About Fosroc Hydroproof Xtra

Hydroproof Xtra is Fosroc’s economical answer to everyday surface waterproofing where a full elastomeric membrane would be overkill. It arrives as a single liquid component: an acrylic polymer emulsion that the applicator gauges with ordinary Portland cement right at the workface. That on-site blend is what sets it apart from ready-mixed systems. You carry only the liquid to site, buy cement locally, and mix precisely the quantity each pot life allows, which keeps wastage and logistics costs low on large horizontal areas like terraces and podium decks.

Once brushed on and cured, the acrylic-cement composite hardens into a continuous film that resists water absorption to a maximum of 1 percent while still letting trapped vapour escape from the slab beneath. That breathability matters on Indian roofs, where an over-sealed surface can blister as day heat drives moisture upward. The coating bonds to concrete at roughly 1 N/mm2, tolerates both horizontal and vertical work, and stays non-toxic and non-flammable throughout, so it suits occupied buildings, water-retaining structures and food-adjacent tanks without the solvent hazards of bituminous alternatives.

The technical insight

The waterproofing action is a two-part story. The acrylic polymer is the flexible, film-forming binder; the cement you add is the reactive filler that hydrates and stiffens the matrix. When gauged at the specified 1:2 liquid-to-cement ratio, the polymer particles coalesce as the water leaves and the cement sets, knitting into a dense, pore-blocking skin that is far less permeable than the bare substrate. Because the polymer stays in the film, the coating retains a degree of flexibility that neat cement slurry never would, letting it accommodate minor substrate movement and hairline surface stress rather than cracking rigidly. The priming coat, thinned with water and richer in cement, penetrates and grips the prepared concrete first, giving the topcoats a compatible, well-keyed base. Moist curing after the final coat is not optional housekeeping; it lets the cement fraction hydrate fully so the composite reaches its designed density and adhesion before it ever meets standing water.

Where it is used

• Waterproofing roofs, terraces and balconies as a sandwich layer beneath a sloping screed or protective plaster
• Coating pools and fountains where a breathable, non-toxic surface treatment is required
• Lining reservoirs, water channels and similar retaining structures
• Protecting rain-exposed end walls and parapets from driving water
• Surface waterproofing of concrete and masonry in basements and wet areas
• Cost-effective waterproofing of large horizontal decks where site-gauged material reduces wastage
• Refurbishment coating over sound, cleaned concrete that has lost its original water resistance
• Protective coating shielding concrete and mortar from wind, rain and sunlight

Key advantages

• Single liquid component gauged with locally bought cement, cutting material and transport cost
• Water-based, non-toxic and non-flammable, safe for occupied and water-retaining structures
• Breathable film lets internal water vapour escape, reducing blistering on hot roofs
• Brush-applied on both horizontal and vertical surfaces with ordinary site tools
• Excellent adhesion to concrete and masonry at approximately 1 N/mm2 bond strength
• Low water absorption of 1 percent maximum once cured
• Retains acrylic flexibility rather than setting brittle like neat cement slurry
• Can be pigmented with white cement and compatible pigments for a coloured finish

Limitations & considerations

• Requires on-site mixing with cement and a mixing paddle, so quality depends on correct gauging and mix discipline
• Short 30-minute pot life at 30C means only small batches can be prepared at a time
• Cannot be applied below 10C, limiting cold-weather or high-altitude winter work
• Demands disciplined moist curing plus a three-day dry period before water submersion
• Not a high-elongation membrane for structural crack-bridging or heavy movement joints
• Surface preparation is critical; oil, laitance or unsound concrete will compromise adhesion

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Hydroproof Xtra

Position Hydroproof Xtra as Fosroc’s economical, site-gauged entry point for waterproofing sound concrete and masonry, ideal where budget and simple logistics matter more than high elongation. When a project needs a factory-formulated, higher-performance flexible membrane with genuine crack-bridging, step up within the Fosroc family to Brushbond or Brushbond RFX. For integral protection of the concrete itself, pair it with Fosroc’s Conplast waterproofing admixture range, and for active leaks or construction joints use Renderoc plugging mortars and Supercast waterstops. Across our other brands, comparable acrylic-cementitious coatings include Dr. Fixit and Asian Paints SmartCare systems, which our team can specify where availability or client standardisation calls for an alternative.

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