Fosroc Brushbond Ultra Flex — Flexible Cementitious Waterproofing Coating (25 kg)

A rigid waterproofing coating fails the moment the structure it's protecting moves. Concrete shrinks, expands and contracts with temperature, takes thermal stress on roof slabs exposed to sun, and develops hairline cracks over its service life — and any waterproofing layer that can't accommodate that movement will tear at exactly the points where water needs to be kept out most. This is why flexibility is no longer an optional feature in cementitious waterproofing, it's the defining one. Fosroc Brushbond Ultra Flex from Fosroc Chemicals India Pvt. Ltd. is the polymer-modified flexible cementitious coating built around that principle, and it's reached for on projects where the waterproofing has to move with the substrate rather than fight against it.

Brushbond Ultra Flex is a two-component system — a cementitious powder paired with a polymer liquid that gets mixed on site to form a brushable waterproofing slurry. The polymer modification is what gives the cured film its elastomeric behaviour. Once applied in two coats over a prepared substrate, it forms a continuous membrane that bonds chemically to concrete and masonry, resists water under positive and limited negative pressure, and stretches across hairline cracks that develop after application without tearing. That crack-bridging capability is the practical difference between a waterproofing job that holds and one that telegraphs every structural movement as a leak.

The applications it has earned its place in are the ones where movement and water exposure happen together — roof terraces and balconies taking full sun and rain cycles, sunk slabs in bathrooms and toilets, water tanks both potable and non-potable, swimming pools, basement retaining walls where positive-side waterproofing is possible, retaining structures and planter boxes. Applicators and contractors trust it because the mixing ratio is straightforward, brush application doesn't demand specialist equipment, and the polymer-cementitious chemistry adheres to damp substrates — which on Indian sites, where genuinely dry concrete is the exception rather than the rule, matters more than the technical datasheet alone suggests.

A construction chemical from Fosroc Chemicals India Pvt. Ltd. engineered for waterproofing where flexibility and adhesion both matter — Brushbond Ultra Flex is the flexible cementitious specification for terraces, water tanks, bathrooms and any substrate where a rigid coating won't survive the structure's own movement.