Fosroc Dekguard Elite
A crack-bridging elastomeric acrylic coating that seals reinforced concrete against carbonation, chloride ingress and weathering — while staying breathable and colour-stable for years.
What is it?
A high-build, water-based elastomeric acrylic anti-carbonation coating from the Fosroc Dekguard range, applied as a primer-plus-topcoat system over concrete and masonry.
Where is it used?
Atmospherically exposed reinforced concrete — building facades, bridges, storage tanks, precast panels and coastal structures — above splash zones.
Why use it?
It stops CO2 and chloride ingress that drive rebar corrosion, bridges fine surface cracks, and lets trapped vapour escape, all in one decorative finish.
How is it applied?
Prepared substrate is primed with the Dekguard silane-siloxane primer, then the pigmented elastomeric topcoat is brushed, rolled or sprayed in two coats to at least 200 microns dry film thickness.
About Fosroc Dekguard Elite
Dekguard Elite sits in Fosroc’s Dekguard family of protective and decorative coatings, the elastomeric grade built for concrete that is at risk of carbonation and, sooner or later, of hairline cracking. Reinforced concrete is alkaline when new, and that alkalinity is what keeps the embedded steel passive and rust-free. Over years of exposure, atmospheric carbon dioxide reacts with the concrete and drops its pH — carbonation — until the steel loses that protection and begins to corrode, spall and crack the cover. In coastal and marine belts, wind-driven chlorides accelerate the same process. Dekguard Elite is applied to the outer face of the structure to shut this cycle down before it starts, or to arrest it on structures already showing early distress.
Unlike a rigid paint that cracks when the substrate moves, this coating is a flexible acrylic film that stretches over minor cracks and keeps its seal, even after prolonged UV weathering. It is supplied as a complete system: a penetrating silane-siloxane primer that consolidates and water-repels the surface, followed by a pigmented elastomeric topcoat available in a wide colour range. Space Arc Engineering supplies and applies the full Dekguard system across Delhi NCR and Pan-India, so specifiers get the primer, topcoat and site guidance from one authorised source rather than sourcing parts separately.
The technical insight
The protection is a diffusion story, not just a cosmetic one. Carbonation depends on how easily CO2 can migrate through the cover concrete to the steel; the Dekguard elastomeric film raises that resistance dramatically, equivalent to roughly 240 metres of still air (Taywood method) or more than 500 mm of additional 30N concrete cover. That single coating therefore does the job of a huge notional thickness of concrete in slowing the carbonation front. At the same time its water-vapour diffusion resistance is deliberately kept low — an SD of about 1.0 m at 200 microns — so moisture already inside the slab can breathe out instead of blistering the film. The elastomer itself is what handles movement: at 200 microns dry film thickness it spans static cracks up to 2 mm at 23 degrees C and absorbs cyclic movement of about 1 mm, so the barrier stays continuous even as the structure works. Together, high gas resistance plus real crack accommodation is why an elastomeric grade outlasts a conventional anti-carbonation paint on a moving facade.
Where it is used
- Anti-carbonation protection of atmospherically exposed reinforced concrete building facades
- Crack-bridging decorative coating over concrete showing early hairline cracking
- External surfaces of concrete storage tanks and water-retaining structures (above splash zones)
- Bridge decks soffits, piers and RCC infrastructure in aggressive environments
- Precast concrete panels and architectural cladding requiring a uniform colour finish
- Coastal and marine structures exposed to chloride-laden air
- Refurbishment of ageing facades combining protection with an aesthetic upgrade
- Final protective layer over Renderoc concrete-repair patches to unify and shield the surface
Key advantages
- Elastomeric film bridges substrate cracks up to 2 mm and absorbs ~1 mm cyclic movement at 200 microns DFT
- Very high carbonation resistance — equivalent to ~240 m of air / >500 mm of concrete cover to CO2
- Breathable: low vapour resistance (SD ~1.0 m) lets the structure dry out instead of blistering
- Strong barrier to chloride ions, water and sulphates, reducing water absorption by over 80%
- Water-based and low-VOC (~4.75 g/l), easier and safer to apply on occupied and enclosed sites
- Retains flexibility and colour after long-term UV exposure and heavy rain
- Wide made-to-order colour range for a decorative as well as protective finish
- Applies by brush, roller or airless spray, suiting both small refurbishments and large facades
Limitations & considerations
- A protective barrier coating, not a structural repair — actively spalling or delaminated concrete must be reinstated with a Renderoc mortar first
- Intended for surfaces above splash zones; it is not a substitute for a below-grade tanking membrane or for immersion service
- Full crack-bridging performance depends on achieving the specified two-coat 200-micron dry film — thin or single-coat application under-performs
- Requires the matching Dekguard primer and a sound, clean, laitance-free substrate for adhesion; it will not stick reliably to dusty or friable surfaces
- Being elastomeric and matt-to-low-sheen, it is not a high-gloss or heavy-duty trafficable floor coating
- Application and curing are temperature and moisture sensitive; work should pause in rain or on very cold, damp substrates
Selection & best practice
Start with the substrate, because adhesion and film build decide everything. Remove laitance, dirt, oil and any loose or carbonated concrete, and reinstate spalled or cracked areas with the appropriate Fosroc Renderoc mortar before coating. Where corroded reinforcement is exposed during repair, prime the steel with Nitoprime Zincrich first. Allow repairs and new concrete to cure, then apply the Dekguard silane-siloxane primer to the whole area to consolidate and water-repel the surface. Follow with the elastomeric topcoat in two full coats — do not try to reach the target film in one pass — building to a total dry film thickness of not less than 200 microns; this is the thickness at which the quoted crack-spanning and CO2 figures are achieved. Keep a wet edge, respect the overcoating interval between coats, and avoid application in rain or on damp, dew-covered surfaces. On large facades, spray for output but back-roll to guarantee an even, pinhole-free film. Confirm final film build with a wet-film gauge as you go rather than after the coating has dried.
Specifications
| Product type | Elastomeric, water-based acrylic anti-carbonation protective coating |
| System | Silane-siloxane primer + pigmented elastomeric topcoat |
| Total dry film thickness | Not less than 200 microns, applied in 2 coats |
| CO2 diffusion resistance | ~240 m equivalent air thickness; >500 mm equivalent 30N concrete cover (Taywood) |
| Water vapour resistance (breathability) | SD ~1.0 m at 200 microns DFT (Klopfer method) |
| Static crack spanning | Up to 2 mm at 200 microns DFT, 23 degrees C (modified ASTM C836-76) |
| Volume solids | 50% (solids by weight 64%) |
| Tensile strength / adhesion | 5.0 N/mm2 (ASTM D412); adhesion to concrete 1.0 N/mm2 (BS 1881) |
| Finish and colour | Matt to low-sheen; wide made-to-order colour range |
Industry use cases
Commercial and residential facades
Protects exposed RCC frames and plaster on high-rise and mid-rise buildings from carbonation while giving the elevation a fresh, uniform colour that resists dirt pick-up.
Bridges and highway infrastructure
Coats piers, girders and soffits to slow chloride and CO2 ingress, extending the maintenance cycle of ageing RCC structures in polluted and coastal corridors.
Coastal and marine construction
Shields concrete in salt-laden air along seafronts, ports and jetties (above splash zones) where chloride-driven rebar corrosion is the main durability threat.
Water and industrial tanks
Provides an external anti-carbonation and anti-chloride barrier on storage tanks and process structures that also flexes over the fine cracking such vessels develop.
Repair and rehabilitation projects
Serves as the final protective overcoat on Renderoc-repaired concrete, unifying patched areas and preventing the repaired structure from re-carbonating.
Frequently asked questions
Is Dekguard Elite the same as a normal exterior emulsion paint?
How does the coating stop rebar corrosion if it only sits on the surface?
Can it be applied over concrete that already has cracks?
Does the coating trap moisture inside the concrete?
How many coats are needed and what thickness should we specify?
Does Space Arc supply the primer and provide application support?
How we position Fosroc Dekguard Elite
Dekguard Elite is the elastomeric, crack-bridging grade of Fosroc’s Dekguard anti-carbonation range. If the concrete is sound and unlikely to crack, the non-elastomeric Dekguard S is a more economical anti-carbonation choice; where wider live cracking (up to 6 mm) is expected, step up to Dekguard Elastic, the highest-movement grade in the family. On rehabilitation jobs, Dekguard is the finishing layer over a repair sequence — reinstate the concrete with a Fosroc Renderoc mortar and prime exposed steel with Nitoprime Zincrich first, then coat. For below-grade or immersed surfaces this is the wrong tool; specify a tanking membrane or a Fosroc waterproofing system instead. Space Arc also carries Dr. Fixit, Sika and MC-Bauchemie protective-coating equivalents when a project standard calls for a specific brand.
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