Rockbond Lightweight Screed (RB LWS)

Product Information Sheet:


ROCKBOND LIGHTWEIGHT SCREED (RB LWS) powders are premixed, low density, ready to use, cementitious screed powders.  The compounds consist of blends of cement powders, shrinkage compensating agents, graded lightweight sands and aggregates and a combination of compatible admixtures.  The powders, when mixed with water, produce lightweight, free flowing concrete screeds, which are easily mixed, pumped and placed.  The screeds are used as low density, low strength materials to fill large volume voids, for lightweight floors and for low density trench fill.  ROCKBOND LIGHTWEIGHT (1100) SCREED (RB LW1100S) has a set density of 1100kg/m3, and the ROCKBOND LIGHTWEIGHT (1250) SCREED (RB LW1250S) has a set density of 1250kg/m3.  The powders are packaged in 25kg moisture proof, durable bags and have a shelf life of 5 years.

Special Properties

  • Quickly and easily mixed with water, pumped and placed.
  • Portland cement based, shrinkage compensated, microsilica enhanced.
  • Lightweight: can be designed and supplied with set densities from 750kg/m³ to 1800kg/m³.
  • Free flowing, self compacting, self smoothing and will not readily segregate or bleed.
  • Excellent insulator: a poor conductor of heat and sound.
  • Resistant to fire: will protect steel against fire and heat, and will not burn or give off toxic gases.
  • Contains no chlorides, alumina cement or deleterious substances.
  • Very high yielding and economical to use.
  • Non flammable, non toxic, odour free, user friendly and safe to use.


  • Whenever a free flowing, low density, low strength material is required.
  • For the installation of lightweight floors and lightweight floor toppings.
  • To fill large volume voids with a lightweight material.
  • For use as a free flowing, low density, low strength trench fill.
  • For the casting and installation of lightweight concrete structures.
  • To fill areas that require a low heat material.
  • To thermally insulate buildings and walls on the inside or outside.
  • To protect steel and concrete structures from fire and heat.
  • For use as an insulating infill around pipes and ducts.
  • For lightweight mezzanine floors, cavity walls, roofs and spaces.
  • To minimise condensation on walls and ceilings.
  • To acoustically insulate rooms or areas to reduce noise and sound.