5 Signs Your Shower Waterproofing Has Failed

When homeowners contact us for a leaking shower repair, the first question is almost always the same:
Can this be fixed by sealing the grout, or do the tiles need to come up?

The answer comes down to one critical factor: shower waterproofing.

If the waterproofing membrane underneath your tiles is still intact, sealing grout joints (especially with epoxy) can help stop water from entering the tile bed and extend the life of your shower.

But once waterproofing has failed, sealing the surface won’t solve the issue. Water will continue travelling beneath the tiles, and the only proper fix is to remove the affected tiles and rebuild the system correctly.

After decades of repairing leaking showers, we’ve found one consistent truth:
The condition of the waterproofing determines the repair method.

If you’re unsure how waterproofing works, you can read more here:
👉 https://allspextiling.com.au/what-is-shower-waterproofing/

This is the most obvious and serious warning sign.

You might notice:

• Water running onto the bathroom floor
• Damp carpet or flooring outside the shower
• Swollen or lifting skirting boards
• Moisture in nearby walls
• Bubbling paint or stains on ceilings below
• Water dripping through lights or ceilings

If water is leaving the shower area, the shower waterproofing system has already failed, or was never installed properly.

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The drain is one of the most common failure points.

Constant water exposure and movement can cause issues if the membrane wasn’t properly installed around the waste pipe.

Signs include:

• Cracked tiles
• Broken or deteriorating grout
• Movement around the drain

Many homeowners try resealing or patching, but if water is already underneath, these fixes won’t last.

👉 Related: https://allspextiling.com.au/shower-sealing-vs-removing-tiles/

A properly built shower should feel solid.

Warning signs include:

• Spongy or soft flooring
• Hollow (drummy) sounds when tapping tiles

This usually means water has reached the substrate and weakened the bond. In some cases, it can even become a safety issue.

👉 Avoid costly mistakes: https://allspextiling.com.au/diy-tile-repair-mistakes/

Using moisture testing and thermal imaging, we often find water spreading beyond where it should be.

If moisture appears:

• In adjacent walls
• Outside the shower base
• Beyond the waterproofed zone

…it’s a strong sign the shower waterproofing membrane is compromised.

This is extremely common.

The shower has been:

• Regrouted
• Resealed
• Patched multiple times

…but the problem keeps returning.

That’s because the issue isn’t the surface; it’s underneath.

Learn more: https://allspextiling.com.au/3-ways-fix-leaking-shower-tiles/

In older homes, especially those built before modern standards, some showers don’t have waterproofing membranes at all.

Instead, they relied on tiles and grout alone, which are not waterproof.

Once water gets through, there’s nothing stopping it from spreading into surrounding structures.

For reference, Australian standards now require proper waterproofing in wet areas:
👉 https://ncc.abcb.gov.au/
👉 https://www.qbcc.qld.gov.au/

We were once called to inspect a leaking shower that had already been “fixed” twice.

• First repair: cement regrouting
• Second repair: epoxy sealing

Both failed within months.

When we removed the first tile, water literally ran out from underneath.

The issue?
The waterproofing membrane had never been properly installed around the drain.

The only real solution was:

• Remove tiles
• Rebuild the screed with proper fall
• Install new waterproofing
• Retile the base

👉 See full process: https://allspextiling.com.au/how-to-fix-a-leaking-shower-step-by-step-guide/

Sealing can work only if the waterproofing is still intact.

It acts as a preventative measure, helping stop further water entry.

But if waterproofing has already failed, sealing is just a temporary fix.

👉 More detail: https://allspextiling.com.au/why-epoxy-grout-is-the-smart-choice-for-showers-and-balconies/

If you’re noticing any of these signs, it’s best to act early.

Left untreated, a leaking shower can lead to:

• Structural damage
• Rotting timber
• Mould growth
• Expensive repairs

At Allspex Tiling, we focus on identifying the true cause of the issue so the repair actually lasts, not just temporarily covering it up.

If you’re dealing with a persistent leak or unsure whether your shower waterproofing has failed, you can learn more about our professional shower repair approach.

👉 Start here: https://allspextiling.com.au/do-i-really-need-to-rip-up-my-shower/
👉 Or view costs: https://allspextiling.com.au/shower-repair-cost-guide/

Signs include water escaping the shower, damage to surrounding areas, and moisture spreading beyond the shower base.

Yes, but only if the waterproofing is still intact. Otherwise, tile removal is required.

Not always. They indicate water has entered the tile bed, but further inspection is needed.

Poor installation, structural movement, incorrect falls, and aging materials.

Only when used as prevention. If waterproofing has failed, sealing is temporary.