Hidden Shower Leaks Causing Water-Damaged Plaster in Melbourne Homes

Across many Melbourne suburbs, homeowners are discovering bubbling paint, swollen skirting boards and water-damaged plaster near their showers — and these symptoms often point to a much bigger problem hiding behind the tiles. Our team rebuilds showers across Melbourne every week, and we continue to find the same critical waterproofing failures causing damage that homeowners cannot see from the outside.

One recent example involved a Porter Davis–built home, where the shower looked fine at first glance. Once opened, however, we uncovered significant hidden damage — the same types of issues we see in many Melbourne homes, regardless of builder or suburb.

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What We Are Finding in Showers Across Melbourne.

During shower rebuilds and inspections, the same defects keep appearing:

• Missing or incorrectly installed puddle flanges
• Water escaping behind the wall and into the plaster
• Bubbling paint and soft plaster around the bathroom
• Timber framing and subfloors beginning to rot
• Mould forming behind the tiles and linings
• Waterproofing that doesn’t meet NCC or AS 3740 standards

These issues remain completely invisible until the shower is opened or until the plaster shows signs of moisture — usually long after the leak has started.

If you’re noticing bubbling plaster, cracked paint, water stains or swollen skirting boards near your shower, these are common early signs of a hidden waterproofing failure.

What the Surface Hides

Before

The shower looks normal. No obvious leaks. No visible cracks.
The only sign might be minor bubbling paint or soft plaster near the shower.

After

Once the shower is opened, the real issues become clear:

• Rotting timber in the wall cavity
• Waterlogged plasterboard
• Mould hidden behind tiles
• Failed or incomplete waterproofing
• No puddle flange installed at the waste

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This type of hidden damage is now being found in Melbourne suburbs right across the city — not just in older homes and not limited to any particular builder.

Case Study: Berwick Leaking Shower (Porter Davis Build)

A recent project involved a Porter Davis home that appeared perfectly fine externally. But once opened, we found:

• No puddle flange installed
• Water tracking into the wall cavity
• Plaster swelling and softening outside shower screen on wall linings near the shower base
• Mould beginning to form behind the plasterboard wall linings
• Rotting structural framing

Only a full shower rebuild restored the bathroom to current NCC and AS 3740 standards and prevented the damage from spreading further.

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Why Water-Damaged Plaster Near a Shower Is a Major Warning Sign

Water-damaged plaster is almost never the real problem — it’s a symptom of what is happening behind the wall.
If left untreated, hidden leaks can cause:

• Structural timber rot
• Widespread mould growth
• Damage to adjoining rooms
• Expensive long-term repairs
• Waterproofing compliance issues
• Insurance complications

The earlier the issue is assessed, the more of your home can be protected.

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Protect Your Home Before More Damage Appears

If you’re seeing bubbling plaster, peeling paint, damp smells, or soft walls near your shower, it may already be leaking behind the tiles. A proper inspection is the safest way to diagnose the cause and prevent further damage within your home.

Important Lesson: Don't Re-grout a leaking Shower

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