Internal Wet Area Waterproofing System (AS3740, AS4858 & ISO 13007 Compliant)

Real World Site Tested System – Primer to Tile, No Compatibility Failure

Internal wet area waterproofing is one of the highest failure points in construction. Most issues do not come from a single product failing—they come from incompatible systems being combined. When primers, membranes, screeds, and adhesives are not designed to work together, the system breaks down at the interfaces.

This is why a complete, compliant waterproofing system is critical.

The ACTFLEX internal wet area system has been developed as a full-chain solution, designed to meet:

• AS 3740:2021 – Waterproofing of domestic wet areas
• AS 4858:2004 – Waterproofing membranes
• ISO 13007 – Tile adhesives

This system is not theoretical. It has been applied and tested under real job site conditions, from substrate preparation through to final tiling.

Why Bathroom Waterproofing Compliance Is Critical

Waterproofing in bathrooms is continuously exposed to:

• Direct water exposure
• Vapour pressure from hot showers
• Movement between wall and floor junctions
• Structural shrinkage and expansion

If the system is not compliant or compatible, water will not stay contained within the wet area. Instead, it migrates behind tiles, into screeds, and into surrounding substrates.

This leads to:

• Tile adhesive failure
• Screed debonding
• Membrane breakdown
• Mould growth and structural damage

Compliance with AS3740, AS4858, and ISO13007 ensures that each layer has been tested for performance under real conditions, including movement, moisture, and load.

The Importance of System Compatibility

A wet area system is not a single product. It is a layered structure, and every layer depends on the one below it.

The system consists of:

• Primer
• Joint treatment / bond breaker
• Waterproofing membrane
• Screed
• Tile adhesive
• Tiles

Each of these layers must:

• Chemically bond to the next
• Maintain flexibility under movement
• Resist moisture without degrading

If one layer is incompatible:

• The bond line becomes the failure point
• Movement stress concentrates at weak interfaces
• Water tracks between layers instead of being stopped

This is why mixing different brands or untested combinations leads to failure—even if each product individually meets a standard.

---

ACTFLEX Internal Wet Area System (Complete Build-Up)

Substrate Preparation and Priming

The system begins with controlling the substrate.

• ACTFLEX 200 Primer is used for standard substrates to seal porosity and create a consistent bonding surface.
• Where moisture exceeds 5%, ACTFLEX EP 250 is used as a moisture barrier. This prevents vapour pressure from pushing through and breaking the system above.

This step is critical. If moisture is not controlled at substrate level, it will compromise every layer above.

Joint Treatment and Movement Control

Movement occurs at:

• Wall-to-floor junctions
• Internal corners
• Penetrations

These areas must be treated with:

• ACTFLEX MS PRO (fillet joints)
• or ACTFLEX SA Tape / Flex Tape / Super Flex Tape / Mesh Tape

These products act as bond breakers and reinforcement zones, allowing movement without transferring stress into the membrane.

Without this step, membranes split at junctions—this is one of the most common failure points on site.

---

Waterproofing Membrane Layer

The primary waterproof barrier is applied using:

• ACTFLEX 989 CWP (cementitious system)
  or
• ACTFLEX 906 WPU (ready-to-use polyurethane system)

Both systems are compliant with AS4858 and designed to:

• Bridge cracks
• Remain flexible under movement
• Resist continuous water exposure

The membrane must fully bond to the primer and integrate with the joint system. If adhesion fails here, the entire waterproofing system is compromised.

Engineered Screed Installation

Once the membrane is cured, the next layer is:

• ACTFLEX SCREED X

This is not a standard screed. It is an engineered system designed to:

• Form falls to waste
• Maintain bond integrity
• Distribute load without stressing the membrane

If screed is not compatible:

• It can debond from the membrane
• Create hollow sections
• Allow water to travel beneath the surface

---

Tile Adhesive System (ISO 13007)

Tiles are fixed using:

• ACTFLEX BIOSET C2TES1

This adhesive meets ISO 13007 classification:

• High bond strength (C2)
• Non-slip (T)
• Extended open time (E)
• Deformability (S1)

This is critical because the adhesive must:

• Bond to the screed
• Absorb movement from below
• Hold tiles under wet conditions

Rigid or incompatible adhesives are a major cause of tile failure in wet areas.

Real World Site Testing

This system has been applied and tested on live job sites, not just in controlled environments.

Testing includes:

• Full installation sequence (primer to tile)
• Exposure to wet area conditions
• Movement across junctions
• Adhesion between all layers

This confirms that the system performs as a complete structure, not just as individual products.

Why Waterproofing Systems Fail

Most failures are not product defects—they are system failures.

Common causes include:

• Mixing incompatible brands
• Incorrect primer selection
• No bond breaker at junctions
• Using rigid adhesives over flexible membranes
• Moisture not controlled at substrate level

When this happens:

• Membranes lift or crack
• Screeds debond
• Tiles become loose
• Water penetrates behind the system

The Result of Using a Complete System

Using a fully compatible ACTFLEX system delivers:

• Verified compliance with AS3740, AS4858, and ISO13007
• Controlled moisture behaviour from substrate to surface
• Consistent adhesion between all layers
• Long-term durability under real conditions

This is not just waterproofing. It is a fully engineered wet area system designed to eliminate failure points.

Internal Waterproofing System – Final Position

If the system is built correctly:

• Water is contained at the membrane layer
• Movement is absorbed at junctions
• Load is distributed through the screed
• Tiles remain bonded long term

If the system is not compatible:

• Failure occurs at the weakest interface
• Water bypasses the system
• Repairs become invasive and costly