Balcony Waterproofing Sydney

AS 4654.2 compliant with flood-test verification and a 10-year workmanship warranty.

Why Sydney Balconies Fail — and How We Fix It

Sydney’s climate — intense storms, UV exposure, and wide thermal swings — degrades any balcony membrane not installed to specification. When water gets through, it travels into the slab, corrodes steel reinforcing, and appears as ceiling stains in the room below.

Econyc uses liquid polyurethane membranes that stay elastic across Sydney’s full temperature range. Every job includes a 24-hour flood test before any tiling proceeds — the only way to verify the membrane before it’s hidden under tiles.

Our AS 4654.2 Compliance Process

Falls to Drains

Minimum 1:100 fall verified under the membrane. Sand-cement screed or Ardex used to re-establish drainage where the original slab is flat or back-falls.

100mm Upstands

Membrane turned up at least 100 mm onto all adjacent walls — the most common failure point on poorly installed balconies.

24-Hour Flood Test

25 mm water held for 24 hours before any screed or tiling. DFT documented with calibrated gauges and photographic records on every job.

Australian Standard AS 4654.2 — What It Requires

Balcony waterproofing in Australia is governed by AS 4654.2:2012 — Waterproofing membranes for external above-ground use. Minimum requirements include: membrane elongation and recovery to handle Sydney’s thermal movement; minimum dry film thickness of 1.5 mm for exposed external decks; falls to drains of at least 1:100; membrane upstands of at least 100 mm onto adjacent walls; and purpose-made drain and penetration detailing.

Under the NCC, balconies on Class 2 buildings must be waterproofed by a licensed tradesperson. NSW requires a 6-year statutory warranty under the Home Building Act 1989. Econyc provides a 10-year workmanship warranty — exceeding the statutory minimum.

The Balcony Waterproofing Process

Strip existing tiles and screed — finishes removed to expose the concrete substrate.
Concrete preparation — grinding, high-pressure washing, and patching of any spalled or cracked concrete.
Establish falls — minimum 1:100 fall to drain outlets verified. Ardex compound or screed used to re-establish drainage where falls are insufficient.
Prime — manufacturer-specified primer for uniform membrane adhesion to concrete.
Detail coat — reinforcing fabric pressed into the first coat at all junctions: floor-to-wall, corners, drain flanges, and penetrations.
Build coats — multiple coats applied to achieve minimum DFT. Wet film thickness gauges used and DFT photographically documented on every job.
Flood test — deck flooded to 25 mm depth for 24 hours before any screed or tiling proceeds.
Protection layer — separation layer installed over membrane before tiling.

Common Failures — and How We Prevent Them

Inadequate upstand: Membrane must turn up at least 100 mm onto surrounding walls — the most common leak point on badly done balconies. Insufficient DFT: Econyc documents DFT photographically on every job. No flood test: We never skip this step — leaks discovered after tiling cost 5–10× more to rectify.

Sydney Balcony Waterproofing Costs — 2025

Small balcony (up to 10 m²): $1,800–$3,500
Medium balcony (10–30 m²): $3,000–$7,000
Large balcony / terrace (30–60 m²): $6,000–$14,000

Tile removal, structural crack repair, and screed for falls are typically quoted separately. Econyc provides an itemised fixed-price quote after site inspection.

Balcony Leaking or Due for Re-Waterproofing?

Free site inspection · AS 4654.2 compliant · Waterproofing certificate provided