About Fosroc Dekguard Elastic

Fosroc Dekguard Elastic is a high-performance, crack-accommodating elastomeric coating engineered to protect atmospherically exposed reinforced concrete from the two corrosion drivers that matter most in the Indian environment: atmospheric carbonation and chloride attack. It is part of Fosroc’s wider Dekguard family of protective coatings and integrates with the Renderoc concrete repair system, making it the natural finishing layer once spalled cover concrete has been reinstated.

Chemically, it is a water-based coating built on a special acrylic polymer. What sets it apart from a conventional anti-carbonation paint such as Dekguard S is its elastomeric nature — the cured film behaves like a flexible membrane rather than a brittle skin. The complete system is two parts: Nitoprime DG, an acrylic film-forming penetrating silane-siloxane primer that stabilises and seals the substrate, followed by the pigmented Dekguard Elastic topcoat applied in two coats. Both components arrive ready for immediate site use, which suits fast-moving Indian site conditions where minimal mixing reduces error.

The product carries CE marking and conforms to BS EN 1504-2, the European standard for surface protection systems for concrete, addressing Principles 1.3 (protection against ingress), 2.2 (moisture control) and 8.2 (increasing resistivity). For specifiers writing tender clauses in India, where IS codes do not yet cover anti-carbonation coatings in detail, BS EN 1504-2 is the most widely accepted reference and Dekguard Elastic’s documented test results make it straightforward to specify and audit. It is suited equally to new construction and to the rehabilitation of ageing structures, including those in aggressive coastal and industrial atmospheres along India’s long coastline.”,

“technicalInsight”

The technical insight

The defining property is crack-bridging. Tested to UNE EN 1062-7, Dekguard Elastic achieves Class IV (>1250 microns), with a measured value of 1595 microns — meaning the film stays continuous across cracks that would split a rigid coating. The published advantage of accommodating substrate cracking up to 6 mm and cyclic movement up to 1 mm comes from this elasticity, which is retained even at sub-zero temperatures, and from an elongation at break exceeding 400% (ASTM D412). The trade-off engineers must understand: crack-bridging is a function of film thickness, so the 400-micron minimum DFT is not optional — it is what delivers the rated performance. Equally important is its dual barrier behaviour. Carbon dioxide permeability is measured at Sd 106 m (EN 1062-6, requirement >50 m), and the system provides CO2 diffusion resistance equivalent to more than 125 mm of 30 N/mm2 concrete cover by the Taywood method — effectively adding a century-plus of notional cover against carbonation. At the same time it remains breathable: water-vapour permeability is Class 1 with Sd of 0.76 m (EN ISO 7783-2), so trapped moisture can escape rather than blistering the film, while liquid water permeability is just 0.02 kg/m2.h0.5 (EN 1062-3). When used with its primer, chloride ion penetration is reduced by more than 99% (Aston University diffusion cell), and pull-off bond strength is 1.13 MPa (EN 1542). This combination — high CO2 and chloride resistance, high vapour breathability, and genuine elasticity — is difficult to achieve simultaneously and is the core technical reason to choose Elastic over a standard acrylic.

Where it is used

• Anti-carbonation protection of bridge piers, decks soffits, crash barriers and flyover structures exposed to vehicular CO2
• Coastal and marine RCC structures — jetties, sea-front buildings, parapets — needing chloride-ingress resistance
• Finishing coat over Renderoc patch-repaired columns, beams and slabs in concrete rehabilitation projects
• Building facades, parapets, chajjas and fins where hairline cracking is expected and a decorative coloured finish is required
• Water-retaining and water-treatment structures (external faces) requiring a breathable protective barrier
• Industrial structures exposed to acid gases and aggressive atmospheres
• Multi-storey car parks and elevated corridors subject to thermal and live-load movement

Key advantages

• Bridges substrate cracks up to 6 mm and accommodates ~1 mm cyclic movement, keeping the barrier intact over working concrete
• True elastomeric film with >400% elongation at break (ASTM D412), retaining flexibility at sub-zero temperatures
• Excellent simultaneous barrier to carbon dioxide, chloride ions, oxygen and water — equivalent to >125 mm of 30 N/mm2 concrete cover against CO2
• Breathable: Class 1 water-vapour permeability (Sd 0.76 m) lets trapped moisture escape, reducing blistering risk
• Conforms to BS EN 1504-2 (Principles 1.3, 2.2, 8.2) — easy to specify and audit in Indian tenders
• Water-based and low-odour; tools clean with water, suitable for occupied-building and confined exteriors
• Reduces chloride ion penetration by >99% when used with Nitoprime DG primer
• Wide range of decorative colours and good long-term UV / weathering resistance with low dirt pick-up
• Integrates with Fosroc Renderoc repair system as a single-source protective specification

Limitations & considerations

• Requires a minimum total DFT of 400 microns — under-application directly compromises the rated crack-bridging and CO2 resistance
• Two-component system: needs the Nitoprime DG primer on bare concrete, adding a step and a 12-hour primer drying wait at 20 C
• Substrate temperature must be at or above 5 C (2 C for the primer); cure times lengthen and quality drops in cold conditions
• Long overcoating intervals (primer 12 h, topcoat 16 h at 20 C) extend programme time versus single-coat paints
• Not formulated for permanent water immersion or for trafficked / pedestrian-wear surfaces; it is an atmospheric-exposure coating
• Performance and fire rating can be impaired when applied over existing coatings — trial panels and special priming are required
• Higher material cost per square metre than rigid anti-carbonation paints; justified only where movement / cracking is genuinely expected
• Surface preparation is demanding — grit-blasting, blowhole filling with Renderoc FC and biocide treatment of algae are often needed

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Dekguard Elastic

Within the Fosroc range, Dekguard Elastic sits at the high-performance, movement-tolerant end of the protective-coatings family. Specify it over the rigid Dekguard S or Dekguard ET when the concrete is expected to crack or move and the anti-carbonation barrier must survive that movement; choose Dekguard S where the substrate is sound and a lower-cost, non-flexible coating suffices. It is designed to follow Fosroc’s Renderoc repair mortars and the Nitoprime DG primer as a single-source repair-and-protect specification, which simplifies accountability on rehabilitation contracts. Against competitors in India, the closest crack-bridging anti-carbonation alternatives are Sika’s Sikagard-550 W Elastic (a well-regarded elastomeric coating with comparable BS EN 1504-2 credentials), MBS / MC-Bauchemie’s MC-Color Flex elastic coating, STP Limited’s flexible acrylic anti-carbonation coatings, and within the waterproofing-led brands Dr. Fixit’s elastomeric exterior coatings (though these are positioned more as decorative-waterproof than dedicated anti-carbonation systems). Dekguard Elastic’s strengths in this field are its documented Class IV crack-bridging, strong simultaneous CO2 and chloride resistance, and tight integration with the Fosroc repair ecosystem; its trade-offs are a higher per-square-metre cost and a two-coat-plus-primer programme that only pays off where genuine movement or cracking is present. For purely stable substrates, or where budget dominates, a rigid anti-carbonation paint from Fosroc or a competitor will often be the more economical specification.

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