Fosroc Brushbond Aquaprotect
Two-component, polymer-modified elastomeric cementitious coating engineered for potable water retaining structures – flexible, crack-accommodating and certified safe for drinking-water contact.
What is it?
A two-component, polymer-modified elastomeric cementitious waterproof coating (powder plus liquid polymer) that cures to a seamless, flexible membrane bonded directly to the substrate.
Where is it used?
Potable water tanks, overhead and underground reservoirs, swimming pools, canals, sewage and effluent structures, basements, wet areas, sunken slabs and water-retaining RCC across India.
Why use it?
It is tested and approved for contact with potable water (USFDA CFR 175-300), accommodates crack movement after immersion, and resists both positive and negative hydrostatic pressure – making it a single solution for drinking-water-grade waterproofing.
How is it applied?
Mixed with a slow-speed spiral mixer, then brush- or roller-applied in two coats of 1 mm wet film each (total approx. 1.9 kg/m2), air-cured 7 days before water immersion.
About Fosroc Brushbond Aquaprotect
Fosroc Brushbond Aquaprotect is a flexible, elastomeric cementitious waterproofing system from the well-established Fosroc Brushbond family, but engineered specifically for one of the most demanding waterproofing duties: water-retaining structures that hold drinking water. Where standard cementitious coatings are designed primarily to keep water out, Aquaprotect is formulated to perform reliably while in permanent contact with water – and, critically, to do so without contaminating that water. It is supplied as a two-part system: a cement-and-graded-aggregate powder component combined on site with a liquid acrylic polymer. When mixed and applied, the two react to form a tough, continuous membrane that bonds tenaciously to concrete, masonry and brickwork and remains flexible enough to bridge fine shrinkage and settlement cracks. For contractors, consultants and water-utility engineers in India, the defining feature is its potable-water credential: Brushbond Aquaprotect is tested and approved for use in contact with potable water as per USFDA CFR 175-300, which is what allows it to be specified inside drinking-water tanks, treated-water reservoirs and food-grade structures where ordinary bitumen or epoxy systems are unsuitable. It withstands high positive hydrostatic pressure (water pushing from inside the tank) and high negative hydrostatic pressure (ground water pushing from outside), so it protects both the water and the structure. Space Arc Engineering, as an authorised Fosroc distributor and applicator serving Delhi NCR and Pan-India, supplies Brushbond Aquaprotect with full technical and application support for water-board projects, real-estate developments and institutional buildings.
The technical insight
The performance of Brushbond Aquaprotect comes from its acrylic-polymer-modified cementitious matrix. The cement fraction provides alkalinity, adhesion and a degree of self-healing through continued hydration, while the polymer fraction reduces permeability and gives the cured film its elasticity. This combination is what distinguishes it from a rigid slurry: the film can elongate across a moving crack rather than tear at it, which is why Fosroc rates it for crack accommodation after immersion and aligns it with the crack-width philosophy of BS 8007 for water-retaining concrete. Because the membrane is breathable to vapour yet impervious to liquid water, it can be applied to green, damp or fully cured concrete and does not blister from substrate moisture or back-pressure – a practical advantage on freshly cast tanks where you cannot wait weeks for the concrete to dry. Curing chemistry matters here: the 7-day air cure before water immersion is not arbitrary, it allows the polymer film to fully coalesce and develop its elastomeric strength before being loaded by a column of water. Under hot, dry or windy Indian site conditions, moist or condensation curing is recommended to prevent the film from drying too fast and losing flexibility. The two-coat, cross-direction application builds a continuous pinhole-free membrane at roughly 1 mm dry film per coat.
Where it is used
- Internal lining of potable water storage tanks – overhead, underground and at-grade
- Treated-water reservoirs, clear-water sumps and water-treatment-plant structures
- Swimming pools and decorative water features
- Irrigation canals, channels and aqueducts
- Sewage and effluent treatment tanks and chambers
- Basement walls and rafts subject to negative (external) water pressure
- Sunken portions of toilets, bathrooms and wet areas
- Terraces, balconies and other RCC surfaces requiring a flexible waterproof membrane
Key advantages
- Tested and approved for contact with potable water (USFDA CFR 175-300) – safe for drinking-water tanks
- Resists both positive and negative hydrostatic pressure, protecting structures from internal and external water
- Elastomeric film accommodates crack movement and continues to waterproof after immersion
- Excellent bond to concrete, masonry and brickwork – no separate primer membrane required in most cases
- Can be applied to green, damp or fully cured concrete, so work can start without long drying delays
- Seamless, brush/roller-applied membrane with no joints, laps or seams to fail
- Breathable to water vapour, reducing the risk of blistering from substrate moisture
- Non-toxic and non-tainting once cured; supplied in convenient pre-batched packs
Limitations & considerations
- Not a structural or crack-injection product – large, live or moving structural cracks must be treated separately before coating
- Minimum application/substrate temperature of around 5 C; not suitable for application onto frozen or frosted surfaces
- Requires a sound, clean, laitance-free substrate – poor surface preparation is the most common cause of failure
- Pot life is limited (about 2 hours at 20 C, around 1 hour at 35 C), so material must be mixed in workable batches
- Mandatory 7-day air cure before water immersion or filling – the structure cannot be put into service immediately
- As a coating it is not designed for permanent exposure to heavy foot or vehicular traffic without protection
- Curing must be controlled in hot/dry Indian conditions or the film can dry too fast and lose flexibility
Selection & best practice
Success with Brushbond Aquaprotect is decided at the substrate. Prepare concrete to a sound, clean, laitance-free finish, repair honeycombing and form coving fillets at all wall-to-floor junctions before coating. Pre-saturate the surface to a saturated-surface-dry (SSD) condition – damp but with no standing water – so the coating bonds without the substrate sucking water out of the film. Mix only what can be used within the pot life by gradually adding powder to liquid under a slow-speed spiral mixer (3-5 minutes) to a lump-free consistency; never add extra water. Apply two coats by stiff brush or roller in mutually perpendicular directions, allowing the first coat to set (typically 4-16 hours at 20 C) before the second, and reinforce stress points – construction joints, corners and pipe penetrations – with a fibre-mesh band embedded between coats. After the final coat, air-cure for a full 7 days, using moist or condensation curing in hot or dry weather, before immersing or filling the structure. For potable tanks, flush thoroughly before commissioning.
Specifications
| Product type | Two-component, polymer-modified elastomeric cementitious waterproof coating |
| Components | Powder (cement / graded aggregate) + liquid acrylic polymer |
| Colour | Grey and white |
| Potable water approval | Tested / approved for contact with potable water – USFDA CFR 175-300 |
| Number of coats | 2 coats |
| Wet film thickness | ~1 mm per coat (2 coats) |
| Consumption | ~1.9 kg/m2 total for two coats |
| Coverage (15 kg pack) | ~7.5 m2 at 1 mm (two coats) |
| Pot life | ~2 hours at 20 C; ~1 hour at 35 C |
| Overcoat interval | 4-16 hours at 20 C, 50% RH |
| Cure before water immersion | 7 days air cure |
| Min. application temperature | 5 C |
| Hydrostatic resistance | Withstands high positive and negative hydrostatic pressure |
| Crack accommodation | Accommodates crack movement after immersion (aligned with BS 8007 crack-width philosophy) |
| Substrates | Green, damp or cured concrete; masonry; brickwork |
| Pack sizes | 15 kg (approx. 11.75 kg powder + 3.25 kg liquid); 5 kg pack also available |
| Shelf life | 12 months unopened, in cool dry store |
Industry use cases
Municipal / Water Utilities
Lining of treated-water reservoirs, clear-water sumps and overhead service reservoirs where the coating must be certified safe for potable water and resist negative ground-water pressure.
Real Estate / Residential
Waterproofing of underground and overhead domestic water tanks in apartment complexes and gated communities, plus sunken bathrooms and basements.
Hospitality / Recreation
Swimming pools, decorative water bodies and spa structures requiring a flexible, crack-bridging, non-tainting waterproof membrane.
Infrastructure / Irrigation
Canals, channels and aqueducts where long runs of concrete need a continuous, immersion-stable coating that accommodates thermal and settlement movement.
Industrial / Process
Sewage, effluent and process-water tanks where a tough cementitious membrane protects the RCC from constant immersion and aggressive water.
Healthcare / Food & Beverage
Hygiene-critical water-storage and wash-down structures in hospitals and food-processing plants needing a non-toxic, drinking-water-grade lining.
Frequently asked questions
Is Fosroc Brushbond Aquaprotect safe for drinking water tanks?
How much Brushbond Aquaprotect do I need per square metre?
Can it be applied to a freshly cast or damp concrete tank?
How long before the tank can be filled with water?
How does Brushbond Aquaprotect differ from standard Brushbond or Brushbond RFX?
What surface preparation does it need?
Does Space Arc Engineering supply and apply Brushbond Aquaprotect across India?
How we position Fosroc Brushbond Aquaprotect
Within the Fosroc range, Brushbond Aquaprotect sits at the potable-water end of the Brushbond family. If a project needs general flexible waterproofing for terraces, walls or wet areas, the standard Fosroc Brushbond or the higher-build Brushbond RFX / UltraFlex are the usual choices; Aquaprotect is the specialist you reach for when the structure holds drinking water and the coating itself must be certified non-tainting. It pairs naturally with other Fosroc systems on the same job – Conbextra grouts for honeycomb and tie-hole repair, Renderoc for substrate reinstatement, Nitoseal / Nitobond for joints and bonding, and Proofex membranes where a sheet system is preferred below grade. Against the wider Indian market, credible alternatives in the cementitious-elastomeric and water-retaining space include Sika (Sikalastic / SikaTop Seal and the Sika potable-water-approved coatings), MBS / MYK (their flexible cementitious coatings), Dr. Fixit (Pidilite, e.g. Fastflex and Roofseal type systems), and STP (Sika-STP / Shalimar). Many of these compete strongly on price and availability; Aquaprotect’s differentiator is the combination of genuine potable-water certification, dual positive/negative hydrostatic resistance and after-immersion crack accommodation under one well-supported Fosroc system. For consultants writing specifications, the honest position is to match the certification to the duty – for drinking-water and pool linings, Aquaprotect or an equivalently potable-certified product should be specified rather than a general-purpose coating. Space Arc Engineering can advise on the right Fosroc product and supply genuine material across Delhi NCR and Pan-India.
Related Waterproofing products
Source Fosroc Brushbond Aquaprotect for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.