Why getting balcony leak repair done right matters

A couple of winters ago, I noticed damp spots forming under our living room ceiling — just beneath the upstairs balcony. The signs were subtle at first, but within weeks, bubbling paint and that unmistakable musty smell confirmed it: water was getting in. A rushed DIY patch job from a few years earlier had finally failed.

It didn’t just cost us in repairs — it cost us weeks of disruption and thousands in hidden damage. That’s when I realised: balcony leak repair isn’t just another odd job. It’s a specialist task that demands experience, compliance, and the right materials from the start.

Whether you’re fixing an old leak or waterproofing a new build, choosing the right contractor can make or break the long-term integrity of your home. Here’s how to get it right the first time.

Understand the scope: what’s actually involved?

Balcony waterproofing might sound straightforward, but it’s more complex than sealing a crack or slapping on a membrane. A good contractor will:

  • Inspect the substrate (concrete, timber, tiles)
  • Identify previous water pathways and failures
  • Remove existing coatings where needed
  • Apply correct primers, sealants, membranes, and drainage
  • Ensure surface fall for proper runoff
  • Test the system before the handover

A reputable pro will also discuss:

  • Moisture detection tools
  • Council or strata requirements
  • Long-term durability of different systems

If your contractor’s quote skips these steps, dig deeper.

Check for balcony safety compliance

In New South Wales, balcony safety isn’t just about construction — it’s a legal and rental compliance issue. Contractors working on high-risk areas like decks or balconies must ensure their work meets relevant safety expectations.

As outlined in the NSW Government’s balcony safety compliance guide, waterproofing failures can compromise structural integrity, especially in rental properties or strata buildings. A qualified contractor must understand and meet these standards, from surface slope to drainage and sealing around railings.

Ask your contractor how their method aligns with these compliance expectations. If they don’t know — that’s a problem.

Ask the right questions (and listen to the answers)

Don’t just ask how much — ask how. Some key questions to include:

  • What’s your process for identifying root causes of leaks?
  • Do you remove old membranes or work over them?
  • What waterproofing system do you recommend and why?
  • Can you show me before-and-after projects?
  • Do you offer a written guarantee? For how long?

Good contractors will answer clearly. Dodgy ones will dance around details or promise “quick fixes.”

One time, I asked a tradie about membrane thickness. He replied, “We do what’s needed, mate.” That vague answer was all I needed to decline the job.

Simulated experience: how a small decision avoided a big repair

Last year, a client of mine in Parramatta hired a waterproofing team without doing proper checks. The crew used a roll-on membrane that looked great at first, but they skipped priming, and within six months, water had seeped through expansion joints.

They ended up hiring us to rip everything up and re-do it from scratch, at triple the original cost. That’s why a few extra questions upfront are worth every second. Because of fixing waterproofing after failure? That’s when things get expensive.

Red flags to watch out for

Hiring a waterproofing contractor doesn’t need to be a minefield — but it pays to know what not to accept.

🚩 No licence or unclear credentials

If they can’t show you a licence number, stop there.

🚩 Cash-only or verbal quotes

You need a paper trail for warranty and compliance.

🚩 One-size-fits-all solutions

Your balcony’s design, slope, and materials all matter.

🚩 No mention of membrane type

If they can’t explain the difference between acrylic, sheet, or bitumen-based systems, they’re not ready.

What’s in a quote? More than just cost

An accurate quote should include:

  • Surface preparation
  • Removal of existing membranes or finishes
  • Primer, waterproofing system, topcoat (if needed)
  • Labour and equipment
  • Waterproofing certification
  • Site protection and cleanup
  • Warranty duration and coverage

Make sure it also includes:

  • Total square metres of area covered
  • Any areas that won’t be waterproofed
  • Timeline with weather contingencies

If you're comparing quotes and need guidance, check out this article on what to check before hiring a waterproofing contractor.

Licences, insurances, and guarantees

Here’s what to look for beyond skills:

No licence? No deal.

Waterproofing materials: what your contractor should use

Materials aren’t all equal. You’ll want someone who can walk you through:

  • The brand and type of membrane
  • Compatibility with tile adhesives, if tiling over
  • UV resistance for exposed areas
  • Crack-bridging capability (especially on old concrete)

Don’t be shy — ask for technical data sheets. Any serious contractor will have them handy.

Project timelines and weather planning

Balcony waterproofing jobs don’t happen overnight. Expect:

  • 1–2 days for prep and removal
  • 1–3 days for membrane application (with drying time)
  • 1–2 days curing or topcoat (if tiled or coated)

Weather can delay things, especially with water-based systems. Your contractor should factor this in.

Think long-term: balcony resale and strata value

Waterproofing is one of those jobs where quality shows — or fails — over time. If you live in a strata complex:

  • Ask if the contractor works with strata managers
  • Ensure their certification and method meet insurance expectations
  • Keep waterproofing records for future resale

You’d be surprised how many property deals hit delays because of missing documentation or past leak issues.

To see how cutting corners can cost thousands, check this breakdown of balcony waterproofing failures and how to avoid them.

Final thoughts

Hiring a balcony waterproofing contractor shouldn’t feel like a gamble. The key is to treat it like what it is: a specialised trade that protects your home’s integrity and value.

If your contractor can’t explain their process, product, or paperwork, move on.

But when you find someone who understands the full scope of balcony leak repair, explains your options clearly, and follows NSW waterproofing regulations, you’re protecting your home for years to come.