Dekguard S: High Performance Aliphatic Acrylic Protective Coating

Overview

Dekguard S is a high-performance, pigmented aliphatic acrylic protective and decorative coating designed for concrete and masonry structures. Manufactured and supplied by Fosroc, this solvent-based system provides outstanding resistance to aggressive environmental elements, making it an excellent choice for protecting atmospherically exposed, non-trafficked reinforced concrete structures from multiple forms of attack.

Key Features and Advantages

Dekguard S offers several distinctive advantages that make it particularly suitable for demanding applications:

• Excellent barrier properties: Provides an excellent barrier to carbon dioxide, chloride ions, and water penetration
• Water vapour transmission: Allows water vapour to escape from the structure while blocking liquid water
• UV resistance: Highly UV-resistant aliphatic acrylic formulation gives exceptional resistance to the effects of long-term weathering
• Versatile application: Suitable for use on all types of concrete structures, especially those in aggressive marine and coastal environments
• Compatibility: Compatible with the Renderoc system of concrete reinstatement products
• New and existing structures: Equally suitable for both new and existing structures

Intended Uses

Dekguard S is specifically designed to protect atmospherically exposed reinforced concrete structures from attack by:

• Acid gases
• Chloride ions
• Water damage
• UV light degradation

The product is especially suitable for structures in aggressive marine and coastal environments where chloride ion exposure is a significant concern. Dekguard S should be considered as an alternative coating product for areas subjected to exposure to occasional ponded water, whereas Dekguard Elastic should not be used in these applications.

Product Composition and Description

Dekguard S is an aliphatic acrylate, solvent-based protective coating that provides outstanding resistance to aggressive elements and rain. The system comprises two components:

1. Dekguard Primer: A silane-siloxane based primer capable of producing a chemically-bound hydrophobic barrier that inhibits the passage of water and water-borne contaminants
2. Dekguard S topcoat: The main protective coating applied over the primed surface

The product is available in two shades of grey: Concrete Grey and Bridge Grey.

Design Criteria and Application Specifications

Dry Film Thickness (DFT)

The coating system should be applied in two coats to achieve a total dry film thickness of not less than 150 microns. This specification is critical to achieve the correct protective properties of the system.

Application Rates

To achieve the correct protective properties, Dekguard S must be applied at the recommended coverage rate:

• Coverage rate: 6 m²/litre per coat (or 0.167 litres/m² per coat)
• Total coverage: 3.0 m²/litre (total in 2 coats)

Wet Film Thickness (WFT)

Each coat of Dekguard S must achieve a theoretical wet film thickness not less than 175 microns to ensure proper coating performance.

Overcoating Times

Overcoating times vary with ambient temperature:

Temperature	Overcoating Time
2°C	12 hours
20°C	6 hours
30°C	5 hours

Performance Properties

Dekguard S demonstrates exceptional protective characteristics:

Diffusion Resistance

• Carbon dioxide diffusion resistance (R): 378 metres equivalent air thickness
• Equivalent concrete cover (Sc): 940 mm
• CO₂ diffusion coefficient: 7.1 × 10⁻⁸ cm²/sec

Water Vapour Transmission

• Vapour transmission rate: 21.9 g/m²/24hr
• Equivalent air thickness (Sd): 2 metres
• Vapour diffusion coefficient: 2.7 × 10⁻⁵ cm²/sec

Chloride Ion Protection

• Reduction in chloride ion penetration: 99% (Aston University Diffusion Cell method)
• Chloride ion diffusion coefficient: 1.0 × 10⁻¹⁴ m²/sec @ 147 days

Additional Properties

• Volume solids: 37%
• VOC content: 781 g/litre

Surface Preparation Requirements

Proper surface preparation is essential for optimal performance. All surfaces should be:

• Dry and free from contamination
• Free from oil, grease, loose particles, decayed matter, moss, and algal growth
• Free from laitance and all traces of mould release oils and curing compounds
• Best achieved by lightly grit-blasting the surface

Where moss, algae, or similar growths have occurred, treatment with a proprietary biocide should be carried out after the grit-blasting process.

Compatibility Trials

Where application over existing sound coatings or paints is required, trials should be conducted to ensure compatibility and retention of the bond between the underlying coating and the substrate. Bond retention must be assessed through compatibility trials before full application. When applied over existing coatings or paints, the performance characteristics of Dekguard S may be impaired.

Surface Defects

Surfaces containing blow-holes or similar areas of pitting should first be filled using:

• Renderoc FC, or
• Renderoc ST 06 (a cementitious fairing coat)

These fairing coats should be allowed to cure for approximately 48 hours depending on ambient conditions before the application of Dekguard S.

Primer Application

Dekguard S must be applied following the application of a primer, such as:

• Dekguard Primer, or
• Nitocote SN511

Dekguard Primer Specifications

• Number of coats: Flood coat
• Application rate: 2.5 m²/litre (0.4 litres/m²)
• Overcoating time: 2 hours @ 20°C

Alternative Primer: Nitoprime DG

Very porous surfaces may require the application of Nitoprime DG as an alternative primer. Nitoprime DG should be applied at the same coverage rate as Dekguard Primer in continuous, multiple coats as necessary.

The primer should be allowed to dry for a minimum of two hours at 20°C before application of Dekguard S. Under no circumstances should the primer be overcoated until the surface is properly dry.

Topcoat Application Method

All primed substrates should be treated with two coats of Dekguard S. The material should be stirred thoroughly before use.

The material can be applied using:

• Suitable brushes
• Rollers
• Spray equipment

Each coat should achieve a uniform coating with a wet film thickness not less than 175 microns. This coat should be allowed to dry before continuing to the second coat.

Application Conditions and Limitations

Substrate Temperature

Application should not commence if the temperature of the substrate is below 2°C.

Protected Areas

During application, the following areas should be protected or masked:

• Any areas of glass (masked)
• Plants
• Grass
• Joint sealants
• Asphalt surfaces
• Bitumen-painted areas

Non-Trafficable Use

Dekguard S is not designed nor suitable for use on trafficable surfaces. It is specifically formulated for protective coating applications on non-trafficked concrete and masonry structures.

Ponded Water Applications

Dekguard S should be considered for areas where occasional ponded water is anticipated, providing an alternative to products not designed for such exposure conditions.

Cleaning and Removal

Dekguard S should be removed from tools and equipment using Fosroc Solvent 10. This solvent is specifically recommended for cleaning all application equipment and tools used with the product.

Supply and Product Variants

Dekguard S is available in the following supply configurations:

Product	Product Code
Dekguard S Concrete Grey 15 litres	FC860623-15L
Dekguard S Bridge Grey 15 litres	FC860624-15L
Dekguard Primer 20 litre	FC861520-20L
Nitoprime DG 20 litre	FC862600-20L
Nitocote SN511 20 litre drum	FC855155-20L
Nitocote SN511 200 litre drum	FC855155-200L
Fosroc Solvent 10 4 litre	FC600800-4L
Fosroc Solvent 10 20 litre	FC600800-20L

Storage Requirements

Store Dekguard S in cool, dry conditions, away from sources of heat and naked flames.

Safety Documentation

A Safety Data Sheet (SDS) is available from the Fosroc website and must be read carefully prior to application, as application or performance data may change from time to time.

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References

• [1] Fosroc_Dekguard_S_TDS.pdf
• [2] Fosroc_Dekguard_Primer_TDS.pdf
• [3] Fosroc_Nitoprime_DG_TDS.pdf
• [4] Fosroc_Nitocote_SN511_TDS.pdf