Australia’s construction industry is no stranger to code updates, but NCC 2025 carries a change that will have genuine, practical consequences for anyone involved in below-ground construction — certifiers, designers, builders, and product suppliers alike. For the first time, a single Performance Requirement — F1P1 — will govern all water management for Class 2–9 buildings, both above and below ground. The mechanism that makes this work is deceptively simple: a new defined term, “water”, in Schedule 1.

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Read the white paper to understand the new compliance requirements for below-ground structures and the practical implications for certifiers, designers, builders, and material suppliers.

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Choosing between a tanked or drained basement design is not as easy as taking the cheapest option; it’s a high-stakes decision that dictates the lifespan of your structure. The cost difference during construction is often a healthy six-figure sum for the developer for even mid-size developments, and potentially an ongoing maintenance cost for the eventual owner or owners.

At Waterproofing Integrity, the bathtub analogy is one we use regularly. Treat your basement like a bathtub. Either have a continuous structure that prevents water getting in or allow water to enter and drain it effectively.

The right strategy requires complex coordination between architects, builders, consultants, council mandates, and site-specific considerations— all while considering how that space is designed and will actually be used. Whether you’re designing for a high-end office, media room, laboratory or a car park, the wrong call at the design stage leads to more than just damp walls—it leads to costly disputes, loss of use of the space and can impact the health and amenity of those using the space.  

Don’t wait for the mould to tell you that the basement needed more attention during design and construction.

Water is the most patient trespasser on your site; it always finds a way, so we make sure it’s the way out.

Water will find every microscopic flaw in a basement’s construction whether that be through a shoring wall, a poorly sealed joint, and every shortcut taken during construction. Because concrete is naturally porous, it cannot be relied upon solely as your waterproofing strategy. Due consideration needs to be given to a solution that respects the intended use, design and specific site conditions—not just a “standard” fix.

So Waterproofing Integrity recommend not to treat waterproofing as an afterthought, unless you want to end up with a basement that feels more like a swamp than a structural asset. 

Stop the leak before it starts, because an ‘Indoor Swimming Pool’ should never be a surprise feature of your basement.

From 2026, the National Construction Code (NCC) will require basement waterproofing considerations to be factored in design from residential properties to large commercial developments. This requirement was previously exempt from the NCC which often meant water management was not always a key discussion point in design.

At Waterproofing Integrity, our team of structural engineers and waterproofing industry professionals look at each basement for how it is designed, how it will be used, where it is located and the site specific considerations. From that we advise on the best approaches for your site to provide confidence and peace of mind!

Please reach out to us using our contact form and we will be happy to assist you further.

The Property Developers Act 2024 (ACT) is new legislation introduced by the ACT Government to tighten control over how property development is carried out in the Territory. It was created in response to ongoing concerns about poor‑quality construction, building defects, and consumers being left without practical recourse when things go wrong.

At its core, the Act is about who is allowed to develop property, how they must operate, and how long they remain responsible for what they build.

What is the Property Developers Act 2024?

The Property Developers Act 2024 is a comprehensive regulatory framework that applies to people and companies who develop residential property in the ACT. Its key objectives are to:

• Lift the standard of residential development in the Territory
• Make it harder for “phoenix” developers to walk away from defective projects
• Give purchasers and owners clearer rights and longer timeframes to pursue claims
• Align developers’ incentives with long‑term building performance, not just short‑term profit

To achieve this, the Act introduces a licensing scheme for developers, sets out ongoing compliance obligations, and significantly extends how long developers can be held responsible for defects.

Who does the Act apply to?

The Act typically applies to:

• Property developers who undertake, arrange, or manage residential development projects in the ACT
• Company directors and officers involved in development entities
• Related parties who might otherwise try to hide behind complex company structures

It is particularly relevant to multi‑unit residential projects (such as apartments and townhouses), where the consequences of defects are often widespread and expensive to fix.

How does it regulate developers?

The Act regulates developers in three main ways:

1. Licensing and registration
   Developers must be licensed to operate in the ACT. This means they are vetted for:
   • Financial capacity
   • Fit‑and‑proper‑person criteria
   • Relevant experience and competency
2. Ongoing monitoring and compliance
   Licensed developers must comply with conditions that can include:
   • Keeping adequate records
   • Cooperating with inspections and audits
   • Ensuring projects are delivered in line with approved plans and legislation
3. Accountability and enforcement
   The regulator is given stronger tools to:
   • Suspend or cancel licences
   • Issue penalties and enforcement notices
   • Pursue directors personally in certain circumstances

Key Provisions of the Act

Mandatory Licensing Requirements

Under the Act, all property developers operating in the ACT must hold a valid licence. This ensures that only vetted and accountable entities can undertake development activities. The licensing regime includes:

• Stringent eligibility criteria for applicants
• Financial capacity assessments
• Professional competency requirements
• Ongoing compliance obligations

Enhanced Building Standards and Documentation

While builders and certifiers still have their own obligations, the Act pushes responsibility up the chain so that developers cannot simply blame others. Developers must be able to demonstrate that:

• Appropriate design, supervision, and quality assurance processes were in place
• Construction complied with the Building Code and relevant Australian Standards
• Critical elements (such as structure, fire safety, and weatherproofing) were properly documented and verified

This includes more rigorous expectations around how systems like waterproofing are specified, installed, and recorded.

Extended Liability Periods

One of the most significant aspects of the Act is the extension of liability periods for construction defects. Developers now face:

• 10‑year liability for major structural defects (including serious waterproofing failures that affect structural performance or safety)
• 6‑year liability for non‑structural defects that affect the building’s functionality
• 2‑year liability for minor defects

These extended timeframes recognise that many defects, particularly water ingress issues, may not become apparent immediately after completion.

Why this matters for building performance (and waterproofing)

Before looking specifically at waterproofing, it is important to understand the intent: the Act is designed to link financial and legal responsibility to long‑term building performance. That naturally draws attention to high‑risk areas like waterproofing, cladding, and structure, because these are the elements that most often lead to expensive, complex disputes when they fail.

The Growing Problem of Leaking Buildings

Water ingress and leaking buildings have become an epidemic in modern construction, causing billions of dollars in damage across Australia. Common causes include:

• Inadequate or improperly installed waterproofing membranes
• Poor detailing around penetrations and junctions
• Use of substandard materials to reduce costs
• Insufficient oversight and quality control during construction
• Failure to comply with Australian Standards

The consequences of water ingress extend far beyond aesthetic concerns. Leaking buildings can experience:

• Structural deterioration and concrete cancer
• Mould growth affecting occupant health
• Degradation of internal finishes and fixtures
• Significant devaluation of property
• Costly and disruptive remediation works

Enhanced Liability Under the Act

The Property Developers Act 2024 significantly strengthens the legal position of affected property owners by:

Personal Liability for Directors

The Act can impose personal liability on company directors and officers where poor‑quality construction results from deliberate cost‑cutting, negligence, or failure to implement adequate quality control measures. This provision prevents developers from simply liquidating companies to avoid responsibility for defects.

Statutory Warranties

Developers must provide statutory warranties that their buildings are:

• Constructed in accordance with approved plans
• Fit for habitation and suitable for their intended purpose
• Constructed with proper materials and in a proper manner
• Compliant with all relevant building codes and standards

These warranties are automatically implied and cannot be contracted out of, providing robust protection for purchasers.

Penalties for Non‑Compliance

The Act introduces substantial penalties for developers who fail to meet their obligations:

• Significant financial penalties for breaches of licensing conditions
• Suspension or cancellation of development licences
• Criminal liability for serious breaches involving fraud or gross negligence
• Public disclosure of enforcement actions

What This Means for Property Owners

If you own or are considering purchasing a property in the ACT, the Property Developers Act 2024 provides you with:

• Greater protection against defective construction work
• Extended timeframes to identify and pursue claims for building defects
• Multiple avenues for seeking remedies, including direct action against developers
• Increased accountability from developers who can no longer hide behind corporate structures

The Importance of Quality Waterproofing

Given the enhanced liability framework, developers are now under greater pressure to ensure proper waterproofing from the outset. Quality waterproofing systems are essential because:

• Water ingress is one of the most common and costly building defects
• Remediation costs often far exceed the cost of proper installation initially
• Developers now face extended liability periods, making quality work a financial imperative
• Waterproofing failures can trigger other defects, compounding liability

Professional waterproofing should never be viewed as an optional extra or an area to reduce costs. It is a critical building element that protects the structural integrity of the building and the health and safety of its occupants.

What to Do If You Have a Leaking Building

If you suspect water ingress or have identified leaks in your property:

1. Document everything: Take photographs, keep records of when leaks occur, and note any related damage
2. Engage qualified professionals: Obtain independent assessments from licensed building inspectors and waterproofing specialists
3. Notify the developer: Provide formal written notice of the defects within the liability periods
4. Understand your rights: Familiarise yourself with the protections available under the Property Developers Act 2024
5. Seek legal advice: Consider consulting a construction lawyer if the developer is unresponsive or disputes liability

The Role of Professional Waterproofing Services

Professional waterproofing specialists play a crucial role in both preventing and remedying water ingress issues. Services include:

• Pre‑construction waterproofing design and specification
• Installation of compliant waterproofing systems
• Independent inspections and quality assurance during construction
• Diagnostic investigations to identify the source of leaks
• Remedial waterproofing and building restoration
• Expert reports for legal proceedings

Engaging qualified waterproofing professionals ensures compliance with Australian Standards and the requirements of the Property Developers Act 2024, protecting both developers from liability and building owners from defects.

Conclusion

The Property Developers Act 2024 (ACT) marks a watershed moment in construction regulation and consumer protection. By dramatically extending liability periods and increasing accountability, the Act sends a clear message: poor‑quality construction, particularly involving waterproofing failures, will no longer be tolerated.

For property owners, this legislation provides powerful tools to pursue remedies for defective building work. For developers, it creates strong financial incentives to prioritise quality construction and proper waterproofing from the outset.

As the construction industry adapts to this new regulatory environment, the emphasis on quality waterproofing and compliance with building standards has never been greater. Whether you’re a developer, property owner, or construction professional, understanding the implications of the Property Developers Act 2024 is essential for navigating the evolving landscape of construction liability in the ACT.

For expert advice on waterproofing compliance, remediation, or building defect investigations, contact those who understand the requirements of the Property Developers Act 2024 and can help protect your interests. Contact Waterproofing Integrity on 1300 025 944 or advice@waterproofingintegrity.com.au. Waterproofing Integrity are working with Canberra’s leading builders and developers on projects capturing hundreds of apartments and can assist you in your project.

Waterproofing Integrity Brisbane is now operational, primarily focused on South-East Queensland around Brisbane, the Gold Coast and the Sunshine Coast but with the capacity to cover Tweed Heads, Byron Bay and Northern NSW and greater Queensland including Townsville, Cairns, Rockhampton and Bundaberg.

Well regarded industry professional Kieran Biber will lead Waterproofing Integrity’s Brisbane Office and bring 25 years of combined experience in waterproofing. Waterproofing Integrity Brisbane will be able to assist with waterproofing design compliance advice, basement waterproofing design, performance solutions and onsite waterproofing inspections.

In the first twelve months of operations, Waterproofing Integrity are already working with Top Tier builders on key projects in Brisbane in both new construction and remedial works.

Kieran started with Waterproofing Integrity in August 2023 having spent over eight years with Sika which included being the Queensland State Sales Manager and then overseeing its waterproofing range. Prior to that Kieran had worked as a builder and waterproofing contractor before representing material suppliers Parchem and Dayton Superior. Kieran stated, “I had been considering moving into consultancy for some time. I had met with David (Previte) and his team in the past in my time at Sika and really liked what they were doing in Sydney. When I heard that they were starting to work on projects in Queensland, we started chatting and it seemed like a good fit in establishing Waterproofing Integrity in Brisbane.”

Kieran’s qualifications include a Cert IV in Building, Certificate III in Construction Waterproofing, Certificate III in Wall and Floor Tiling, Certified Surveyor of Structural Waterproofing (CSSW) for basement waterproofing design, Certificate III in Concreting and Certificate IV in Training and Assessment as he provides training regularly for the Master Builders Association.

Kieran is otherwise an active participant in the waterproofing industry having held positions with the Australasian Concrete Repair Association (ACRA) for which he has been Queensland President from 2020, a Committee Member of the Australian Institute of Waterproofing (AIW) and contributes to the review of Australian Standards. Kieran is currently reviewing the external waterproofing Standard AS4654.2 and also AS4654.1 as part of the BD-038 committee and also on the ME-094 Mould restoration committee.

”I am thrilled to announce the expansion of Waterproofing Integrity into the Brisbane market and honored to be the face of the company for Queensland. With the upcoming infrastructure projects for the Olympics and a significant rise in coastal remedial work, this is the perfect time to transition into consultancy and support the local industry. I am confident that the future is bright for Waterproofing Integrity in Brisbane, and the demand for waterproofing consultancy has never been higher.”

With the domestic and international migration into South-East Queensland there is ongoing demand for housing in the form of apartments including Build to Rent (BtR), student accommodation and social housing; hospitals and health; hotels and of course the infrastructure and public spaces that comes with the 2032 Brisbane Olympic Games. While much of this focus may be in Brisbane, Waterproofing Integrity are positioned to assist in the development of the neighbouring growth areas on the Gold Coast to the south, Sunshine Coast to the north and Springfield near Ipswich to the west.

The Waterproofing Integrity Brisbane office can be contacted at brisbane@waterproofingintegrity.com.au

In the world of waterproofing contracts, substrate acceptance clauses are often an overlooked detail, but their relevance to liability cannot be overstated. A drain point underneath a planter box wall, as depicted in the photo accompanying this discussion, is an example of an unacceptable condition for applying a waterproofing system. Competent waterproofing professionals recognise this and understand the significant implications of applying a waterproofing membrane to an unsuitable substrate.

Why Substrate Acceptance Matters

Substrate acceptance is not just about technical compliance; it’s about ensuring the integrity and longevity of the entire waterproofing system. Accepting a substrate without proper inspection can lead to severe liability issues for the waterproofing contractor.

1. Foundation of Success 🛠️

A properly prepared substrate ensures that the waterproofing membrane adheres correctly and functions as intended. Any deficiencies or imperfections in the substrate can compromise this performance, leading to premature failure of the waterproofing system.

The Technical Perspective: From a technical standpoint, a substrate in poor condition can lead to inadequate adhesion of the waterproofing membrane. This inadequacy can cause blisters, delamination, and subsequent water ingress, which are detrimental to the integrity of the structure.

The Liability Perspective: If the waterproofing contractor proceeds without addressing substrate issues, they implicitly accept the state of the substrate. This acceptance can lead to significant liability if the system fails due to substrate problems. Contractors become responsible for the additional costs associated with repairs and potential legal consequences.

2. Extended Durability ⏳

High-quality substrate preparation is crucial for the long-term durability of the waterproofing system. A well-prepared substrate minimizes the risk of leaks and water damage over time.

Durable Outcomes: A properly prepared substrate supports the membrane’s durability, ensuring it can withstand environmental and operational stresses. This preparation helps prevent common issues such as cracking, bubbling, and water penetration.

Prolonged Liability: When a waterproofing system fails prematurely due to substrate issues, the contractor can face prolonged liability. This includes covering repair costs, potential penalties, and reputational damage. Ensuring substrate quality upfront can mitigate these risks and protect the contractor’s professional reputation.

3. Accountability 📜

Accepting the substrate means the contractor vouches for its suitability. Any subsequent issues due to substrate problems typically fall squarely on the contractor’s shoulders.

Written Documentation: Proper documentation and communication about substrate issues are essential. Contractors must note any deficiencies and seek written approval to proceed from stakeholders. This documentation can act as a shield against liability if substrate issues arise later.

Legal Ramifications: Failing to document substrate issues can lead to legal complications. Contracts often include clauses holding the contractor accountable for substrate complications. Without proper documentation, proving that the substrate was unfit at the time of application can be challenging, leading to unfavourable legal outcomes.

Mitigating Risks in Substrate Acceptance

Minimising liability and ensuring successful waterproofing applications involve detailed inspections, thorough documentation, clear communication, and ongoing education.

1. Thorough Inspection 🔍

Conducting meticulous inspections of the substrate before application is vital. Contractors should diligently look for issues like cracks, uneven surfaces, or moisture content that could compromise the membrane.

Inspection Protocols: Establishing a robust inspection protocol can help identify potential substrate issues. Using tools such as moisture meters, laser levels, and visual inspections can ensure comprehensive assessment.

Liability Safeguards: Accurate and thorough inspections safeguard against liability. Identifying and addressing substrate issues before membrane application can prevent future claims and disputes related to substrate acceptance.

2. Documentation 📸

Documenting inspections and findings is crucial. If issues are identified, communicating them to stakeholders and recommending necessary rectifications is essential before proceeding.

Visual Records: Taking photographs and creating detailed reports of substrate conditions serve as valuable records. These documents can be referenced if disputes arise regarding substrate suitability.

Stakeholder Agreements: Ensuring that all necessary rectifications are agreed upon and documented before proceeding binds stakeholders to a mutual understanding, reducing the contractor’s liability.

3. Clear Communication 🗣️

Explicitly stating the importance of proper substrate preparation in contracts and outlining steps to be taken if the substrate is found unsuitable is fundamental.

Contract Clauses: Including well-defined substrate acceptance clauses in contracts can protect contractors. These clauses should outline the protocols for substrate inspection, documentation, and necessary rectifications.

Effective Communication: Engaging in clear and continuous communication with all parties involved ensures everyone acknowledges the criticality of substrate conditions. This transparency can prevent misunderstandings and liability issues down the road.

4. Training & Education 📚

Ongoing education of the team on best practices for substrate preparation and the risks associated with inadequate preparations is crucial.

Continuous Learning: Establishing continuous learning programs that focus on the latest techniques and standards in substrate preparation ensures that the team is equipped with the necessary knowledge.

Risk Awareness: Instilling a culture of risk awareness can lead to better decision-making at all levels. This awareness can help the team understand the stakes involved and the importance of meticulous substrate preparation.

5. Independent Third-Party Inspection 🔍

Engaging a competent waterproofing quality technician from outside your organization to conduct an independent review can provide an objective assessment of the substrate’s condition.

Objective Assessment: An independent third-party inspection offers an unbiased evaluation of the substrate, ensuring that any issues are identified without internal pressures or conflicts of interest. This objective perspective can be invaluable in confirming that the substrate meets the required standards.

Expert Recommendations: These inspectors can provide expert recommendations for rectification if any issues are found, ensuring the best possible outcome for the waterproofing application. This expert advice can lead to better decision-making and adherence to best practices.

Reduced Liability: Having an independent third-party inspection documented can further protect against liability, as it demonstrates a commitment to quality and due diligence. This additional layer of scrutiny reinforces the thoroughness of your approach, minimizing potential risks and enhancing the project’s success and your credibility.

Conclusion

By taking proactive steps such as thorough inspections, detailed documentation, clear communication, ongoing education, and independent third-party inspections, waterproofing contractors can safeguard not just the integrity of their projects but also their professional reputation. Substrate acceptance clauses, while often seen as minor details, carry significant weight in determining liability and ensuring the success and durability of waterproofing systems.

Following the growth of Waterproofing Integrity over recent years, we are pleased to announce we now have a dedicated team operating from our Newcastle office. The team will service areas north of Sydney to the Queensland border including the Central Coast (Gosford), Newcastle and Greater Hunter Area, and growth centres such as Forster, Port Macquaire, Coffs Harbour, Dubbo and Tamworth.

Nathan Davidson leads our team in Newcastle and brings over 25 years of waterproofing experience and knowledge with him for our clients. We are currently experiencing rapid growth in Newcastle and currently expanding our team.

Nathan has owned and operated a leading and dynamic waterproofing company, NJD Corp, which has serviced Newcastle, Central Coast, North Coast & Central West for the last 25 years. With many years of experience and a hands-on approach, Nathan brings a broad knowledge of construction waterproofing, strata and remedial works with him. Nathan’s insights, experience, knowledge and network of clients allows Waterproofing Integrity Newcastle to offer its service more effectively to the region.

Nathan also has various qualifications including a Bachelor of Business, Diploma of Building & Construction, a Certificate III in Construction Waterproofing and has been a licenced waterproofing contractor for the last 25 years. Nathan and his team come with years of experience in waterproofing design and construction application with a practical understanding of compliance, design considerations, products and performance.

In recent years Nathan has made the move into consulting to allow him to utilise his knowledge that he has acquired over many years in the industry to assist clients and provide waterproofing solutions. Some examples of major projects that Nathan has worked on over the years include but not limited to the Newcastle Mater Hospital Redevelopment (Abi Group), McDonald Jones Stadium Redevelopment (John Holland Group), Sky Residences (GWH Build), Darby Plaza (GWH Build), RAAF Base Williamtown Redevelopment (Lendlease) and the WesTrac Tomago Industrial Complex (Abi Group), Fresh Hope Residential Aged Care Greenhills (Richard Crookes Constructions), East End Newcastle Redevelopment (Richard Crookes Constructions), Gosford Hospital Redevelopment (Richard Crookes Constructions), Tamworth Hospital Redevelopment (lend Lease) . The region is continuing to experience rapid growth and a high demand for construction in the area.

Having already worked with a number of leading construction contractors, architects, developers and strata companies in the area, Nathan and his team will continue the design and testing services that Waterproofing Integrity have already provided to projects in Newcastle, Gosford and the Central Coast, Maitland, Forster, Port Macquarie, Dubbo, Tamworth and other Regional Centres to date from Sydney.

Nathan and his team are looking forward to assisting the wider region as it continues to experience rapid growth and the challenge this offers moving forward. Consulting is an area that has always been of interest to Nathan and he is looking forward to a new challenge. Waterproofing Integrity Newcastle allows him to apply his knowledge and many years of experience to achieve positive outcomes for developers, builders, architects and asset owners throughout Northern NSW.

The Waterproofing Integrity Newcastle office can be contacted on 02 4926 5654 or email newcastle@waterproofingintegrity.com.au

The Complexity Conundrum: Hobs, Setdowns, and Falls in Structural Concrete

I’ve recently come across a thought-provoking quote by Clyde Fitch: “Complexity creates a maze between you and success.” This quote resonates strongly with me when considering the intricate surface profiles of structural slabs compared to the simplicity of a flat slab. While there are undeniable benefits to a complex structural profile, it’s crucial to consider whether we are inadvertently increasing the list of potential issues that could lead to the failure of the waterproofing system.

The Benefits and Challenges of Structural Falls and Hobs

Incorporating hobs and structural falls ensures that wet areas can effectively contain and shed water to the drain, reducing the sole reliance on the waterproofing membrane for performance. However, achieving this level of precision requires a skill set that is often considered uncommon among concretors. The hectic nature of a concrete pour can further complicate the process, increasing the likelihood of errors and inconsistencies.

The Flat Slab Alternative: Building Falls in a Controlled Manner

An alternative approach worth considering is pouring a flat structural slab and subsequently building up the falls and upturns using carefully selected products in a more controlled manner. This method allows for greater precision and attention to detail, minimizing the potential for errors that could compromise the waterproofing system’s integrity.

By utilizing topping products after the structure is complete, professionals can create the necessary falls and upturns with greater control and accuracy. This approach not only simplifies the initial structural concrete pour but also allows for a more focused effort on ensuring the proper slopes and drainage patterns are achieved.

Weighing the Options: Simplicity vs. Complexity

As waterproofing design professionals, it is our responsibility to carefully evaluate the trade-offs between the benefits of a complex structural profile and the potential risks associated with its execution. While hobs and structural falls offer inherent advantages, the skill required to achieve them consistently and accurately may not always be readily available.

On the other hand, the flat slab alternative, coupled with a controlled build-up of falls and upturns, provides a more manageable and reliable approach to ensuring effective water management. By simplifying the initial structural concrete pour and focusing on the precise creation of falls and upturns afterward, we can reduce the potential for errors and increase the likelihood of a successful waterproofing system.

The Path to Success: Choosing the Right Approach

Ultimately, the decision between a complex structural profile and a flat structural slab with controlled fall build-up depends on various factors, including the project’s specific requirements, the skill level of the construction team, and the available resources. As professional consultants, our role is to assess these factors and recommend the approach that offers the best balance of effectiveness, reliability, and practicality.

By carefully considering the potential challenges and benefits of each approach, we can guide our clients towards a waterproofing solution that not only meets their needs but also minimizes the risk of failure. In the end, the path to success in waterproofing may lie in embracing simplicity and control, ensuring that the maze between us and a successful outcome is as straightforward as possible.

Written by: David Previte

www.linkedin.com/in/davidprevite

https://www.youtube.com/@DavidPrevite-WaterproofExpert

Liquid membranes are extensively utilised throughout Australia in a variety of contexts, including internal wet areas, balconies, subterranean applications, and even as UV-exposed rooftop membrane systems facing intense UV conditions, which demand robust and durable waterproofing solutions.

In the ever-changing landscape of liquid membrane technologies, it can be challenging to determine the most suitable system or technology for specific applications. This article aims to shed light on Wet Film Thickness (WFT) and Dry Film Thickness (DFT) concepts, paving the way for a deeper discussion on membrane applications in a subsequent article.

• WFT = Wet Film Thickness
• DFT = Dry Film Thickness

Every liquid membrane has a specific solids content (typically between 40-80%), in simple terms this means that the remaining percentage of the membrane will typically evaporate during the curing process.

As an example, if a membrane is applied at a rate of 800 micron (0.8mm) per coat and is 50% solids, once the membrane has cured you will be left with a coating that is 400 micron (0.4mm). This seems quite technical and you’re probably thinking to yourself “why do I need to know all this information, I’ll just slap it on nice and thick and it’ll be fine”- incorrect.

Many membranes I test for finished DFT (Dry Film Thickness) are well under the requirements and the applicators have stated they went real thick with the application.

Manufacturers should always specify the required DFT on their product’s technical data sheet. This specification is essential because each membrane must pass certain standards, such as AS4858 for internal wet area use or AS4654.1 for external above-ground use. The sample thickness used for these tests must be the minimum DFT applied in real-world scenarios.

It’s not uncommon in the market for manufacturers to test a product at a higher DFT (1.5-2mm) to achieve satisfactory results and on the technical data sheet state that it can be applied at lower DFT’s eg: 0.8=1.0mm. This is not deemed as a compliant application of the membrane.

Whatever sample thickness was used for the test results must be the minimum DFT the product can be applied at as there is no data/backing to confirm the membrane would work at a lower applied thickness.

The video below contains a brief demonstration of how to use a Wet Film Gauge.

Now that we’ve covered off on how critical it is to achieve the correct WFT/DFT for liquid membranes, lets cover off on the easiest ways to help achieve this on site:

1. Wet Film Thickness Indicators/combs: Using a wet film thickness comb is a great way to confirm that you’re applying the membrane at the correct thickness whilst it is wet, this approach also offers the advantage of allowing for adjustments; if the initial application is too thin, more membrane can be added promptly to prevent potential problems in the future.
2. Measuring the Application Area: A simple yet efficient strategy involves measuring the area where the membrane will be applied and calculating the product consumption per coat. For instance, if the technical data sheet of a membrane specifies coverage of 20m2 per 15L pail per coat, you can delineate areas of 20 square meters to ensure correct usage. Even with this method, it’s still advisable to verify the wet film thickness using a gauge to ensure accuracy and consistency in the application.
3. Ultrasonic Film Thickness testing: Once the membrane has been applied and is fully cured, ultrasonic film testing can be undertaken. This is specialised equipment that can provide the DFT of the membrane in a non-destructive manner. Ultrasonic testing is typically effective on various forms of membranes and is commonly performed by waterproofing inspectors, certifiers, and similar professionals to ensure compliance and quality.

I hope this information enhances your understanding of the significance of membrane thicknesses and provides insight into how to effectively implement testing methods for compliance in your upcoming waterproofing projects.

This presentation recording is your essential guide to under and over screed waterproofing in Australia for 2023. Prepared by the Australian Institute of Waterproofing and delivered by David Previte.

The following items are covered in the presentation:

• Introduction 00:00
• Regulations 01:20
• Substrate 08:23
• Protection 11:58
• Tile Replacement 13:29
• Junction Detailing 14:57
• Overlay Bonding 21:02
• Accountability 25:41
• Mould & Bacteria 28:26
• Creating Falls 32:00
• Floor Heating 33:15
• Program 34:57
• Wall Sheet Warranty: 35:55
• Case Studies 37:00
• Under & Over Problems 47:23
• No Waterproofing? 50:06
• The Final Solution 52:35

IMPORTANT NOTE: due to time limitation I have not covered the compliance pathways for a waterproofing system that is applied both under and over the screed bed. As it is not specifically covered in AS3740:2021 and the issues that may arise, the dual system may require validation as a Performance Solution. We start with an overview of Australian regulations, ensuring you understand the legal framework and compliance requirements for your waterproofing projects. Next, we delve into the heart of waterproofing methods, evaluating the strengths and weaknesses of both under and over screed options. Our detailed analysis offers insights into material selection, application techniques, and how to navigate the pros and cons of each method within the context of Australian standards. Concluding with a forward-looking perspective, we explore the innovative approach of integrating both under and over screed waterproofing. This dual system presents a comprehensive solution but comes with its own set of challenges. We cover these pitfalls thoroughly, equipping you with the knowledge to implement effective waterproofing strategies that are both resilient and compliant. Whether you’re a seasoned builder, an architect, or a homeowner planning a project, this video provides invaluable insights into making informed decisions on waterproofing in Australia. Join the conversation and share your thoughts in the comments below. #AustralianWaterproofing, #ScreedWaterproofing2023, #UnderOverScreed, #ConstructionRegulationsAU, #WaterproofingSolutions, #AustralianStandards, #StandardsAustralia #HomeImprovementAU, #ProfessionalBuildersAU, #ConstructionTips2023, #AustralianDIYProjects

One of the typical areas of concern that I come across regularly on site is, without a doubt, membrane application in conjunction with sealants. To explain the applications, this is regarding Class III bond breaker/fillet joints at:

• Floor-to-wall or wall-to-wall junctions
• Expansion joint details
• Window threshold membranes requiring a joint sealant from the window to the membrane; and
• Membrane termination details; just to provide examples.

People regularly say, ‘just put some Sikaflex in it’ or ‘throw some PU in there’ and think that this is perfectly fine and compliant. As a supplier, I can state that we sell multiple types of PU sealants (and membranes) and that if we could have only one type of sealant to do all applications don’t you think we would simplify what we offer to the market? Not all sealants are the same! Whether it’s chemical composition, or the physical properties of the product, they all react and perform differently, and you should consult your local manufacturer on what is the most suitable product for the application you are undertaking.

Curing – This would have to be the most common defect that is seen throughout the market. Typically, a PU sealant will ‘tack off’ within a couple of hours but only 1-2mm will cure on the first day. Generally, a fast cure PU sealant will take a couple of days to reach full cure. This is completely dependent on the thickness of the application so expect to allow more time if you’re filling larger gaps with the product. Now how many job sites do you really see the sealant left for multiple days before membrane application? It’s a scary thought.

There are plenty of ‘MS polymer’ or ‘solvent free’ PU sealants on the market these days; regardless of the technology they all generally release some form of biproduct during the curing process and most importantly must be left to fully cure. Regularly, I hear from contractors that using a solvent free sealant means they can install the membrane quicker; this is not the case, it may not gas and cause bubbling of the membrane, but you still must allow for full cure of the sealant before membrane application, no exceptions. Therefore, if you are waiting for full cure of the sealant, does the technology of what is being installed really matter? Food for thought.

Applying a membrane over a sealant before it’s fully cured typically can cause two main issues:

1. The sealant is still gassing and will retard the membrane from curing; this causes bubbles/blisters in the membrane and even if it eventually cures and membrane is now defective.
2. If the membrane is applied over the sealant too quickly, the sealant may run the risk of not curing completely. Most sealants are moisture curing, so with no access to moisture/atmosphere, as it’s sealed from a membrane, the curing reaction will slow down and eventually stop. I’ve been on various sites where sealant details/joints have been cut out 6 months after installation and the sealant is still uncured once you cut into the surface.

Window Thresholds – This is an area of concern that needs to be addressed nationally. Most contractors think that a water-based membrane and a PU/MS sealant is all that’s required. Sometimes this is the case, but contractors/builders need to realise that not all water-based membranes are the same. SBR/Latex membranes really don’t like PU sealants and typically require primers for adhesion, water-based PU acrylic membranes typically adhere well but UV stable versions of these membranes with titanium dioxide and certain pigments can perform very differently and require primers for adhesion in some instances. In summary, the only membrane and sealant that should be used on a window threshold is the one where a supplier can provide an ‘adhesion test report’ showing adhesion and compatibility testing between the two materials otherwise you are taking the ownership on and this can end up being a costly exercise.

Key Message – Compatibility Is King!

Contractors are not chemists and aren’t expected to know all the answers; utilise your product supplier’s knowledge and only use tested systems to mitigate liability.

Contributed by Kieran Biber – Consultant – Brisbane

This article originally appeared in the Australian Institute of Waterproofing Newsletter, Issue 18, November 2021