Remedial Waterproofing Service Sydney


Waterproofing is crucial for any construction project, whether residential or commercial. Proper waterproofing prevents water penetration or water ingression which can cause structural damage, mould growth, and other issues. Without adequate waterproofing, a building can deteriorate quickly and become uninhabitable.

At MJ Engineering, we specialise in remedial waterproofing services to repair existing failed waterproofing systems. We understand the importance of proper waterproofing in construction projects to prevent water damage, structural deterioration, and potential health hazards such as mould growth. Our experienced team has the expertise to identify the underlying cause of waterproofing issues. We provide a comprehensive solution that includes diagnosing the issue and providing a specification to prevent future water penetration.

Remedial Waterproofing Repair Process


Site Inspection & Report

We will inspect the area where water ingress is reported to areas adjacent/below; provide initial findings.


Develop Specifications

We would develop specifications describing methodologies and materials required to repair the issue.


Conduct Tender Process​

We would conduct the tender process on behalf of the owners corporation and assess the tenders.


Project Management

We will project manage / superintend the repair works and ensure the project runs according to the budget and schedule.


Options for Waterproofing Repair

When it comes to waterproofing repairs, there are several options available. If the damage to the waterproofing system is not too severe, it may be possible to repair the existing system. This is often the most cost-effective approach, as it involves fixing the current system rather than replacing it entirely. Repairs can include patching up cracks or holes, sealing gaps, and re-applying waterproofing products.

If the existing waterproofing system is beyond repair or if a partial replacement would not be effective, a full system replacement may be necessary. While this can be costly, ensuring that the building is adequately protected from water intrusion is often necessary.

How can MJ Engineering Projects help?

Our Experience

At MJ Engineering, we understand the importance of waterproofing in construction projects, and that’s why we offer remedial waterproofing services that repair existing failed waterproofing systems. Our team of certified waterproofing consultants has extensive repair experience, making us the ideal partner for any remedial waterproofing needs.

Our Knowledge

We offer a range of services, including basement waterproofing, roof waterproofing, and leaking balcony repairs, providing a comprehensive solution for any waterproofing issues. Our team of experts can accurately diagnose the issue and identify the point of entry to prevent further water damage. We provide detailed specifications for repairs, ensuring that the underlying cause of the waterproofing issue is addressed.

Our Experts

At MJ Engineering, we understand that every building has unique waterproofing needs. That’s why our team of certified waterproofing consultants provides tailored solutions to meet the specific needs of your property. We also use high-quality materials and products in our remedial waterproofing services, ensuring that our repairs are long-lasting and effective.

The MJ Engineering Projects Experience


Over 20 Years Experience

Our team of specialist remedial engineers who are also registered design practitioners have over 20 years of experience and would be able to assist with any issues.


Leading Industry Expertise

Our team focuses only in remedial engineering meaning that you can be rest assured with our specialist knowledge and expertise.


Over 1,000 Buildings

With over 1,000 buildings inspected, our team of engineers are able to troubleshoot any concern that may be encountered.

FAQs About Remedial Waterproofing Repair

Waterproofing systems can fail for several reasons, including:

  1. Poor Installation: Inadequate installation is one of the most common reasons for waterproofing failure. If the waterproofing system is not installed correctly, it may not withstand water pressure or other environmental factors. Poor installation can include incorrectly applying waterproofing products, using inferior quality materials, and not following the manufacturer’s installation instructions.
  2. Wear and Tear: Over time, even the most robust waterproofing systems can become damaged or worn out, leaving them vulnerable to leaks and other problems. Exposure to UV rays, changes in temperature and humidity, and mechanical damage can all contribute to wear and tear. Chemical exposure, such as in cleaning products or nearby construction, can damage waterproofing systems.
  3. Structural Damage: Structural damage to a building can also lead to waterproofing failure. If the foundation of a building shifts or settles, it can cause cracks in the walls or floors, leading to water intrusion. Similarly, if the building settles unevenly, it can cause the waterproofing system to stretch or tear, leading to leaks.
  4. Environmental Factors: Extreme weather conditions, such as heavy rain or flooding, can also cause waterproofing systems to fail. When a building is exposed to prolonged periods of heavy rain or flooding, water can seep into the structure and compromise the waterproofing system.

The impact of waterproofing failure can be severe and may include the following:

  1. Structural Damage: Water intrusion can cause significant structural damage to a building, leading to costly repairs. Over time, water can weaken the structure of a building and lead to the rotting, rusting, or warping of building materials. This can compromise the integrity of the building and make it unsafe to occupy.
  2. Health Hazards: Water intrusion can also lead to mould growth, which can be hazardous to human health. Mould can cause respiratory problems, allergic reactions, and other health issues. Additionally, water damage can create an environment that promotes the growth of bacteria and other microorganisms, harming human health.
  3. Cosmetically Unappealing: In addition to structural and health hazards, water intrusion can cause cosmetic damage, such as peeling paint or wallpaper, which can be unsightly. This can negatively impact the value of the building and create a negative impression on visitors or customers.

Regular waterproofing inspections and maintenance can help prevent more significant problems from occurring down the line. By detecting and addressing minor issues early on, building owners can avoid more extensive and costly repairs later.

It is important to consider local codes of compliance when undertaking waterproofing repairs. In Australia, waterproofing repairs must comply with the Building Code of Australia (BCA). The BCA outlines the requirements for waterproofing in various buildings, including residential and commercial buildings. At MJ Engineering, we can assist with the tender process to find a suitable contractor who adheres to all relevant codes and regulations for waterproofing repairs.

Insurance statistics show the highest number of waterproofing failures stem from issues with the balconies, terraces, rooftops in high rise dwellings and commercial buildings. There are a number of issues that may be the cause, including;
  1. Use of cheap/inferior materials to save money.
  2. Railing post and penetrations causing water ingress due to poor preparation and detailing.
  3. Failure to pick up building defects through the building surveyors’ inspection process.
  4. Inadequately waterproof detailing from balcony to wall interfaces
  5. Poor design criteria within many buildings which lack appreciation of water control, leading to costly damage that can be difficult to properly remedy.

The simple fact is that waterproofing membranes are only as good as the surface to which they have been applied or installed. The single biggest cause of waterproofing failures stems from poor workmanship, making it more crucial than ever to entrust your waterproofing needs to reliable and proven builders. It’s important to remember the failure of a waterproofing membrane or device can occur at any stage of the life of a building – it may fail straight away or after 1, 5, 12 or 20 years.

Simply put, water ingress is when water from outside gets into a building. It can happen in many different ways and for many different reasons in a building or property. 

To determine the responsibility of water damage, it is important to find out where the water damage or water leak started.

Common strata property is everything outside of the individual units or apartments. This includes the hallways, lobby, lifts, stairs, car parks, gardens, gyms, swimming pools, and so on. It also includes the walls that connect the units and flats, as well as any other space that isn’t on the building plan for a specific unit. If water damage to a strata property starts here, it usually could be claimed that the owners corporation is responsible for the water damage.

On the other hand, a unit or apartment is a private space in the house. According to NSW Fair Trading, “the basic rule is that everything inside the airspace of the unit, including all internal walls, fixtures, kitchen, bathroom and paint on the walls, is usually the lot and, therefore, the responsibility of the unit/apartment owner.” If the water damage comes from inside a unit or flat, the owner of the unit/apartment is usually responsible for fixing it.

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