• Over 6000 productsOver 6000 products
  • Next Day Delivery on orders confirmed before 2pmNext Day Delivery on orders confirmed before 2pm
  • 8 depots for national coverage8 depots for national coverage
Product Information
Technical Datasheet
Safety Datasheet


ROCKBOND UNDERWATER MORTAR (RB UWM) powder is a blend of special cement powders, high quality graded sands and an unique combination of polymers and admixtures. The powder, when mixed with water, produces a mortar which is wash-out resistant and waterproof. The material develops a high early strength, and can be used above or below the waterline.

Features & Benefits:

  • Portland cement based, polymer modified and microsilica enhanced.
  • The mortars develop an excellent putty consistency for ease of application.
  • Can be used above and below the waterline.
  • Will not disperse, wash-out or break up underwater.
  • Strong, impermeable bond to brick, stone, masonry, steel and concrete.
  • Mortars can be built up to a level of existing profiles in one operation.
  • The mortar can be finished to produce a smooth and attractive surface.
  • The material will not contaminate canals, rivers, reservoirs or lakes.
  • The powder contains no iron, high alumina cement, chlorides or deleterious substances.
  • High yielding, economical, non flammable, non toxic, odour free, user friendly and safe to use in underwater environments.


  • Offshore locations and underwater applications.
  • To repair and waterproof precast concrete, tunnels, culverts, sewers and pipes.
  • To point and repair bricks, blocks and masonry above and below the waterline.
  • The repair of concrete in tidal zones where time is limited.
  • The protection of marine structures above and below the waterline.
  • The consolidation of sea defences, harbours, jetties, docks and locks.
  • Caulking material for gaps and joints, and for sealing shutters.
  • In situations where a quick, early strength gain is required.
  • To instantly stop and plug the flow of running water or grout through brick or concrete.