations
- Not a standalone or decorative coating – it is a primer for the Dekguard PU system, not a finished anti-carbonation barrier on its own
- Must not be applied over substrates suffering, or likely to suffer, from rising damp
- Substrate relative humidity must not exceed 75 to 80 percent (per BS 8203 Appendix A)
- Needs good drying conditions with ventilation and air movement so the water can fully evaporate before overcoating
- Ponding of the wet material must be avoided, as trapped water prevents complete cure
- Limited pot life – about 4 hours at 23 degrees C and only 2 hours at 35 degrees C
- Requires mechanical surface preparation (captive shot blasting or grinding) to a fine-to-medium sandpaper texture
- Shelf life of 12 months and sensitive to high storage temperatures
Selection & best practice
Mechanically prepare the substrate (captive shot blasting or grinding) to a clean, dense surface with the texture of fine-to-medium sandpaper, removing all laitance, oil and grease first. Confirm the substrate is dry, free of rising damp and below 75 to 80 percent relative humidity before priming. Mix the full base into the hardener and power-mix with a slow-speed drill and Fosroc paddle for at least 3 minutes, then apply EP302 by brush or lambswool roller in a continuous, uniform film without ponding. Respect the pot life, work faster in hot weather, and ensure good ventilation so the water evaporates. Allow the primer to dry completely – roughly 4 hours at 20 degrees C, 2 hours at 35 degrees C – then overcoat with Dekguard PU. On flash-rusting ferrous metal, apply Nitoprime 25 before EP302, and fill surface irregularities in concrete with the appropriate Nitomortar product.
Specifications
| Product type | Two-component, water-dispersed (water-based) epoxy resin primer |
| Role in system | Priming / bonding coat for the Fosroc Dekguard PU protective coating system |
| Suitable substrates | Concrete, masonry and steel |
| Cured film | Hard, semi-matt seal |
| Mixing | Full base into hardener; power-mix at least 3 minutes (slow-speed drill + paddle) |
| Pot life | 4 hours at 23 degrees C; 2 hours at 35 degrees C |
| Coverage (theoretical) | 10.0 m2/litre at 100 microns wet film thickness per coat |
| Film thickness as PU primer | 125 to 190 microns WFT, curing to 50 to 75 microns DFT (per Dekguard PU datasheet) |
| Application method | Brush or lambswool roller |
| Overcoating / drying | Allow to fully dry before Dekguard PU – typically 4 hours at 20 degrees C, 2 hours at 35 degrees C |
| Substrate RH limit | Not greater than 75 to 80 percent (BS 8203 Appendix A) |
| Cleaning | Clean water immediately after use |
| Flammability | Non-flammable |
| Pack size | 4.5 litre packs |
| Shelf life / storage | 12 months in dry conditions, 10 to 30 degrees C, in original unopened packs |
Industry use cases
Water and wastewater
Priming concrete in sewage treatment and effluent plants before the chemical-resistant Dekguard PU coating protects tanks, channels and structures from aggressive effluent.
Marine and coastal infrastructure
Sealing concrete and blasted steel on jetties, piers, harbours and seawater intake channels ahead of a Dekguard PU finish for UV and saline exposure.
Chemical and process industry
Providing a sound, dust-proof key on chemical-processing plant floors and structures so the polyurethane topcoat can resist acids, alkalis and solvents.
Transport and parking structures
Priming car-park decks, bridge elements and pedestrian walkways before Dekguard PU is applied for traffic, UV and weather durability.
Industrial buildings
Low-odour, water-based priming inside occupied plant rooms and enclosed areas where solvent fumes from conventional epoxy primers would be unacceptable.
Frequently asked questions
Is Dekguard EP302 an anti-carbonation coating by itself?
What is the coverage of Dekguard EP302?
Which substrates can EP302 be applied to?
How long before I can overcoat with Dekguard PU?
What pack size does EP302 come in and what is its shelf life?
Can EP302 be used where there is rising damp?
How we position Fosroc Dekguard EP302
Within the Fosroc range, Dekguard EP302 is a dedicated companion primer for the Dekguard PU protective coating system rather than a product specified on its own – if a project calls for Dekguard PU on concrete or steel, EP302 is the priming layer named in the specification. It sits alongside the wider Dekguard family of anti-carbonation and protective coatings (such as Dekguard S and Dekguard Elastic) and is typically used with supporting Fosroc products including Nitoprime 25 on flash-rusting steel and Nitomortar repair mortars for filling concrete defects before coating. Because EP302 is system-specific, the realistic comparison is at the topcoat-system level rather than a like-for-like primer swap: competing protective and anti-carbonation coating systems in the Indian market include Sika (for example Sikagard anti-carbonation coatings with their own epoxy/PU primers), MBS (MYK Arment) protective coating systems, Dr. Fixit (Pidilite) structural protection coatings, and STP / STP Limited’s protective coating ranges. For an authentic, warranty-backed Dekguard PU installation, the correct approach is to use genuine Fosroc EP302 as the primer rather than substituting another manufacturer’s primer beneath a Fosroc topcoat. Space Arc Engineering, as an authorised Fosroc distributor and applicator covering Delhi NCR and pan-India, supplies EP302 as part of the complete Dekguard PU system and can advise on substrate preparation, the right primer choice for concrete versus steel, and where an alternative system may suit a particular budget or exposure.
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