Frequently Asked Questions

What is the difference between Dekguard S and Dekguard W and when should each be specified for concrete facade protection?

Dekguard S and Dekguard W are both elastomeric anti-carbonation protective coatings from Fosroc for concrete facades — the primary difference is in the solvent or carrier system. Dekguard S is solvent-based, using an organic solvent carrier for the acrylic elastomer, while Dekguard W is water-based (waterborne acrylic elastomer in an aqueous dispersion). From a performance standpoint, both products provide effective anti-carbonation protection, UV and weather resistance, elastomeric crack bridging, and vapour permeability. The choice between the two is typically made on the basis of site conditions and environmental preferences. Dekguard S is generally preferred for dense, low-porosity substrates (high-quality formed concrete) where the solvent carrier aids penetration of the primer into the less-porous surface; for cold weather application where waterborne coatings may have minimum temperature limitations that restrict use; and for applications where the faster dry time of a solvent-based system is needed. Dekguard W is preferred where solvent emissions are restricted (indoor car parks, enclosed spaces with ventilation limitations, or where solvent-free specification is required for environmental compliance).

How many coats of Dekguard S are needed and what is the minimum dry film thickness for effective anti-carbonation protection?

For effective anti-carbonation protection of concrete facades, Dekguard S is applied in two coats over the appropriate Nitoprime primer coat, building up a minimum total dry film thickness (DFT) of 200 to 250 microns. The primer coat (Nitoprime 25 or 30 as specified) is applied first to the cleaned and prepared concrete surface to improve adhesion of the elastomeric topcoat. The first coat of Dekguard S is then applied at a coverage of approximately 5 to 6 square metres per litre and allowed to dry before the second coat is applied (minimum 6 to 8 hours at 25 degrees Celsius). The second coat is applied in a cross-direction to the first to ensure uniform coverage and build the specified film thickness. At 200 to 250 microns DFT, the Dekguard S system provides the CO2 diffusion resistance (equivalent air layer thickness exceeding 100 metres as per EN 1062-6) required for effective anti-carbonation protection. For bridges and infrastructure in high-pollution environments, increasing to three coats to build a DFT of 300 to 350 microns is sometimes specified for longer intervals between recoating.

How long does a Dekguard S protective coating last on a concrete facade and when does it need to be maintained or reapplied?

The expected service life of a Dekguard S coating system on a well-prepared concrete facade under Indian climatic conditions is typically 10 to 15 years before inspection and maintenance recoating is needed. The actual service life depends on several factors: the quality of surface preparation and primer application before the Dekguard S coats (inadequate preparation results in shorter adhesion life); the UV and thermal exposure of the facade (south-facing walls and horizontal surfaces receive more UV than north-facing vertical surfaces); the atmospheric pollution loading (facades facing busy roads in Delhi NCR may experience more rapid weathering than facades in sheltered positions); and the specification of DFT (thicker applications last longer). Maintenance inspection should be carried out every 5 to 7 years — checking for areas of localised delamination, cracking through the film, chalking, or colour fade. Where localised defects are found, spot repair followed by a full maintenance overcoat of Dekguard S can restore the protective system to near-original performance without complete removal of the existing coating, provided the underlying coating is well-adhered.