Fosroc Dekguard FCL
A ready-to-use, water-based acrylic emulsion protective coating that guards reinforced concrete against carbonation, chloride ingress and weathering, with a durable matt decorative finish.
What is it?
A single-component, water-based acrylic emulsion protective and decorative coating from Fosroc that forms a continuous barrier against carbon dioxide, water and chloride ions on concrete and masonry.
Where is it used?
External facades, RCC frames, bridges and flyovers, parking structures, water-retaining and coastal/marine structures, and repaired concrete that needs long-term protection from carbonation and weathering.
Why use it?
It slows carbonation-driven reinforcement corrosion while staying breathable, so trapped moisture can escape, and it delivers a decorative matt finish in a wide colour range from a low-VOC water-based product.
How is it applied?
Brush, roller or airless spray over clean, sound, prepared concrete in two coats; ready for immediate site use with no on-site mixing of base and hardener.
About Fosroc Dekguard FCL
Fosroc Dekguard FCL is a high-performance anti-carbonation protective coating engineered to extend the service life of reinforced concrete structures. It is a single-component, water-based acrylic emulsion that arrives ready for immediate site use, which removes the mixing-ratio errors and pot-life pressure that come with two-pack systems. Once applied and cured, it forms a continuous, flexible film that acts as a barrier to the three agents most responsible for premature concrete deterioration in the Indian climate: atmospheric carbon dioxide, water, and chloride ions.
The core problem Dekguard FCL addresses is carbonation. Atmospheric CO2 reacts with the alkaline calcium hydroxide in concrete, lowering its pH and stripping away the passive oxide layer that normally protects embedded steel reinforcement. Once that protection is lost, the steel corrodes, expands, and cracks or spalls the cover concrete. By presenting a high-resistance barrier to CO2 diffusion at the surface, Dekguard FCL keeps the carbonation front from reaching the rebar, buying years of additional life for the structure. Crucially, the coating is also vapour-permeable: it lets water vapour escape from within the concrete while blocking liquid water and dissolved chlorides from getting in, so it does not trap moisture behind the film.
For Indian projects, the water-based acrylic chemistry is a practical advantage. It is low-odour and low-VOC compared with solvent-based coatings, which makes it more comfortable to apply on occupied buildings, in enclosed areas, and on facades in dense urban settings such as Delhi NCR. The matt finish and wide decorative colour range mean a single product can serve both the protective and the aesthetic brief, letting architects specify a durable facade colour that doubles as the durability system. As an authorised Fosroc distributor and applicator, Space Arc Engineering supplies Dekguard FCL with the matching Fosroc surface-preparation and concrete-repair products needed to make the coating perform as intended.
The technical insight
Dekguard FCL belongs to Fosroc’s Dekguard family of surface-protection coatings, which are formulated and tested as anti-carbonation systems under BS EN 1504-2 (surface protection of concrete, performance principles 1.3, 2.2 and 8.2). The defining technical property of any coating in this class is its resistance to carbon dioxide diffusion, expressed as an equivalent air-layer thickness, Sd (in metres). EN 1504-2 requires an anti-carbonation coating to demonstrate an Sd value greater than 50 m when tested to EN 1062-6; the Dekguard acrylic system is documented to far exceed this, with published Sd figures around 140 to 149 metres of air. The higher the Sd, the slower CO2 can penetrate, which directly governs how long the coating defers carbonation reaching the steel. At the same time these coatings keep liquid-water transmission low (EN 1062-3, less than 0.1 kg/m2.h^0.5) while remaining vapour-open, and Aston University diffusion-cell testing on the family shows chloride-ion reduction in excess of 99 percent. The performance therefore depends as much on continuity of the film as on the chemistry: an unbroken, correctly built-up film at the specified dry film thickness is what delivers the rated CO2 and chloride resistance, which is why surface preparation, primer where required, and achieving full coverage over two coats are non-negotiable. Always confirm the project-specific values against the current Fosroc India TDS for Dekguard FCL before specification.
Where it is used
- External anti-carbonation and weather-protective coating for concrete and masonry facades
- Protection of RCC bridges, flyovers, viaducts and elevated metro structures from carbonation and chloride attack
- Decorative and protective coating for multi-storey car parks and parking decks (vertical and soffit surfaces)
- Coastal, marine and water-retaining structures exposed to chlorides and high humidity
- Industrial buildings, warehouses and chimneys subject to aggressive atmospheres and acid gases
- Overcoating of repaired concrete and Renderoc-type repair mortars to unify and protect the surface
- Aesthetic recoating of ageing concrete facades where both colour and durability are required
Key advantages
- Single-component and ready to use, so there is no on-site mixing ratio to get wrong and no pot-life waste
- High resistance to carbon dioxide diffusion, slowing carbonation and protecting embedded reinforcement
- Allows water vapour to escape while blocking liquid water and chloride ions, so it does not trap moisture in the concrete
- Water-based, low-odour and low-VOC, suitable for occupied buildings and enclosed or urban environments
- Durable under long-term weathering and UV with good resistance to dirt pick-up
- Decorative matt finish available in a wide colour range, combining protection with appearance
- Applies by brush, roller or airless spray over a range of concrete and masonry substrates
Limitations & considerations
- Not a structural or crack-bridging repair product; active or moving cracks must be repaired first with appropriate Fosroc systems
- Performance depends on thorough surface preparation; will not bond well over dirty, friable, oily or laitance-covered concrete
- As a water-based coating it should not be applied in rain, at low temperatures or in conditions that prevent proper film formation and drying
- A continuous, correctly built-up two-coat film at the specified thickness is required; thin or missed areas compromise the rated CO2 and chloride resistance
- Generally not recommended for permanent water immersion or as a tanking/waterproofing membrane; it is a vapour-permeable protective coating
- Not formulated for chemical-tank linings or heavy chemical immersion duty, where epoxy or polyurethane systems are more appropriate
- Colour-critical and exact technical values should be confirmed against the current Fosroc India TDS, as published figures vary by region and revision
Selection & best practice
Start with sound substrate: the concrete must be clean, dry, fully cured and free of laitance, dust, oil, grease, curing compounds and loose or friable material. Make good blowholes, honeycombing and surface defects with a Fosroc fairing or repair product (such as a Renderoc fairing coat or repair mortar) and allow repairs to cure before coating. Where the substrate or the system requires it, apply the recommended Fosroc primer first. Stir Dekguard FCL thoroughly before use and apply in two continuous coats by brush, roller or airless spray, working each coat to a uniform, unbroken film and respecting the stated coverage so the specified dry film thickness is achieved; allow the first coat to dry fully before recoating. Do not apply in rain, on damp surfaces, or below the minimum application temperature, and protect freshly coated surfaces from rain until properly dry. Use material from the same batch on continuous elevations to avoid colour variation, and verify coverage on a trial area for the actual surface texture. Always work to the current Fosroc India technical data sheet and method statement for Dekguard FCL.
Specifications
| Product type | Single-component, water-based acrylic emulsion protective and decorative coating (ready to use) |
| Primary function | Anti-carbonation barrier coating; protects against CO2, water and chloride ions |
| Finish | Matt, decorative |
| Colour | Wide decorative colour range |
| Substrates | Concrete and masonry (incl. repaired concrete / repair mortars) |
| Number of coats | Typically 2 coats (confirm per Fosroc India TDS) |
| Application methods | Brush, roller or airless spray |
| Performance standard (class) | Dekguard anti-carbonation system tested to BS EN 1504-2 (principles 1.3, 2.2, 8.2) |
| CO2 diffusion resistance (class) | EN 1062-6: Sd > 50 m required; Dekguard acrylic system documented ~140-149 m of air |
| Liquid water transmission (class) | EN 1062-3: < 0.1 kg/m2.h^0.5 (low, while remaining vapour-permeable) |
| Chloride-ion reduction (class) | >99% (Aston University diffusion-cell test on Dekguard system) |
| Coverage (class reference) | Dekguard S approx. 6 m2/litre per coat; confirm FCL value on its TDS |
| Base | Water-based / aqueous (low-odour, low-VOC) |
| Supply | Ready-to-use packs; confirm pack sizes with Space Arc Engineering / Fosroc India |
Industry use cases
Infrastructure & bridges
Anti-carbonation protection of RCC bridge piers, decks soffits, flyovers and elevated metro corridors exposed to traffic pollution and CO2, extending service life before chloride and carbonation reach the reinforcement.
Commercial & residential facades
Durable decorative coating for high-rise and institutional concrete facades in Delhi NCR, combining a matt architectural colour with breathable, weather-resistant protection.
Car parks & podiums
Protection of vertical and soffit concrete in multi-storey car parks, where de-icing salts, vehicle exhaust and water accelerate chloride-induced corrosion.
Coastal & marine
Surface protection of structures in coastal and high-humidity zones where airborne chlorides drive rapid rebar corrosion, used alongside Fosroc repair systems.
Industrial plants
Coating of warehouses, process buildings, chimneys and structures subject to acid gases, sulphates and aggressive atmospheres.
Repair & refurbishment
Overcoating of patch-repaired concrete and fairing coats to unify appearance and re-establish a continuous protective barrier over the whole element.
Frequently asked questions
Is Fosroc Dekguard FCL a genuine Fosroc product?
What does Dekguard FCL actually protect concrete from?
How is Dekguard FCL different from Dekguard S or Dekguard Standard?
How many coats are needed and how is it applied?
Can Dekguard FCL be used as a waterproofing membrane?
How does it compare with alternatives from Sika, MYK Arment, Dr. Fixit or STP?
How we position Fosroc Dekguard FCL
Within Fosroc’s own range, Dekguard FCL is the water-based, ready-to-use entry point to anti-carbonation protection, sitting alongside the solvent-based Dekguard S (semi-gloss aliphatic acrylic), the primer-plus-topcoat Dekguard Standard system, the crack-accommodating Dekguard Elastic / E2000 for facades that move, and clear options like Dekguard CP/Incoloro where the natural concrete look must be retained. It is best specified together with Fosroc’s Renderoc concrete-repair mortars and fairing coats and, where needed, the matching Dekguard primer, so the structure is repaired and then protected as one EN 1504-compliant system. Against the wider Indian market it competes with Sika’s Sikagard anti-carbonation coatings (e.g. Sikagard-550W Elastic, 680S), MYK Arment (formerly MBS) acrylic protective coatings, Dr. Fixit’s acrylic facade and protective coatings, and STP/Pidilite facade systems. Honestly assessed, no single product dominates on every metric; the right specification is driven by the verified CO2-diffusion (Sd) value, breathability, crack-bridging need, colour and the strength of the accompanying repair ecosystem. Dekguard FCL’s clearest advantage is being one component of Fosroc’s tightly integrated, well-documented repair-and-protect family, supplied and applied in Delhi NCR and Pan-India by Space Arc Engineering as an authorised Fosroc distributor and applicator.
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