Leaking balcony: water damage below, and who pays

A leaking balcony belongs to two places at once: the balcony where water gets in, and the room underneath where the damage shows. Who pays turns on who owns the waterproofing.

Read from primary sources · Editor-reviewed · Current as at 20 September 2026

By the waterdamagequotesau.com editorial team · Published 20 September 2026 · Last reviewed 20 September 2026 · 8 min read

10 primary sources cited on this page. How we check what is on this site

A leaking balcony is a problem that belongs to two places at once: the balcony, where the water gets in, and the room underneath, where the damage shows. In an apartment those are often two different lots, and the balcony itself may belong to neither of them. Who pays turns on who owns the waterproofing, and the building code is specific about what that waterproofing has to be.

Who repairs what, in a NSW strata scheme

Balcony responsibility under the NSW Government’s common property memorandum and strata guidance. Check your own plan and by-laws. Read 4 October 2026.
Part of the balcony	Usually
Original tiles and associated waterproofing	Owners corporation
Balcony doors, walls, columns, railings, ceilings	Owners corporation
Tiles and waterproofing an owner added after registration	Lot owner
Decks, planter walls and structures within the balcony not shown as common property	Lot owner
Water damage coming from common property into a lot	Owners corporation

NSW Government, Common property memorandum · March 2022, read 4 October 2026

Listed under balconies and courtyards as the owners corporation’s, with balcony doors, walls, columns, railings and ceilings. The lot owner is listed for decks, planter walls and other structures within the balcony not shown as common property, and for floor tiles and associated waterproofing an owner added after registration. Check your scheme’s plan and by-laws.

So for an original balcony the memorandum points to the owners corporation, both for the membrane and for water damage coming from it. Where the owners corporation does not repair common property, s 106(5) of the Strata Schemes Management Act lets a lot owner recover reasonably foreseeable loss (Strata Schemes Management Act 2015 (NSW) s 106(1)). The exception is a balcony an owner has retiled or rebuilt: that work, and its waterproofing, can be the owner’s.

What the building code requires

NCC 2022, Volume Two, H2D8 (External waterproofing) · NCC 2022, read 4 October 2026

For houses: their external waterproofing must use membranes complying with AS 4654.1, designed and installed in accordance with AS 4654.2. It does not apply to a concrete slab with a step-down of at least 50 mm below the internal floor and no habitable space beneath, or to spaced decking. For apartments, Volume One F1D5 requires a waterproofing membrane to AS 4654.1 and AS 4654.2 on a roof, balcony, podium or similar horizontal surface, and F1D4 requires exposed joints to be protected and not run beneath a planter box.

The exceptions matter. A concrete slab stepped down at least 50 mm below the internal floor with no habitable space beneath, and spaced timber decking, are outside the requirement for houses. A tiled balcony over a living space is the case the requirement is written for, where the membrane, its turn-up at the walls and the door sill are doing all the work. AS 4654.2 is a paid Australian Standard and its text is not reproduced here.

Get the room below dried

Four digits, and restoration companies advertising for your postcode call you back. The balcony repair and the drying are separate jobs.

The door sill is the usual weak point

Queensland Building and Construction Commission, Technical Feature: Waterproofing requirements for doorways to decks and balconies (13 February 2017) · 13 February 2017, copy hosted by a third party, read 4 October 2026

Contributing to leakage below door and window sills that open onto a deck or balcony. The QBCC says water leakage below door openings had been a concern for it and other state regulators for a number of years, and that high wind pressure can push rain under a sill into the building or the wall cavity.

That is consistent with water showing inside on the floor just past the door, or in the ceiling of the unit below near the external wall, rather than in the middle of the room. It is also why the evidence matters: whether water appears after wind-driven rain, after the balcony is hosed, or all the time points to the sill, the membrane or a pipe.

The builder’s warranty

In a recent building, the defect route may pay for the part insurance argues about. In New South Wales waterproofing is a major element of a building, and a major defect carries a 6-year statutory warranty from completion (Home Building Act 1989 (NSW) s 18E(4)). In Queensland, work that allows water penetration into a building is structural defective work (Queensland Building and Construction Commission, What is defective work). Water ingress sets out the three states side by side, and leaking showers covers the same warranty for wet areas.

Insurance and the room below

The failed membrane is where the exclusion for wear and tear, rust or corrosion applies (Insurance Contracts Regulations 2017 (Cth) reg 19(2)(b)). The damage it causes below is the part a policy may cover, subject to its wording on gradual leaks; in strata, that is the owners corporation’s building policy for the building and your contents policy for your things. Whoever pays, the ceiling and wall below have to be dried before they are repaired: on the published rate card, two rooms over five days is $2,269 excluding GST. Ceiling water damage covers when a wet ceiling can stay and when it comes down.

Common questions

Why is my balcony leaking into the room below?

Common points are the waterproofing membrane under the tiles, its junction with the wall or the door sill, and the drainage outlet. The QBCC has said wind-driven rain is one of the main factors in leakage below door and window sills that open onto a deck or balcony.

What does the building code require for balcony waterproofing?

For houses, NCC 2022 H2D8 requires balconies and terraces above internal spaces to use membranes complying with AS 4654.1, designed and installed to AS 4654.2, with exceptions such as spaced decking. For apartments, F1D5 requires a waterproofing membrane to the same standards on a balcony or podium.

Who pays for a leaking balcony in a NSW strata building?

The NSW Government lists balconies and balcony doors among the owners corporation's repairs, and the common property memorandum lists the original tiles and associated waterproofing as common property. Tiles and waterproofing an owner added later are the owner's.

Is a leaking balcony a building defect?

In New South Wales waterproofing is a major element of a building, and a major defect carries a 6-year statutory warranty. In Queensland, work that allows water penetration into a building is structural defective work.

Does insurance cover a leaking balcony?

The failed membrane is generally where the wear and tear exclusion applies. Damage inside caused by a storm may be a storm claim; damage from a slow leak through a membrane is the gradual case. In strata, the owners corporation's policy is the one for the building.

What does it cost to dry the room below a leaking balcony?

On the published rate card, two rooms over five days is $2,269 excluding GST. The balcony waterproofing repair is separate.

Sources cited on this page

Every figure above was read from the source it is attributed to on 20 September 2026. How we check this.