Elongation of Waterproofing Membranes


Waterproofing membranes are sold based on the merits of the elongation properties and their ability to bridge cracks.
The current Australian Standards classify membranes into Class I, II and III according to % Elongation:

Class I: 0-59%
Class II: 60-299%
Class III: 300% and above

Note: The % E is measured without any re-enforcing mat – which when added, will reduce the elongation.


The membrane can have restricted or non-restricted movement depending on its bonding to the substrate. The way the membrane is bonded also affects the extent of the flexibility and elasticity of the product.

If you use a bond breaker over a crack, it is much better if the crack were to open up later on. This is shown in Figure 1 (bond breaker) in comparison with Figure 2 (no bond breaker).

The stress on the membrane in Figure 2 is much more severe and likely to lead to failure. Even a small opening of the crack in the underlying concrete substrate will require extensive elongation.


Cracks formed after the application of the membrane have no membrane distance so they are like Figure 2. When this occurs, the membrane will extend but the result will be serious necking of the membrane across the newly formed gap and may lead to the membrane tearing when subject to small movements.
It is important to note that the membrane can only stretch to a limited length before its waterproofing properties fail, regardless of its elongation capability.


The elongation properties of a waterproofing membrane are best preserved in situations where the membrane is not directly bonded over the crack due to a bond breaker being in place.

When cracking occurs after a membrane has been installed, then membrane failure is inevitable regardless of its elastic properties.

Top 100 Trusted Brands in Architecture & Design

ARDEX Australia has placed 69th in Architecture & Design’s 2018 Top Trusted Brands Survey. With more than 6,000 votes counted in this years’ survey and over 600 participating brands, the Top 100 reveals those brands most recognised by the industry to uphold a relationship beyond the sale, time and time again.

For the full list of trusted brands, please click here.


Weather and related site effects on liquid membranes

When products are designed and tested for performance, this is done at a set of specified conditions. The standard conditions for laboratory testing are normally set at between 20 and 23 degrees Celsius and 50-55% relative humidity.

In reality, though, the temperature or humidity on site rarely is as in the lab.

To ensure the waterproofing system performs as intended, below are some recommendations to avoid any issues, especially when the temperature and humidity are varying.

Some of the problems
Variances in conditions can affect the waterproofing membranes significantly. For example, a dark substrate in direct sunlight can be ten degrees Celsius higher than the temperature of the air. Being this hot means the waterproofing membrane won’t set and cure as under lab conditions. Likewise, similar failures occur with excess or lack of moisture in the air or in really cold temperatures.

In fact, when the air temperature is below ten degrees Celsius, certain physical changes and chemical reactions when it comes to drying and curing, won’t work. For example, for materials containing Portland Cement (part of cement-polymer liquid membranes) and epoxy resin, the reaction ceases at around five degrees Celsius.

In hot and dry weather, a water borne liquid membrane can lose its water both through evaporation and the substrate. If this happens too quickly, it can lead to holes and voids. This is not acceptable for a membrane. If the day is cool and humid enough, potentially, it may not cure at all, leaving it soft on the inside. And if it freezes when it gets below zero degrees Celsius, then ice crystals can destroy the structure.

Likewise, heat can rapidly speed up the drying and curing process and often can even trap in moisture, by creating a crust but leaving it soft internally.

Wind, airflows, humidity, fog, snow and rain all have their own issues when it comes to using liquid membranes and can severely affect the future performance of the applied waterproofing coat.

Water falling onto waterborne and cement-based membranes can mean they don’t dry properly and potentially can be washed away. Substrate moisture can also lead to bubbles and blisters. Even geography can play a part in how the material reacts. For example, near the coast your surface may be more likely to have a damp sticky film which can interfere with adhesion.

Some solutions that are proven
It’s hard to avoid or control temperature and condition variables. Scheduling works in expected weather extremes should be avoided; however, the following measures can be put in place:

Hot weather

  • All work should be avoided in the heat of the day. Instead, works should be scheduled for evening, early morning or night. The substrates will take some time to cool after extreme highs.
  • Shade the working area(s).
  • Keep all products stored in cool conditions and out of the direct sun.
  • Do not add water to products that are not intended to be diluted.
  • Mix smaller quantities at a time to reduce self-heating.

Cold weather

  • Keep all products stored out of the cold, especially products not intended to be frozen.
  • Warming materials to around 35 degrees Celsius can help but they will go to the substrate temperature rapidly when applied.
  • Use heated tents or enclosures around work areas.

High humidity and wet weather

  • Installation when rain has recently fallen, is currently falling, or is expected to fall soon must be avoided where possible.
  • Check the weather forecasts.
  • Use tents or protection to cover areas to be worked on.
  • Remove water that has accumulated from rain and allow the area to dry.
  • Use fans or driers and ventilation to remove moisture and lower humidity.

Damp substrates

  • Use the correct moisture barrier as a membrane or membrane’s primer.
  • Make sure that below grade drainage is adequate.
  • Prevent water getting into building elements in the first place (protection of parapets.
  • Test for moisture content.

Other important things

  • Several thinner coats of most membranes are better than one or two overly thick coats. This allows more effective drying and curing in general.
  • Aim for the correct film thickness and use the right product for the application.

Click here to read the complete Technical Bulletin.

5 Million Old Tyres Recycled into ARDEX Tile Adhesives

Australia generates millions of used car tyres every year, some of which are recycled and others that are stockpiled.

Tyre dumps and stockpiles present many environmental concerns;

  • They are unsightly
  • Take up valuable land space
  • Cause problems for landfill sites
  • When stockpiled above ground they are at high risk of catching fire which then causes pollutants and toxic gases to be released, oil enters the groundwater and nearby rivers
  • Breeding grounds for pests such as mosquitoes and rodents

Further to this, sand mining is a practice that is fast becoming an ecological problem as the demand for sand is increasing. Sand is mined from beaches, inland dunes and dredged from ocean and river beds, leading to erosion and impacting local wildlife.

The ideal solution is to recycle and reuse the components that make up tyres and at the same time, reduce the need for sand mining.

By doing so, ARDEX has not only recycled over 5 million tyres in its history in Australia, this currently equates to the recycling of over 250,000 used tyres per year, which also saves approximately 3500 tonnes of Australia’s sand per year.

How can ARDEX improve their grout and silicone range?

Your feedback will help shape some new goals going forward into the new year.

ARDEX Grout and Silicone is focused on quality and range and it is most important to us to ensure we are delivering what YOU need.

The following survey has been designed to provide us with feedback on our range, colours, packaging on grouts and silicones so we can set some new goals on delivering you exactly what you want!


The survey should take no more than 10 minutes to complete.

*Survey is open to Australian residents only.

Project in Progress – The Elan, 1 Kings Cross Road, Darlinghurst, Sydney

At 136 meters, 40 stories, The Elan is one of the tallest residential apartment blocks in Sydney. The building is also situated in the highest part of Kings Cross, 45 meters above sea level. Built in 1997, there is 18,200 cubic meters of concrete and 2550 tonnes of reinforcing steel in The Elan.

Consultant: Diagnostech

Builder: Biltbeta


20 years after it was built, The Elan required a complete façade overhaul that included crack and joint repairs, she-blot repairs, spalling concrete, render repair, concrete crack injection, balustrade post repairs and façade coating systems. Furthermore, several balconies required re-waterproofing. ARDEX Australia in conjunction with the consultant specified a wholistic solution that included a complete, fully warrantable SystemARDEX approach. Works commenced in May 2016 and are expected to be completed early 2018. The size of the building makes it one of the largest façade restoration projects currently in Sydney.


Before work on the façade coating could start, concrete repairs were essential on parts of the building. Spalling concrete and she-bolt hole repairs were rectified with ARDEX BR 345 MICROTEC® Fibre-Reinforced, High Resistivity, Polymer-Modified, Structural Concrete Patching and Repair Mortar and ARDEX BR 120 FC Polymer-Modified, Fibre-Reinforced Fairing Coat.

Areas that were affected by cracks in concrete were reinstated by using ARDEX RA 88 Multi-Purpose Epoxy Repair Adhesive to adhere ARDEX T-Ports, a unique pressure injection port system, before injecting ARDEX RA 142 Super Low Viscosity Structural Concrete Crack Injection Epoxy for hairline cracks and ARDEX RA 144 Low Viscosity Structural Concrete Crack Injection Epoxy for cracks that were wider than 1mm.

For render repairs, ARDEX WR Prime Performance Enhancing Polymer Primer & Additive was used in conjunction with ARDEX WR 100 General Purpose Acrylic Render.

There was a large number of joints that needed to be repaired and re-sealed. Throughout the project, a range of ARDEX sealants were used in including ARDEX CA 20 P Multipurpose Construction Adhesive and Sealant, ARDEX RA 030 One Component, Moisture-Curing Expansion Joint Sealant and ARDEX RA 040 Polyurethane Joint Sealant.

The specified façade coating system included the use of two coats of ARDEX WPM 300, a two-component water based epoxy polyamide membrane/barrier coating, followed by two coats of ARDEX WPM 330 External Anti-Carbonation Facade Membrane.


Unique Elements

Due to the size of the structure, there was a significant amount of product required to coat the façade. In total, there are approximately 35,000 litres of WPM 300 and an additional 35,000 litres of WPM 330 that were used for the façade coating system.

ARDEX Australia Continues Partnership with McGrath Foundation

ARDEX Australia has been a corporate partner of the McGrath Foundation for over two years and during this time is very proud of the support that customers, suppliers and employees have made to this excellent cause.

This October, ARDEX is continuing its support of the McGrath Foundation by making a contribution to the Foundation from the sales of a selection of the tiling Choose Your Solution range (X 17X 18X 77 and X 78) as well as parts of the flooring Choose Your Solution range (K 220K 10 Reactiv8K 12 and K 15). During the partnership so far, over $100,000 has been contributed to the McGrath Foundation which assists the McGrath Foundation in supporting families experiencing breast cancer with breast care nurses throughout Australia.

ARDEX is encouraging retail partners to pink up stores in support of Breast Cancer Awareness Month and would love for you to contact us if you would like to get involved. We will provide you with decorations and signage to pink up your store, email us here to get involved!

McGrath Breast Care Nurses have supported over 36,000 families across the country and the team at ARDEX are looking forward to contributing to such an esteemed Australian charity. Help make a difference today by donating at http://mcgrathfoundation.gofundraise.com.au/page/ardexaustralia or contact your local ARDEX representative on how you can get involved.

Top 100 Trusted Brands

Thanks You for your Nomination

ARDEX would like to thank Architecture and Design customers who nominated ARDEX Australia as one of the most trusted brands in 2016. There were 341 brands considered in the survey and 13,456 votes from the architecture, building, construction and design industries determined the winners.

The survey revealed that the most common themes associated with trusted brands were great service, products and reliability – in addition to being a socially driven eco-friendly company with Australian made products.

The Top 100 Trusted Brand Survey was established in 2012 and is Australia’s leading national showcase of the best brands within the Building and Architectural arena. Brands compete for recognition in 25 categories that highlight innovation, application or quality in a particular area.

ARDEX Australia is proud to add this achievement (58th Most Trusted Company) to the Financial Review’s Most Innovative Company Award where ARDEX Australia achieved the 28th Most Innovative Company in 2016.