Repair Systems — 01
Self-levelling screed systems — balcony waterproofing
Technical product reference for self-levelling screed systems used in balcony and terrace waterproofing remediation. Covers internal vs external use, pre-membrane substrate preparation, product selection, application limitations, and brand comparisons for Australian Class 2 strata building applications.
What are self-levelling underlayments?
Self-levelling compounds (SLCs) are pourable, free-flowing cement-based underlayments that smooth and level a substrate before tiling, resilient flooring or a coating. They are mostly interior smoothing compounds, though some grades are exterior-rated for balconies and terraces. They smooth and level — they do not waterproof or create falls. Selection turns on interior vs exterior rating, thickness range, drying speed, and the primer and finish compatibility.
Product Reference
Individual products — one card each — scroll to view all
ARDEX Australia
ARDEX K 301
Exterior-rated cement self-levelling & smoothing compound
ARDEX K 301 is a robust cement-based self-levelling and smoothing compound for interior and exterior use, engineered to withstand sun, rain, heat, cold and freeze-thaw — making it suitable for balconies and terraces. Usable 2–20 mm before the floor finish.
ARDEX Australia
ARDEX LQ 92
Cement-based self-smoothing undertile levelling underlay
ARDEX LQ 92 is a cement-based undertile levelling underlay — mixed with water it is smooth, pourable, free-flowing and self-smoothing, applied from a feather edge up to 25 mm to level uneven concrete floors prior to tiling.
ARDEX Australia
ARDEX K 15 Microtec
Rapid-drying interior self-levelling underlayment
ARDEX K 15 Microtec is a rapid-drying cement-based interior self-levelling smoothing underlayment (Microtec technology) for smoothing and levelling before resilient, tile and other floor finishes. Confirm the thickness range and primer against the current Ardex Australia TDS.
Mapei Australia
Mapei Ultraplan Eco
Ultra-quick-hardening self-levelling smoothing compound (low-VOC)
Mapei Ultraplan Eco is a self-levelling, ultra-quick-hardening, low-emission smoothing compound for interior thicknesses from 1 to 15 mm, used to smooth and level before resilient, tile and other floor finishes.
System Comparison
Self-levelling underlayments — confirm all selections against the current manufacturer TDS before specifying.
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Do not confuse self-levelling screeds with:
- Polymer-modified sand-cement screeds (ARDEX A 38, A 48, Mapecem Pronto, Topcem Pronto AU) — these are compacted screeds suitable for pre-membrane falls correction and over-membrane unbonded toppings — listed on the polymer-modified screed page
- Internal self-levelling compounds (ARDEX K 15 Microtec, Mapei Ultraplan Eco, Ultraplan Maxi) — these are for internal use only and must not be used on external balconies under any circumstances
- Over-membrane protection toppings — self-levelling compounds are not approved for application over liquid-applied waterproofing membranes — only A 38 / A 48 unbonded over a slip sheet is approved for this position in ARDEX systems
- Waterproofing membranes — self-levelling screeds are substrate preparation products, not waterproofing — a classified membrane must always be applied above the screed
- Tile adhesive beds — a tile adhesive bed is applied over the cured membrane, not over a self-levelling screed directly — confirm the correct system sequence
Disclaimer
This page provides general technical information only. Final product selection must be confirmed against the current manufacturer technical data sheet, project specification, substrate condition, substrate moisture content, membrane system requirements, NCC requirements, AS 3740 fall requirements, and applicator warranty conditions. Do not rely on this reference as a substitute for professional engineering or waterproofing consultant advice.