Fosroc Dekguard Standard
A two-part silane-siloxane primer and UV-stable aliphatic acrylic top coat that shields atmospherically exposed reinforced concrete from carbonation, chlorides and weathering, conforming to BS EN 1504-2.
What is it?
A protective and decorative coating system for concrete and masonry, made up of Fosroc Dekguard Primer (a penetrating silane-siloxane) overcoated with Dekguard S, a pigmented single-component aliphatic acrylic top coat that conforms to BS EN 1504-2.
Where is it used?
Atmospherically exposed (non-trafficked) reinforced concrete and masonry such as building facades, columns, beams, soffits, bridges, flyovers, water-retaining and coastal structures, and surfaces repaired with the Fosroc Renderoc system.
Why use it?
It forms a breathable barrier that blocks carbon dioxide and chloride ingress, the two main drivers of rebar corrosion in Indian concrete, while staying colour-stable under intense UV and monsoon exposure and letting trapped water vapour escape.
How is it applied?
Surface is grit-blasted and blowholes filled with Renderoc FC, the Dekguard Primer is flood-coated at 0.4 L/m2, then two coats of Dekguard S are brush, roller or airless-spray applied at 175 microns wet film each to reach a dry film thickness of at least 150 microns.
About Fosroc Dekguard Standard
Fosroc Dekguard Standard is the anti-carbonation protective coating system that pairs Fosroc Dekguard Primer with the Dekguard S top coat to safeguard the durability of reinforced concrete. In India’s environment, where airborne carbon dioxide, coastal salt, industrial sulphates and a harsh summer-then-monsoon cycle steadily attack cover concrete, this combination is specified to slow carbonation of the concrete cover and to keep chloride ions away from the embedded steel. The result is a longer service life for structures that would otherwise need expensive repair within a couple of decades.
The system works in two distinct layers, each doing a different job. The primer is a clear silane-siloxane dissolved in a penetrating organic carrier. Rather than sitting on the surface, it reacts within the pore structure of the concrete to create a chemically bound hydrophobic lining, so capillary water and the dissolved salts it carries are repelled before they can travel inward. On top of this, Dekguard S is applied as a pigmented, solvent-based aliphatic acrylic film. Its job is to act as a tough, gas-tight, UV-stable skin that resists carbon dioxide and chloride diffusion while still being open enough to let internal water vapour breathe out, so moisture is not trapped behind the coating.
For an Indian specifier, the most useful way to think about Dekguard Standard is as a finishing and protection layer in a complete Fosroc concrete-repair build-up. After cracked or spalled concrete is reinstated with the Renderoc range of repair mortars and any reinforcement primed against further corrosion, Dekguard Standard is what protects the whole repaired surface from the conditions that caused the damage in the first place. It is equally valid on sound new concrete as a preventive measure designed in at construction stage. Space Arc Engineering supplies and applies the system across Delhi NCR and Pan-India as an authorised Fosroc distributor and applicator, which means the primer, top coat, fairing coats and solvents are sourced as a matched set rather than mixed across brands.
The technical insight
The performance numbers explain why this is treated as a structural-durability product rather than a decorative paint. Independent testing on the Dekguard S film records carbon dioxide diffusion resistance equivalent to roughly 149 metres of air (Sd) under EN 1062-6, far above the BS EN 1504-2 minimum of 50 metres and well above the ~50 metre Klopfer threshold considered necessary to arrest carbonation; the Australian AS/NZS 4548.5 method reports an even higher equivalent air thickness of more than 200 metres for the same system. That CO2-tightness is what physically delays the carbonation front from reaching the steel. At the same time the coating stays a Class 1 (low) barrier to water vapour, measuring around 0.75 metres equivalent air thickness, so the system is gas-restrictive in the direction that matters and breathable in the direction that protects the substrate. Chloride performance is equally strong, with a reported reduction in chloride-ion penetration greater than 99 percent. The chemistry choice is deliberate: an aliphatic acrylic resin (rather than a cheaper aromatic one) is inherently UV-stable, which is why the film resists yellowing, chalking and gloss loss through years of Indian sun and rain, and also gives good resistance to surface dirt pick-up. Liquid water transmission stays below 0.1 kg/(m2.h^0.5) and pull-off bond strength to sound concrete exceeds 1 MPa, comfortably clearing the EN 1504-2 requirement.
Where it is used
- Anti-carbonation protection of exposed RCC facades, columns, beams and soffits on commercial and residential buildings
- Protective finish over Renderoc patch repairs on spalled or carbonated concrete
- Bridges, flyovers, ROBs and elevated metro viaducts exposed to traffic pollution and CO2
- Coastal and marine-adjacent structures defending rebar against chloride attack
- Water and effluent treatment plants, channels and retaining structures
- Industrial buildings exposed to acid gases and sulphate-laden atmospheres
- Heritage and institutional masonry needing a breathable, colour-stable protective coat
- Designed-in durability coating on new concrete for high-value or long-life assets
Key advantages
- Excellent barrier to carbon dioxide, chloride ions, sulphates, oxygen and water
- Breathable film lets internal water vapour escape, preventing blistering and trapped moisture
- UV-stable aliphatic acrylic resists yellowing, chalking and long-term weathering
- Conforms to BS EN 1504-2 surface protection principles 1.3, 2.2 and 8.2
- Single-pack primer and single-pack top coat, ready to use with no on-site mixing ratios
- Applies by brush, roller or airless spray to suit site access
- Available in a range of decorative colours, doubling as the finish coat
- Good resistance to dirt pick-up keeps facades cleaner for longer
- Integrates with the Fosroc Renderoc repair system as one matched build-up
Limitations & considerations
- Solvent-based and flammable (top coat flash point around 42 C); keep away from ignition sources and ventilate
- Not designed or suitable for trafficked or floor surfaces, where a Dekguard PU or Nitoflor system is required
- Should not be applied below 2 C substrate temperature or within 3 C of the dew point
- Should not be applied over elastomeric coatings, and overcoating existing paints needs trial-area compatibility checks
- Requires proper grit-blasting and blowhole filling (Renderoc FC) to form an unbroken film; poor prep undermines protection
- Batch-to-batch colour variation possible, so a single batch should be used for each elevation
- Not a crack-bridging coating; moving or live cracks need an elastomeric grade such as Dekguard Elastic
- Limited shelf life (about 12 to 18 months) and cure slows significantly in cold conditions
Selection & best practice
Treat Dekguard Standard as the last step of a complete durability system, not a standalone paint. Reinstate damaged concrete with the matching Renderoc mortars and let repairs cure, lightly grit-blast the whole surface to remove laitance, curing compounds and growth, then fill blowholes and pitting with Renderoc FC so the top coat can form a continuous film. Flood-apply Dekguard Primer at 0.4 L/m2 and let it dry for at least 12 hours at 20 C before overcoating. Apply two full coats of Dekguard S, each at not less than 175 microns wet film, respecting the 6-hour overcoat interval at 20 C, to reach the specified minimum 150 micron dry film thickness, then verify DFT with a wet-film comb during application. Use material from a single batch per elevation to avoid visible colour banding, mask glass and protect plants and sealants, and never apply below 2 C or within 3 C of dew point. On porous or doubtful substrates substitute Nitoprime DG for the primer and confirm with a trial panel.
Specifications
| Product type | Two-part system: silane-siloxane penetrating primer + single-component aliphatic acrylic top coat |
| Standard compliance | BS EN 1504-2 (principles 1.3, 2.2, 8.2); also tested to AS/NZS 4548.5 and BS 476 |
| Primary function | Anti-carbonation and anti-chloride protective & decorative coating |
| CO2 diffusion resistance (Sd) | ~149 m equivalent air (EN 1062-6); >200 m by AS/NZS 4548.5 |
| Water vapour permeability | Class 1, ~0.75 m equivalent air (EN ISO 7783-2) |
| Chloride-ion penetration reduction | >99% |
| Bond strength (pull-off) | >1.0 MPa (typically ~2.7 MPa) |
| Reaction to fire | Euroclass B (EN 13501-1); BS 476 Class 1 spread of flame, Class 0 Building Regulations |
| Minimum dry film thickness | 150 microns total (2 coats) |
| Wet film thickness per coat | 175 microns (Dekguard S) |
| Number of coats | Primer flood coat + 2 coats of Dekguard S top coat |
| Top coat coverage | ~6 m2 per litre per coat (~0.167-0.175 L/m2 per coat) |
| Primer coverage | ~2.5 m2 per litre (0.4 L/m2 application rate) |
| Volume solids (top coat) | ~43-44.5% |
| Overcoat time (Dekguard S @20 C) | 6 hours |
| Min. application temperature | 2 C substrate, and >3 C above dew point |
| Flash point | Dekguard S ~42 C; Dekguard Primer ~38 C |
| Pack size (India) | Dekguard S 20 L drum; Primer 20 L drum |
| Colour | White and a range of made-to-order BS 4800 colours |
| Shelf life | ~12-18 months in cool, dry, unopened storage |
Industry use cases
Infrastructure (bridges & metro)
Applied to bridge piers, girders and elevated viaducts where vehicle-exhaust CO2 and pollution accelerate carbonation, extending the maintenance-free life of the rebar cover.
Commercial & residential buildings
Used as a protective-decorative facade coat on RCC elevations, balconies and parapets, combining anti-carbonation performance with a UV-stable, dirt-resistant colour finish.
Coastal & marine structures
Specified on jet-ty-adjacent buildings, sea-front towers and port structures where its >99% chloride reduction defends embedded steel against salt-laden air.
Water & wastewater
Protects external faces of treatment tanks, channels and retaining walls from acid gases and sulphates while remaining breathable against trapped moisture.
Repair & rehabilitation
Finishes Renderoc-based concrete repairs on ageing structures, sealing the reinstated surface against the very conditions that caused the original distress.
Industrial plants
Coats structural concrete in chemical, fertiliser and process plants exposed to aggressive sulphate and acid-gas atmospheres.
Frequently asked questions
Is Fosroc Dekguard Standard the same as Dekguard S?
How does it actually stop rebar corrosion?
Why is breathability important if the coating is meant to seal the concrete?
What coverage and how many coats should I budget for?
Can it be used on floors, terraces or parking decks?
How is it different from Dekguard Elastic or Dekguard Ace?
How we position Fosroc Dekguard Standard
Within the Fosroc portfolio, Dekguard Standard is the workhorse anti-carbonation coating that finishes and protects a concrete-repair build-up. It pairs naturally with the Fosroc Renderoc repair mortars (such as Renderoc FC fairing coat for blowhole filling and Renderoc HB/GP for structural reinstatement), with Nitoprime DG as an alternative primer on porous substrates, and with reinforcement primers like Nitoprime Zincrich; for surfaces with live, moving cracks the elastomeric Dekguard Elastic is the right step up, while trafficked surfaces call for Dekguard PU or a Nitoflor floor system. Against the wider Indian market, credible alternatives a consultant may evaluate include Sika’s Sikagard anti-carbonation range (for example Sikagard-550 W Elastic and Sikagard-680 S), MBCC/Master Builders Solutions Masterprotect range, Pidilite Dr. Fixit Newcoat and anti-carbonation coatings, and STP Limited’s protective coating systems. These compete on similar BS EN 1504-2 performance, so selection in practice comes down to verified diffusion data, the matching repair-system ecosystem, applicator support and warranty. As an authorised Fosroc distributor and applicator in Delhi NCR and Pan-India, Space Arc Engineering recommends Dekguard Standard where a single, fully compatible Fosroc repair-and-protect specification is wanted, and will benchmark it honestly against the alternatives above when a project’s exposure, movement or budget points elsewhere.
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