ARDEX S 21 Rapid Hardening Floor Tile Bedding Mortar

A rapid setting, pourable mortar for bedding floor tiles in external and internal situations, which can be grouted and subjected to loads three hours after fixing at normal temperatures.

Where large flat backed tiles and smooth backed, dense and fully vitrified ceramics are to be fixed, it is recommended that ARDEX S 21 is used in conjunction with ARDEX E 90 admix. Can be used with sharp sand to form screed falls from 30 mm down.

General information


For fixing floor tiles, pavers, natural stone, etc; Versatile - use with sharp sand to form ramps and pre-level subfloors; Internal or external applications; Fluid/pourable consistency - solid bedding easily achieved; Rapid hardening - grout and walk on after 3 hours


Cementitious adhesive

Uniclass 2015

Pr_20_31_02_26 Epoxy resin-based adhesivesPrimary


M40/110 Tiling to

M40/120 Mosaic to

M40/20 Existing backgrounds/ bases generally

M40/320 Existing concrete/ screeds

M40/350 Existing tiles

Show more
Specification data - Epoxy resin-based adhesives

Product Reference

ARDEX S 21 Rapid Floor Tile Bedding Mortar

Product Options

Bedding/ Fixing:

Solid adhesive; consult ARDEX’s technical literature for details and fixing guidance.

Digital objects
PlatformCompatibleVersionCertified to
Revit 2016 1 1.3
- 1 1.3
Download now from NBS National BIM Library
Similar products from Ardex Ltd – Flooring, Tiling & Screeding products