Waterproofing in Strata Buildings: Who Is Responsible?

When a balcony leaks into the apartment below in a strata building, who pays? Understanding the boundaries between lot owner and owners corporation responsibilities.

One of the most contentious issues in Melbourne apartment buildings is responsibility for waterproofing repairs. When water from a balcony or bathroom leaks into another lot, the question of who pays — the lot owner or the owners corporation — can become heated quickly. Understanding the legal framework helps navigate these situations.

The General Principle

Under the Owners Corporations Act 2006 (Victoria), the owners corporation is responsible for the repair and maintenance of "common property." Individual lot owners are responsible for maintaining their own lot.

The complication is that waterproofing membranes often sit at the boundary between common property and lot property, and different buildings define these boundaries differently in their plans of subdivision.

Typical Scenarios

Balcony Waterproofing

In most strata schemes, the structural slab of a balcony is common property, but the surface finishes (tiles, membrane) may be lot property. This creates a grey area:

• •If the membrane has failed due to age and wear, many VCAT decisions have held this is an owners corporation responsibility because the membrane protects common property (the structural slab)
• •If the membrane was damaged by the lot owner's renovations or modifications, responsibility typically falls on the lot owner

Bathroom Leaks Affecting Lower Lots

When a bathroom in one apartment leaks into the apartment below:

• •The waterproofing membrane in a bathroom is generally lot owner property
• •However, if the original waterproofing was defective (a building defect), the owners corporation or the original builder may bear responsibility
• •If the leak is due to maintenance failure by the lot owner, they are typically responsible

Common Area Leaks

Leaks in common areas — car parks, lobbies, roof terraces, communal gardens — are clearly the owners corporation's responsibility.

What to Do When a Leak Occurs

1. Document Everything

• •Photograph the damage
• •Note when you first observed the issue
• •Record weather conditions if relevant
• •Keep records of any communication with neighbours and the owners corporation

2. Notify the Owners Corporation

Even if you believe the issue is within your lot, notify the owners corporation (or strata manager) in writing. This creates a paper trail and gives the OC the opportunity to assess whether common property is affected.

3. Get a Professional Assessment

Before arguments about responsibility consume everyone's energy, get an independent professional assessment. A qualified waterproofing specialist can usually determine:

• •Where the leak is originating
• •Whether the membrane has failed
• •Whether the failure is due to age, defect, or damage
• •What repairs are needed

This assessment becomes an objective basis for determining responsibility.

4. Understand Your Options

If responsibility is disputed, options include:

• •Negotiation between the lot owner and owners corporation
• •Mediation through Consumer Affairs Victoria (free)
• •Application to VCAT for a determination

Practical Advice

In our experience working with strata buildings across Melbourne, the most productive approach is:

1. Focus on fixing the problem first. Water damage gets worse every day it's left. Arguing about who pays while water continues to cause damage benefits nobody.

1. Get a clear, detailed quote. This helps both parties understand the actual cost and often makes agreement easier.

1. Consider the maintenance fund. Many owners corporations have (or should have) a maintenance fund with provisions for waterproofing repairs.

1. Check for building defects. Recently completed buildings may still be within Domestic Building Insurance warranty periods (6 years for structural defects, 2 years for non-structural from completion).

We work with strata managers and owners corporations regularly and can provide the kind of clear, objective assessments that help resolve these situations efficiently. Our reports document the source, cause, and recommended repair — giving all parties the information they need to move forward.