About Fosroc Brushbond Roofguard

Fosroc Brushbond Roofguard is a high-build, fibre-reinforced acrylic elastomeric waterproofing render developed specifically for the exposed roofs and terraces that take the brunt of the Indian monsoon and summer sun. Unlike thin acrylic paints that merely decorate, Roofguard is a single-component, polymer-modified liquid that cures into a tough, seamless, elastic film capable of bridging hairline shrinkage and thermal cracks while staying firmly bonded to the substrate. It is supplied ready to use and is applied by brush or roller, which makes it a practical choice for occupied buildings where heavy machinery, hacking or torch-applied membranes are impractical. A defining feature of the product is its three-coat, colour-coded system: each coat is supplied or applied in a contrasting shade so the applicator and the site engineer can confirm visually that full coverage and the required film build have been achieved. This single detail removes much of the guesswork that causes premature failure in liquid-applied waterproofing. For contractors and consultants in India, Roofguard sits in the sweet spot between low-cost cementitious slurries and expensive PU membranes: it delivers genuine elastomeric performance, solar-reflective light colours, and the ability to coat directly over existing brickbat coba or screed concrete that is sound but leaking. Space Arc Engineering supplies and applies Brushbond Roofguard as an authorised Fosroc distributor and applicator, with technical support for specification, surface assessment and warrantable application across Delhi NCR and Pan-India.

The technical insight

The performance of Roofguard comes from the marriage of an acrylic elastomeric binder with dispersed reinforcing fibres. The acrylic chemistry gives the cured film high elongation (around 100% per ASTM D412) so it can accommodate the daily expansion and contraction of a roof slab without splitting, while a tensile strength of about 1.10 MPa keeps the membrane robust under foot traffic and weathering. The short fibres act like rebar in concrete at micro-scale: they restrain shrinkage, improve cohesive strength, and let the coating be laid down thick (a high-build film exceeding 1 mm over three coats) without slumping or cracking as it dries. Adhesion is the other half of the equation. A reported pull-off bond of roughly 0.92 MPa (ASTM D4541) to a properly primed concrete surface means the membrane resists wind uplift and blistering. Durability data backs the field reputation: the film shows no significant change after 1000 hours of accelerated UV exposure (ASTM D4587) and a zero rating for algae and fungal growth (ASTM D5589-97), which matters in humid Indian conditions where biological staining destroys ordinary coatings. With a solids content near 70%, low water permeability (around 5.0 mm by the BS EN 12390 water-penetration method) and a measurable but breathable water-vapour transmission (about 6.0 g/m2/h per ASTM E96), the membrane keeps liquid water out while letting trapped substrate moisture escape rather than building osmotic blisters. The light, solar-reflective shades also lower roof surface temperature, easing thermal stress on both the membrane and the building below.

Where it is used

• Waterproofing of new RCC terraces and roof slabs before occupation
• Refurbishment of leaking existing roofs over sound brickbat coba or screed concrete without demolition
• Sealing of parapet walls, chajjas, sunshades and the junctions where they meet the slab
• Protective and solar-reflective coating for exposed terraces subject to light pedestrian traffic
• Overcoating of aged cementitious or bituminous waterproofing that is still adhered but no longer watertight
• Waterproofing of sloped and shell roofs where sheet membranes are difficult to lay

Key advantages

• Single component and ready to use – no on-site mixing of powder and liquid, reducing batching errors
• Colour-coded three-coat system lets engineers visually verify full coverage and film thickness
• Seamless, jointless membrane with no laps or welds that can fail like sheet systems
• Elastomeric film bridges fine shrinkage and thermal cracks while staying bonded
• Can be applied directly over sound existing roofs, avoiding costly demolition and debris removal
• Excellent UV and weather resistance with no significant change after 1000 hours accelerated exposure
• Resists algae and fungal growth, keeping light-coloured roofs clean
• Solar-reflective shades lower roof surface temperature and ease thermal load
• Applied simply by brush or roller, suitable for occupied and access-restricted buildings
• Breathable enough to release substrate vapour and resist blistering

Limitations & considerations

• Surface-applied membrane – it is not a structural crack repair and cannot bridge live or moving structural cracks beyond its elongation capacity
• Requires a sound, clean, dry and primed substrate; it will not adhere over loose, oily, laitance-covered or actively damp surfaces
• Not intended for permanent water immersion such as water tanks or swimming pools, where a tanking-grade system is required
• Designed for light foot traffic only – it is not a wearing screed and needs protection under heavy or regular traffic
• Application must be deferred during rain and below the minimum surface temperature, which can constrain the working window during monsoon
• Each coat must fully dry before the next, so the colour-coded build takes time and cannot be rushed
• Performance and warranty depend heavily on correct surface preparation, primer and achieving full film thickness

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Brushbond Roofguard

Within the Fosroc range, Brushbond Roofguard is the dedicated exposed-roof member of the Brushbond family. Standard Fosroc Brushbond is a cementitious, two-component tanking slurry suited to water-retaining and below-grade structures, whereas Roofguard is the flexible, fibre-reinforced acrylic coating made for terraces and weathered roofs; Brushbond Roofguard Premium extends the concept with a modified-polyurethane, cool-roof formulation claiming greater solar reflectance. On Indian projects Roofguard is typically specified alongside companion Fosroc products – repair mortars from the Renderoc range, joint sealants such as Nitoseal, and primers – to deliver a complete roof system rather than a single coat. Against the wider market it competes with elastomeric acrylic roof coatings such as Sika Sikalastic and Sika RainTite, Dr. Fixit Roofseal and Newcoat, STP’s Aquaseal and Tuff Coat ranges, and offerings from MBS (Maris Polymers / local elastomeric coatings). Roofguard’s clearest differentiators are its fibre reinforcement and its colour-coded three-coat thickness-verification system, which give it an honest QA advantage on site. Where a project demands very high elongation PU performance, full pedestrian-trafficable decks, or permanent immersion, a PU liquid membrane or a tanking-grade system from Fosroc or a competitor may be the better technical fit, and Space Arc Engineering will recommend accordingly rather than force-fit a single product.

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