Home > Companies > SMET Building Products Ltd > Sopro Rapidur® B5 Rapid Drying Screed Binder

A special polymer-modified binder for use in rapid-set cement screeds allowing early flooring installation, based on DIN 18 560. Low-chromate to Regulation 1907/2006/EC, Annex XVII.

Features/ Benefits:

  • Ready for tiling after only approximately three days.
  • For fast-track or tightly scheduled screed laying.
  • Suitable for floor heating systems.
  • Good workability.
  • Pumpable.
  • For indoor and outdoor use.
  • Tested to CT-C60-F7 DIN EN 13813.

Standard product features

Technical characteristics:

  • Colour: Cement grey.
  • Coat thickness: Maximum and minimum screed thickness depends on incorporated aggregate. Screed should be at least three times and at most ten times as thick as maximum particle diameter of aggregate. Recommended grading of screed aggregate 0–8 mm; coat thickness approx. 25–80 mm.
  • Pot life: Approx. 2–3 hours. Stiffened mortar must not be retempered by addition of water or fresh mortar to restore workability.
  • Walkable: After 7–8 hours.
  • Ready to receive floor covering: For tiling: after approx. three days; for impervious coverings: after 3–5 days and after achievement of residual moisture content ≤1.8% CM.
  • Application temperature: Between 5–25°C.
  • Floor heating system: Suitable (maximum flow temperature: +55°C).
  • Minimum thickness for floor heating systems: 25 mm pipe cover.
  • Castor chair resistance: Suitable (for castors to DIN 68131).


Mixing ratio:

  • 1:4: 25 kg Sopro Rapidur® B5 : 100 kg 0–8 mm screed sand to DIN EN 12 620 (15 shovelfuls) : 7.5–8.5 L water (depending on sand moisture and mortar consistency). w/c ratio 0.30–0.34.
  • 1:5: 25 kg Sopro Rapidur® B5 : 125 kg 0–8 mm screed sand to DIN EN 12 620 (20 shovelfuls) : 9.0–10.0 L water (depending on sand moisture and mortar consistency). w/c ratio 0.36–0.40.

Particle distribution (grading curve) for aggregate (screed sand) shall fall within A8/B8 range under DIN 1045 Part 2, Annex L, Diagram L.1, and shall exhibit an adequate, though not overly high proportion of fine sand; percentage passing a 0.25 mm sieve: approx. 7–10 %.


  • Mixing ratio 1:4: Approximately 4.0 kg/m² per cm thickness.
  • Mixing ratio 1:5: Approximately 3.5 kg/m² per cm thickness.

Strength class:

- Mixing ratio 1:4:

  • CT-C20-F4 after one day.
  • CT-C35-F5 after three days.
  • CT-C45-F5 after five days.
  • CT-C60-F7 after 28 days.

- Mixing ratio 1:5:

  • CT-C16-F3 after one day.
  • CT-C25-F4 after three days.
  • CT-C30-F4 after five days.
  • CT-C45-F7 after 28 days.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-55-10/370 Polymer modified levelling screed mix
45-55-10/380 Quick drying levelling screed mix

Product specification

An important note about specifying



SMET Building Products Ltd


+44 (0)28 30266833

Product reference

Sopro Rapidur® B5 Rapid Drying Screed Binder

Manufacturer details

93A Belfast Road,
Co Down, BT34 1QH
Tel +44 (0)28 30266833
Fax +44 (0)28 30267619
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