Sopro Rapidur® B5 Rapid Drying Screed Binder

Special polymer-modified binder for particularly economical production of high-strength, rapid-set cement screeds to DIN 18 560, allowing early flooring installation. Achieves grade CT-C45-F7 after 28 days1). Low-chromate to Regulation (EC) No 1907/2 06, Annex XVII.

For the production of rapid-set bonded screeds, unbonded screeds (on separating or insulation layer) or heated screeds, allowing early flooring installation. For cement screeds to DIN 18 560 allowing early loading and flooring installation, particularly suitable for renovation and refurbishment schemes. Higher-grade screeds can also be produced. For further details, please consult our technical product information.

Sopro Rapidur® B5 Rapid Drying Screed Binder is suitable for use on heated screeds, bonded screeds, unbonded screeds and floating screeds. Particularly useful for fast-track or tightly scheduled screed laying. Site-mixed with 0–8 mm gravel sand for screeds. For use in rapid-set bonded screeds, unbonded screeds, screeds laid on an insulation layer, or heated screeds to allow early flooring installation. For renovation and refurbishment for cement screeds allowing early loading and early flooring installation to DIN EN 18 560.

Related Downloads

icon-pdf  Sopro Rapidur® B5 Rapid Drying Floor Screed Binder

icon-pdf  SMET Floor Screeds and Compounds Product Selector

icon-pdf Sopro Rapidur B5 _Sustainability Datasheet

NBSplusNBS Specification Clause

Benefits of Sopro Rapidur® B5 Rapid Drying Screed Binder

Placed screeds incorporating Sopro Rapidur® B5 are ready for tiling after approx. 3 days and ready to receive natural stone finish after approx. 5 days. The max. moisture content of ≤ CM 2.0 % must be confirmed by a required CM moisture measurement prior to flooring installation. Particularly impervious floor coverings, e.g. linoleum, PVC etc. should be laid at the earliest after 5 days or after achievement of moisture content ≤ 2.0% CM (for unheated screeds) /≤ 1.8% CM (for heated screeds).

• New, enhanced quality
• Ready for tiling after only approx. 3 days
• For fast-track or tightly scheduled screed laying
• Suitable for floor heating systems
• Long working life: approx. 2–3 hours
• May be applied in mixing ratios 1:4 and 1:5
• High resistance to moisture migration from substrate
• Suitable for renovation and refurbishment schemes
• Pumpable
• EMICODE system of GEV (German Association for control of Emissions in Products for Flooring Installation): EC1PLUS R (‘very-low-emission-plus’) rating

Technical Details for Sopro Rapidur® B5 Rapid Drying Screed Binder

Mixing RatioMixing 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 ltr water (depending on sand moisture and mortar consistency). w/c ratio 0.30–0.34.

Mixing ratio 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 ltr 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 %

MixingScreed pump or forced action mixer.
Coat ThicknessMaximum 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 LifeApprox. 2 – 3 hours1). Stiffened mortar must not be retempered by addition of water or fresh mortar to restore workability.
CoverageMR 1:4 Approx. 4.0 kg/m² per cm thickness

MR 1:5 Approx. 3.5 kg/m² per cm thickness

Strength ClassMixing Ratio 1:4

CT-C20-F4 after 1 day

CT-C35-F5 after 3 days

CT-C45-F5 after 5 days

CT-C60-F7 after 28 days


Mixing Ratio 1:5

CT-C16-F3 after 1 day

CT-C25-F4 after 3 days

CT-C30-F4 after 5 days

CT-C45-F7 after 28 days

WalkableAfter 7-8 hours1)
Ready to Recieve Floor Covering For tiling: after approx. 3 days; for impervious coverings: after 3–5 days and after achievement of residual moisture content ≤ 1.8% CM
Application TemperatureBetween +5 °C and max. +25 °C (substrate, air, material)
Floor Heating SystemsSuitable, max. flow temperature +55 °C
Minimum thickness floor heating systems25mm pipe cover
Castor Chair ResistanceSuitable (for castors to DIN 68131)
Packaging25kg bags

1) Mixing ratio: 1 : 5 (25 kg Rapidur® B5 : 125 kg 0–8 mm screed sand to DIN EN 12 620)

Available in 25kg bags, 40 bags per pallet.