About Fosroc Brushbond R

Fosroc Brushbond R is a two-component, acrylic polymer modified cementitious coating engineered to waterproof and protect concrete and masonry. The kit pairs a powder component of specially selected cements, graded hard-wearing aggregates and additives with a liquid component of blended acrylic co-polymers and wetting agents. On site only clean water is added, producing an easily brushable slurry that can also be rolled, sprayed or trowelled. Once cured it forms a seamless, tightly bonded film that behaves like a thin cementitious skin reinforced with polymer, rather than a loose sheet membrane.

The “R” grade sits at the practical, workhorse end of the Brushbond family. It is the standard cementitious coating intended for sound substrates with little or no structural movement, where the priority is a durable, breathable barrier against water and corrosive salts. It is the natural choice for water-retaining structures and below-grade tanking where a rigid, monolithic coating bonded to the concrete is preferred. Where the structure is prone to dynamic cracking or thermal movement, Fosroc’s more elastomeric grades such as Brushbond RFX and Brushbond UltraFlex are specified instead, while Brushbond R remains the economical option for stable concrete and masonry.

For specifiers in India, the appeal of Brushbond R is that it does three jobs in one product. It is a positive-side waterproofer that resists hydrostatic pressure up to a 7-metre head depending on thickness; it is an anti-carbonation and anti-chloride coating that shields embedded steel in aggressive coastal and industrial air; and because it is non-toxic, it is suitable for the inside faces of potable water tanks. It bonds directly to damp concrete and masonry with minimal surface preparation, which keeps labour costs down on large surface areas such as terraces, tank walls and basement rafts.

The technical insight

Brushbond R is best understood as a polymer-modified cementitious (PMC) coating, not a flexible elastomeric membrane. The acrylic co-polymer in the liquid component reduces the water/cement ratio needed for workability, plugs capillary pores and dramatically improves adhesion and toughness, so the cured film resists water ingress and carbonation while remaining vapour-permeable (breathable). This is why it can sit on damp concrete and let residual moisture escape without blistering, a critical difference from impermeable bituminous or PU membranes that can trap vapour and debond. Fosroc’s published data show it acts as a significant barrier to chloride (stopping a minimum of around 92% of chloride ions versus an uncoated substrate) and gives a marked reduction in carbonation depth, which is the core mechanism by which it protects reinforcement and extends service life of RCC. The trade-off is movement accommodation: as a rigid PMC the R grade bridges only fine, static shrinkage cracks. Live cracks, construction joints and zones of structural movement must be detailed separately (fillets, jointing tape, or a more elastomeric Brushbond grade) because the rigid film will track a moving crack. Correct dry film thickness is the other governing variable, hydrostatic resistance and chloride/carbonation performance are both thickness-dependent, so achieving the full 2 mm where pressure or exposure is high is non-negotiable for the rated performance.

Where it is used

• Internal and external waterproofing of RCC and masonry water tanks and overhead/underground reservoirs, including potable water tanks (non-toxic)
• Basement, lift pit and retaining wall tanking against positive water pressure up to ~7 m head, thickness dependent
• Roof slabs, terraces and chajjas as a breathable waterproof and protective coating
• Toilets, bathrooms, kitchens, balconies and other wet areas before tiling
• Anti-carbonation and anti-chloride protection of atmospherically exposed concrete in coastal and industrial environments
• Sealing and re-facing of leaking brick, block and masonry walls, evening out honeycombed or pitted concrete
• Swimming pools, water channels, drainage culverts and similar water-contact concrete surfaces

Key advantages

• Excellent barrier to water, chloride ions and carbon dioxide, protecting embedded reinforcement and extending structure life
• Breathable, allows water vapour to escape so it can be applied to damp substrates without blistering
• Non-toxic when cured, suitable for the inside of potable water tanks
• Resists positive hydrostatic pressure up to a 7-metre head depending on applied thickness
• Strong adhesion to damp concrete, brick and block, on both new and existing structures, with minimal surface preparation
• Seamless and monolithic, with no laps or joints to fail, unlike sheet membranes
• Versatile application by stiff brush, roller, spray or trowel; low labour cost on large areas
• Good long-term weathering and UV resistance for exposed exterior surfaces
• Effectively covers honeycombed and pitted poured concrete and bridges fine static shrinkage cracks

Limitations & considerations

• A rigid cementitious coating, it bridges only fine static shrinkage cracks; for dynamic or live cracking specify the more elastomeric Brushbond RFX or UltraFlex
• Rated waterproofing and protection depend on achieving the correct dry film thickness (typically up to 2 mm); thin or uneven application reduces performance
• Must be applied to clean, sound substrate; spalled, friable or contaminated concrete needs prior repair with a Renderoc mortar
• Short pot life once mixed (about 30 minutes at 27 C, 70 minutes at 20 C), so only mix what can be used in time and do not re-temper with water
• Do not apply when substrate temperature is below 5 C, in driving wind/dust, or where frost is likely within 48 hours; avoid where relative humidity exceeds ~90%
• Construction joints, junctions and live movement joints need separate detailing and are not covered by the coating alone
• Not a structural product; it protects and waterproofs but does not add load capacity or replace proper structural crack repair

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Brushbond R

Within the Fosroc range, Brushbond R is the value-engineered, rigid member of the Brushbond waterproofing family. It pairs naturally with Renderoc repair mortars and Renderoc Plug for substrate preparation and water stopping, and with Nitobond acrylic bonding agents on the same projects. Step up to Fosroc Brushbond RFX or Brushbond UltraFlex when the structure needs genuine crack-bridging and elastomeric movement accommodation, and consider Fosroc Roofguard or a Proofex membrane where a different roof or below-grade system is preferred. Against the wider Indian market, Brushbond R competes with two-component acrylic-cementitious coatings such as Sika SikaTop Seal-107 and Sika Lite-based systems, MBS (MYK) coatings, Dr. Fixit Pidiproof LW+ and Dr. Fixit Roofseal/Newcoat type acrylic systems, and STP’s polymer-modified cementitious waterproofing range. Its edge is the combination of proven anti-carbonation/anti-chloride data, potable-water suitability and the support of an established Fosroc applicator network; its limitation versus premium elastomeric coatings is movement accommodation, which is exactly why it should be specified for stable substrates and the flexible grades reserved for cracking-prone areas. As an authorised Fosroc distributor and applicator serving Delhi NCR and Pan-India, Space Arc Engineering can advise on the right Brushbond grade, supply genuine material and support correct application.

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