Cost to Repair a Leaking Balcony in Sydney

If you have discovered a leak in your balcony, you are definitely not alone. Balcony leaks have become one of the most common issues Sydney homeowners face, especially in apartments, townhouses and older homes across the North Shore, Inner West, Hills District and coastal suburbs. Many owners only notice the problem once water starts showing inside the home or stains appear underneath the slab.

The question every homeowner asks is simple: how much does it cost to repair a leaking balcony in Sydney?

There is no single price that fits every balcony, but most professional repairs in Sydney fall between 2,500 and 12,000 dollars, depending on the size of the balcony, the level of water damage, and whether the waterproofing has completely failed.

Some projects are straightforward. Others require stripping the entire balcony, removing tiles, installing new drainage, rebuilding the substrate and applying a new membrane. In severe cases, the cost can range from 15,000 to 35,000 dollars, especially when structural or remedial building work is required.

This guide will walk you through all the realistic costs, the common causes of balcony leaks, why they happen so often in Sydney, and how to prevent the leak from becoming a much bigger problem down the line.

Sydney’s climate plays a big part. Heavy storms, summer heat, and coastal humidity all put pressure on balcony membranes and drainage systems. But the more common reason is this: many balconies were not waterproofed correctly when they were first built.

A lot of homes built between the early 2000s and mid-2010s used cheaper waterproofing products and rushed installation methods. Over time, these membranes crack, lift, or deteriorate. Once that happens, water begins to seep beneath the tiles and into the slab.

Other common causes include:

• Poor drainage or a blocked drain
• Cracks in the screed or concrete slab
• An incorrect balcony fall is causing water to pool
• Loose tiles due to movement
• Failed grout or silicone joints
• Age and natural wear

Once water gets underneath the membrane, it does not dry out. Instead, it spreads. This is why the longer a balcony leak is left untreated, the more expensive the repair becomes.

Let’s break it down clearly by showing typical cost brackets. Below is a coloured graph to give you a quick visual guide.

Most Sydney balcony repairs fall into one of these groups:

1. Minor leak repair

Approx. 1,500 to 3,500 dollars

This usually applies to very small balconies where the issue is restricted to surface waterproofing, grout replacement or edge sealing.

2. Mid-level waterproofing repair

Approx. 3,500 to 7,500 dollars

The tiles are removed, the membrane is replaced, and the drainage may be adjusted. This is the most common category for Sydney homes.

3. Full balcony rebuild

Approx. 8,000 to 18,000 dollars

This includes tile removal, screed repair, new membrane, new tiles, and new drainage. Many apartments built 10 to 20 years ago fall into this category.

4. Remedial or structural balcony repair

Approx. 20,000 to 40,000 dollars

This applies when the balcony has underlying structural movement, cracked slabs, rotten substrate or severe water penetration into the home. If the project requires a remedial builder, site engineering, or major reconstruction, the price increases.

If your balcony leak is linked to structural movement or moisture ingress into internal walls, you can learn more about when remedial work is required on the Remedial Building Services page.

There are a few key factors that influence the price more than others:

The condition of the existing membrane

If the membrane is peeling, cracked or completely failed, the balcony will need a full strip and new waterproofing.

Tile type and layout

Porcelain tiles and larger formats can cost more to remove and reinstall.

Balcony size

A 10 square metre balcony will obviously cost more than a small 3 square metre one.

Drainage issues

If the balcony has an incorrect fall or poor drainage design, it may require complete remediation.

Access and height

Apartments that require lift access, material transport or protective measures often cost more.

Remedial work hidden underneath

If water has travelled into the home, the repair becomes more involved.

This is why quotes vary so much between properties. No two balconies leak in the exact same way.

Here are a few signs that almost always indicate the membrane has failed:

• Water stains are appearing on the ceiling below
• Paint bubbling or peeling near the balcony doors
• Damp smells inside the room adjoining the balcony
• Tiles that sound hollow when tapped
• Loose grout or hairline cracks across the surface
• Ponding water that does not drain properly

If you see any of these early red flags, it is worth having the balcony inspected properly. A leaking balcony never fixes itself, and ignoring it usually leads to a far more expensive repair later.

If moisture has spread inside the home, you can read more about internal water damage and repair options on the Insurance Building Repairs page.

A proper balcony repair is done in stages. While each home is different, the general process looks like this:

First the tiles are lifted to expose the screed. If the screed is damaged, it is replaced. From here, the slab is checked for cracks or moisture. Once it is dry and stable, a new waterproofing membrane is applied. This may involve two or three layers to meet current standards. The balcony is then retiled, drainage is corrected, and all joints are sealed with proper flexible sealants.

The key difference between a cosmetic repair and a long lasting repair is the membrane system. A good membrane is the barrier that prevents future leaks. It must be done by a licensed professional who understands NSW waterproofing requirements.

Many balconies in Sydney apartment blocks were originally built with incorrect falls or insufficient drainage. Over time, tiny amounts of water begin to accumulate under the tiles. Anyone living in high rise areas like Homebush, Parramatta, Chatswood or Mascot sees this frequently.

Strata buildings, in particular, often require specialised remedial work because balconies may share membranes or sit directly over other apartments. If the leak impacts common property, the strata committee may need a remedial builder instead of a standard waterproofing contractor.

You can learn more about building defects and strata repairs on the Strata and Remedial page.

A lot of homeowners try quick fixes at first. Resealing grout, applying a liquid waterproofing paint or replacing a small section of tiles may offer temporary relief, but if the membrane underneath is already compromised, these surface fixes will not stop the leak for long.

A proper repair should last many years. A quick patch usually lasts a few months. This is why repairing the balcony correctly the first time is not just the better option, but the cheaper long term option.

This depends on the cause of the leak.

Most insurers do not cover damage caused by gradual deterioration or poor workmanship. However, they may cover the internal damage caused by the leak, such as swollen skirting boards, damaged ceilings or wall repairs. The balcony repair itself is normally at the owner’s expense unless a construction defect can be proven.

If your home has internal water damage from a balcony leak, Ardent can assist with the repair process. You can read more about these services on the Insurance Building Repairs page.

A small repair may take three to five days. A full balcony rebuild may take ten to fourteen days, depending on weather, tile selection and drying times for the membrane layers.

Yes. Sydney’s moisture and rain patterns have increased again in recent years. Leaks worsen during winter and storm season. Repairing a balcony early saves thousands because it prevents the water from spreading into internal walls, flooring, and ceilings.

Balcony failures can also impact property value. Buyers look closely at water damage, and strata buildings in particular can lose confidence quickly when leaks are visible.

A leaking balcony is not something you want to ignore. Even a small amount of moisture can spread underneath tiles, into the slab, and eventually into the inside of your home. The earlier you repair it, the cheaper and easier it is.

Understanding the cost ranges helps you plan realistically. Whether your balcony needs a minor patch, a new membrane or full remedial reconstruction, a qualified team will guide you through the process and ensure the leak does not return.

If your balcony is showing signs of water damage, Ardent Construction can help. Our team specialises in balcony repairs, waterproofing, remedial building, and full restoration projects across Sydney. Get in touch, and we will walk you through the best approach for your home.