Class R4 Waterproof Screed & Pore Filler (EN1504-3, DWI 31, WRAS)


Monolevel 844SP is a fully waterproof, engineering quality fairing coat for filling minor blow holes and defects, and for repairing surface cavities and honeycombed concrete. Monolevel 844SP can be used in thin screed applications to level both vertical and horizontal concrete surfaces and to reinstate cover while providing a fair faced anti-carbonation finish.

Monolevel 844SP is a single component, thixotropic, polymer modified, cementitious repair mortar with high adhesive properties, allowing it to be used as a waterproof screed, as well as a filler, for filling minor voids and defects to provide a fair faced finish. It incorporates the most advanced microsilica, polymer and fibre technology, curing to provide high waterproofing properties, excellent protection from acid gases, chlorides and freeze/thaw cycles as well as enhanced chemical resistance. The product is supplied as a single component system requiring only the addition of clean water.


  • Incorporates the latest proven cement chemistry, microsilica, fibre and styrene acrylic copolymer technology
  • Pre-packaged material requiring mixing with clean water on-site to give an adhesive mortar which can be rapidly applied in vertical, horizontal and overhead situations
  • High bond strength exceeds tensile strength of concrete thus ensuring monolithic performance of the repair
  • Dense matrix offers low permeability to water, even at 10 bar pressure, and very high diffusion resistance to acid gases and chloride ions
  • Non-toxic when cured and is listed as authorised under Regulation 31 for use in the supply of drinking water
  • Economic mortar requiring no substrate or inter-layer priming. Part bags can be mixed. Suitable for feather edging
  • Easily overcoated with specialist membranes to provide further protection and aesthetic quality.


CE marked in accordance with BS EN 1504 Part 3. Fully complies with the Highways Agency Standard BD 27/86 for the repair of Highway Structures. Listed under DWI Regulation 31 for drinking water applications. Compliant with LU Standard 1-095 ‘Fire Safety Performance of Materials’.

Specification Clause

The fairing coat shall be a single component, waterproof, thixotropic, polymer modified cementitious repair mortar with high adhesive properties. It shall be CE marked in accordance with BS EN 1504-3 Class R4 and shall comply with the following performance specification:

  • Compressive strength at 20°C of at least 23 MPa in 1 day and 60 MPa in 28 days
  • Flexural strength at 28 days (20°C & 65% R.H) of at least 10.5 MPa in accordance with BS 4551
  • Impermeable to water under 10 bar hydrostatic pressure such that 1mm of mortar is equivalent to 1000mm of concrete
  • Oxygen diffusion coefficient to be no greater than 2.72 x 10-4 cm2/sec, such that a 6mm coating is equivalent to 250mm of concrete cover.
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