How to Fix a Leaking Balcony (Without Removing Tiles)

Thu, 26 Mar 2026 05:41:44 GMT

The Problem

Leaking balconies are one of the most common issues in both residential and commercial buildings. Water penetrates through grout lines, cracks, or failed membranes — leading to damage below, mould, and costly repairs.

Traditionally, fixing this meant ripping up tiles and starting again … but not anymore.

THE SOLUTION: Over-Tile Waterproofing

Using ACTFLEX 400 Clear, you can seal leaks directly over existing tiles, saving time, labour, and cost!

What You’ll Need:

•ACTFLEX 400 Clear

•Roller or brush (mohair roller recommended)

•Cleaning solution (sugar soap or degreaser)

•Crack repair / sealant (e.g. MS polymer like ACTFLEX MS PRO)

•Optional: Anti-slip additive (for outdoor areas)

Step-by-Step Guide:

1. Clean the surface thoroughly

Remove dirt, grease, mould, and loose material

Pressure clean if needed

Treat mould with diluted bleach solution

Allow surface to dry completely

**This step is critical — poor prep = poor results

2. Repair Cracks & Grout Lines

Replace or repair missing grout

Fill cracks with a flexible sealant

Ensure surface is solid and watertight before coating

3. Apply ACTFLEX 400 Clear

Mix 2:1 (product to water) for roller application

Apply first coat evenly across entire area

Focus on grout lines and joins

4. Apply Additional Coats

Apply 2–3 coats total

Allow minimum 4 hours between coats

Optional: Broadcast anti-slip into first coat

5. Allow to Cure

Keep surface dry for 3–5 days

Avoid rain or water exposure during this time

The Result:

Fully sealed tiled surface

Transparent finish (tiles still visible)

Flexible, UV-resistant membrane

Up to 5 years protection

⚠️When This Method Isn’t Suitable⚠️

This system is ideal for remedial waterproofing, but NOT if:

The substrate is structurally unsound

There is major movement or failure underneath

A full compliant system is required (new builds)

--In those cases, a full system using ACTFLEX 906 WPU is recommended.

wollongong-waterproofing

How to Fix a Leaking Balcony (Without Removing Tiles)

The Problem

Traditionally, fixing this meant ripping up tiles and starting again … but not anymore.

THE SOLUTION: Over-Tile Waterproofing