Waterproofing leaks are the silent troublemakers of Sydney homes—just like that one neighbour who mows the lawn at 6am on a Sunday. You don’t notice the damage at first… until suddenly you’ve got swollen skirting boards, tiles lifting like UFOs, and a damp smell that no scented candle on earth can defeat.

If you’ve discovered a bathroom leak—whether in a terrace in Newtown, a semi in Leichhardt, a townhouse in Ryde, or a waterfront apartment in Drummoyne—you’re probably wondering:

“How much does waterproofing repair cost if leaks occur?”

Let’s break it down clearly so you know what to expect, what the issues mean, and how to budget properly for repairs.

Average Cost of Waterproofing Repairs in Sydney

**Typical Range: $800 – $8,000+

(Depending on severity, location, access, and damage)**

Waterproofing repairs can be small and simple—or large, messy, and painfully expensive. The cost varies dramatically based on:

• Whether the leak is surface-level or structural

• Whether tiles need to be removed

• Whether the substrate (floor/walls) is damaged

• Whether plumbing issues are connected

• Apartment vs house leak responsibilities (strata!)

• Age of the home (terrace homes and old brick homes cost more to fix)

Below is a breakdown of typical scenarios and what homeowners in Sydney generally pay.

Common Waterproofing Leak Repair Costs in Sydney

1. Minor Repairs: $800 – $1,800

This usually applies when:

• Only surface silicone or grout has failed

• Shower recess needs resealing

• The waterproofing membrane underneath is still intact

• No tiles need to be removed

This type of repair is common in Concord, Cherrybrook, Castle Hill, and newer apartments across Zetland and Mascot where waterproofing is recent but seals wear out quickly due to heavy use.

Typical jobs include:

• Resealing shower screens

• Regrouting

• Applying epoxy grout

• Reapplying silicone

• Minor crack repairs

These are maintenance repairs—not full waterproofing fixes.

2. Medium Repairs: $2,000 – $4,500

This applies when the waterproofing membrane has begun to fail in isolated areas.

Usually involves:

• Removing a section of tiles (often shower walls or shower floor)

• Installing a new membrane

• Retiling the affected zone

• Matching existing tiles (if still available… good luck with older homes in Petersham or Ashfield!)

This category is the sweet spot for most Sydney homeowners because leaks often start in one specific spot—usually shower corners or niche areas.

3. Major Waterproofing Repairs: $5,000 – $8,000+

This is where things get serious, usually because:

• The membrane under the tiles has failed completely

• Water has soaked into the substrate

• The floor sheeting or screed is damaged

• Mould is present

• Floors or walls have started to deform

Leaks like this are very common in:

• Older homes in Paddington, Balmain, and Marrickville

• Apartments in Homebush, Wolli Creek, and Hurstville with high turnover

• Properties where bathrooms were renovated cheaply (“cash jobs” with no certificate)

This repair usually involves:

• Demolishing the entire shower or entire bathroom floor area

• Rebuilding the floor substrate

• Re-waterproofing completely

• Retiling

• Fixing drainage issues

• Installing a new fall to the floor waste

4. Full Bathroom Tear-Out + Rebuild: $12,000 – $30,000+

When the leak has caused structural damage, the only effective repair is a full bathroom renovation. This happens when:

• The leak has spread into adjacent rooms

• Joists or the subfloor are rotted

• The ceiling below (in two-storey homes) is damaged

• Plumbing needs to be replaced

• Moisture has entered brickwork or internal timber

This is common in:

• Historic terraces in Glebe, Redfern, Paddington

• Split-level homes in Hills District

• Multi-storey homes in St Ives and Turramurra

In these cases, the cost is no longer just “waterproofing repair”—it becomes a multi-trade restoration project.

Why Are Waterproofing Repairs So Expensive?

Waterproofing repairs are costly because leaks never stay politely in one spot. Water travels through:

• Screed

• Timber

• Joists

• Brickwork

• Electrical conduits

• Ceiling voids

This means by the time you see the leak, the damage has often already spread.

Repairs usually involve multiple trades:

• Waterproofers

• Tilers

• Carpenters

• Plumbers

• Painters

• Plasterers

• Electricians

In Sydney, multi-trade jobs get expensive quickly—especially in difficult-to-access homes like narrow terraces, apartments with no lift, or bathrooms packed tightly between bedrooms.

How to Diagnose the Type of Leak You Have

Before budgeting, it helps to understand what kind of leak you’re dealing with.

Shower Floor Leak

Often the membrane under the tiles has failed. Repair cost: $2,000–$6,000.

Wall Leak / Damp Wall Next Door

Waterproofing has failed at a junction or corner. Repair cost: $1,500–$4,000.

Ceiling Leak (From Upstairs Bathroom)

Often severe membrane or plumbing failure. Repair cost: $3,000–$10,000+.

Tile Drummy / Hollow Sounding Tiles

Water has penetrated the screed; tiles have lifted. Repair cost: $2,500–$8,000.

Leak Into Apartment Below

This often becomes a strata claim. Repair cost: $3,000–$15,000+.

In Sydney CBD, Bondi, Parramatta and Chatswood, this is extremely common due to high-rise living.

Strata vs Owner Responsibilities

(For Apartments Across Sydney)

Strata is usually responsible for:

• Structure

• Membrane

• Slab

• External drainage

Owners are responsible for:

• Tiles

• Fixtures

• Internal finishes

So repair costs depend on:

• What failed

• Who owns what

• Building age

• Strata by-laws

In suburbs with older apartment blocks—like Campsie, Hurstville, Bankstown, and Ashfield—strata often gets involved because membranes from the 1970s–1990s frequently fail.

How to Avoid Waterproofing Leaks in the First Place

A little prevention can save tens of thousands of dollars.

1. Always use licensed waterproofers

No certificates = no warranty = huge risks.

2. Don’t tile over old tiles

This traps moisture between layers.

3. Use proper fall to waste

Flat floors = guaranteed puddling and long-term failure.

4. Use premium membrane systems

Cheaper membranes = shorter lifespan.

5. Ensure the bathroom is ventilated

Especially important in tightly sealed suburbs like Waterloo, Zetland, Rhodes, and Macquarie Park.

How MB9 Australia Handles Waterproofing Repairs

At MB9 Australia, we approach waterproofing repairs the same way a surgeon approaches heart surgery—methodically, carefully, and with zero shortcuts.

Our process includes:

• Leak diagnosis with moisture meters

• Full membrane assessment

• Removal of all compromised areas

• Premium waterproofing membrane application

• Rebuilding the substrate if required

• Tiling and finishing

• Warranty-backed waterproofing certification

Whether your home is in Inner West, North Shore, Western Sydney, or Eastern Suburbs, we ensure the repair is done to last—not patched temporarily.

Conclusion: How Much Do Waterproofing Repairs Cost?

In Sydney, waterproofing repairs range widely:

• Minor repairs: $800–$1,800

• Medium repairs: $2,000–$4,500

• Major repairs: $5,000–$8,000+

• Full rebuilds: $12,000–$30,000+

The earlier you catch the leak, the cheaper it is to fix. If your bathroom is showing signs of water issues, get it investigated early.

If you’re planning bathroom, kitchen or home renovation work in Sydney—and want professional help diagnosing or repairing waterproofing issues—visit www.mb9.com.au to find out more about renovation services from MB9 Australia Pty Ltd.