A light-duty, self-levelling underlayment for application before floor finishes, e.g. tiles, carpets and vinyl sheeting. Suitable for foot traffic and light commercial areas.

General information

Uniclass 2015

Pr_35_31_06_80 Smoothing and levelling underlay compoundsPrimary


M10/12 Proprietary polymer modified levelling screeds

M10/160 Proprietary self smoothing levelling screeds

M10/17 Proprietary polymer modified wearing screeds

M10/192 Proprietary self smoothing wearing screeds

M40/460 Smoothing underlayment

M42/10 Wood flooring

M42/110 Wood block flooring

M50/460 Smoothing/ levelling underlayment compound

M50/65 Laying coverings

Specification data - Smoothing and levelling underlay compounds

Product Reference

Cemtop UL


Nitoprime 33, two coats

Screed thickness

5–50 mm. Consult Fosroc for recommendations.

Standard product features


Nitoprime 33 is an aqueous acrylic copolymer.

CE marking:

  • Declaration of Performance: UK9-197.
  • Standard: BS EN 13813:2002.
  • Compressive strength: >20 MPa.
  • Flexural strength: >4 MPa.
  • Fire resistance: NPD.


  • Compressive strength (at 28 days, BS EN 13892-2:2002): 20 N/mm².
  • Flexural strength (at 28 days, BS EN 13892-2:2002): 4 N/mm².
  • Bond strength (at 28 days, BS EN 13892-8:2002): 1.0 N/mm².

Traffic time at 20º:

  • Light traffic: 4 hours.
  • Heavy traffic: 36 hours.

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