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RIW Cementfill HB


Single component cementitious high build mortar.

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  • A waterproof mortar for the structural repair, rendering and profiling of vertical, horizontal and overhead surfaces.
  • The product can also be used to provide ‘fillets’ at internal corners prior to application of other RIW Limited membranes.


A single component cementitious high build mortar, which incorporates the most advanced cement chemistry, microsilica, fibre and styrene acrylic copolymer technology.

Features and benefits:

  • A rapid hardening, low density, high strength mortar with enhanced polymer properties.
  • The thixotropic, shrinkage compensated nature of the product enables easy high build trowel applications.
  • Subject to normal conditions of use, the product will provide an effective barrier to the transmission of liquid water for the life of the structure.
  • Dense matrix offers low permeability to water, even at 10 bar pressure.
  • High bond strength exceeds the tensile strength of concrete, thus ensuring monolithic performance of the repair.
  • Excellent low sag properties.
  • Non-toxic when cured.
  • Apply by float or trowel as a render.


  • The areas to be treated must be free from all unsound material, i.e. dust, oil, grease, corrosion by-products and organic growth.
  • The strength of the concrete sub-base should be a minimum of 20 N/ mm².
  • The product is highly polymer modified and as a result concrete surfaces do not generally require a primer.
  • Highly porous substrates should be primed with RIW Cementseal Primer.

Application rate:

  • Normal applications: 2.6–3.0 litres of clean water per 20 kg bag, depending upon desired consistency.
  • High build applications: 2.8 litres of clean water per 20 kg bag.

Application temperature:

  • 5–35°C.
  • Protect the mortar from strong sunlight and drying winds.


Protect the mortar from strong sunlight and drying winds with RIW Cementseal Primer, polythene sheeting, damp hessian or similar.

General information







20 kg



Pr_20_31_53_30 Fibre-reinforced polymer-modified cementitious mortarsPrimary


M20/19 Proprietary cement gauged render

M20/160 Proprietary cement gauged render

Specification data - Fibre-reinforced polymer-modified cementitious mortars

Product Reference

RIW Cementfill HB

Application thickness

5–80 mm per layer. Ensure that an initial 5–10 mm thickness of mortar is well placed and adhered before building up to larger depths.

The application thickness achievable is dependent upon the substrate.


Concrete grey.


48 N/ mm² (after 28 days); Class R3 ≥ 25 MPa.

Reaction to fire

Euroclass A2-s1, d0.


RIW Cementfill HB

RIW Cementfill HB