MasterEmaco S 420 is a rapid setting polymer modified repair mortar for application where high compressive strengths are required. The material cures to a concrete grey colour.

Features and benefits:

  • Separate primers and bonding coats are not required allowing for complete repair in a single operation with substantial time savings.
  • Rapid-setting qualities provide high production rates saving access and labour costs.
  • High performance for extreme durability and protection of embedded reinforcement.
  • Regulation 31 approved for contact with potable water after just three days curing.
  • Can be applied 10–50 mm thick per layer.


The product is suitable for structural repairs of reinforced and non-reinforced concrete. The material is ideal for repairing damage caused by:

  • Corrosion of reinforcement bars.
  • Alkali aggregate reaction.
  • Impact damage.

It can also be used to aid bonding and application properties of hand applied repair mortars in extreme thicknesses and conditions.

Standard product features

Technical characteristics:

  • Appearance: Light grey powder.
  • Density: 1.8 g/cm³ (approximately).
  • Application temperature (ambient and substrate): 5–35°C.

- ZTV-Sib90 compliance testing (TL BE-PCC):

  • Total halogen content: ≤ 0.05 % (weight).
  • Corrosion stimulation: ≤ 10 μA/cm².
  • Corrosion resistance: ≤ 1 mm (migration of rust underneath the coating starting from uncoated edge).
  • Accelerated weathering to DIN 50017, 18 and 21: No corrosion/ delamination, ≤ 0.1 mm crack width.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-55-50/350 Repair mortar for concrete
45-55-50/345 Polymer-modified cementitious mortar

Product specification

An important note about specifying



BASF plc, Construction Chemicals


+44 (0)161 485 6222

Product reference

MasterEmaco S 420

Manufacturer details

PO Box 4,
Earl Road,
Cheadle Hulme,
Cheshire, SK8 6QG
Tel +44 (0)161 485 6222
Fax +44 (0)161 488 5220
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