MJ Engineering Projects provides waterproofing services across Sydney for strata, commercial and residential buildings. We are remedial waterproofing consultants, not applicators. We diagnose why water is getting in, design a repair that meets the NCC, AS 3740 and AS 4654, then tender and superintend the works so the fix is done the first time properly.
Most waterproofing failures are not membrane problems. There are design and workmanship problems that show up in the membrane. A leaking balcony might trace back to falls that pond water at the door threshold, a missing flashing, blocked scuppers or a slab crack two rooms away. Patch the wet spot, and the water finds the next weak point.
That is why our waterproofing services start with diagnosis. As remedial engineers, we trace the water to its entry point, work out why the original system failed, and design a repair that deals with the cause. The applicator then works to our specification, and we check their work against it. The person verifying the repair is never the person being paid to do it.
In NSW, there is also a compliance reason. Under the Design and Building Practitioners Act 2020, waterproofing designs for class 2 buildings must be prepared by a registered design practitioner. MJ Engineering Projects holds that registration (DEP0002740), so our documentation stands up when Fair Trading, a certifier or a tribunal looks at it.
Every engagement follows the same four stages. You can bring us in for a single stage or the whole process.
An engineer inspects the area where water ingress is reported, plus the areas adjacent and below, using moisture mapping and diagnostic testing where needed. You receive a written report identifying the cause of the failure and the recommended rectification pathway. To book an inspection, call 1800 953 935 or email info@mjengineeringprojects.com.au.
We prepare a rectification design and technical specification covering methodology, membranes, flashings, falls and drainage, written so any competent contractor can price and build from it. Designs comply with the NCC weatherproofing provisions and AS 4654 for external above-ground membranes. See our technical specification service page for how these documents are structured.
We run a competitive tender with experienced Sydney remedial contractors, then assess the bids on methodology, track record and price, not price alone. You get a clear recommendation and a like-for-like comparison. More detail is on our tender processing page.
We superintend the works from our Artarmon office across Greater Sydney: The project closes with documentation handed over to whoever manages the asset, from owners corporation and asset managers to individual owners. Our superintendent duties page explains this role.
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 our waterproofing consultants fixing the current system rather than replacing it entirely. Repairs include patching cracks or holes, sealing gaps and re-applying waterproofing products.
A full system replacement may be necessary if the existing waterproofing system is beyond repair or if a partial replacement would not be effective. While this can be costly, ensuring the building is adequately protected from water intrusion is often necessary.
We provide building waterproofing services for every part of the envelope and wet areas, including:
The most common failure point in Sydney strata buildings, typically at door thresholds, balustrade fixings, membrane terminations, penetrations, drainage outlets and movement joints
Including membrane overlays, flashings, drainage upgrades and detailing around plant and solar penetrations
Where groundwater pressure calls for injection works, joint sealing and drainage improvements
Which stain facades and leak into interiors when drainage and membranes fail together
Where inadequate falls and poor junction detailing cause swollen skirtings and loose tiles
Where seepage through mortar joints and wall interfaces causes persistent dampness
Assess water ingress through block walls and related waterproofing defects to help identify the cause and required rectification.
Investigate courtyard waterproofing defects, drainage issues and water ingress affecting surrounding or underlying building elements.
Assess planter box waterproofing and drainage defects contributing to moisture ingress in adjoining slabs, walls or finishes.
Water ingress rarely travels alone. Where a failed membrane has already caused concrete spalling or magnesite damage, we scope both repairs in one project through our remedial building services page.
It depends on what has failed and how far the water has travelled. Repairing an isolated membrane defect costs a fraction of a full balcony strip-and-relay across a strata block, which is exactly why the inspection comes first: it tells you whether a targeted repair will hold or whether patching would be money wasted.
Our fees are quoted as a fixed fee proposal before any work starts, broken down by stage, so an owners corporation can approve the inspection and report first and decide on design, tender and superintendence once the findings are in.
Here are some key results we’ve delivered for Remedial Waterproofing.
With more than eighteen years of proven experience in remedial engineering, our firm has built a strong reputation for delivering reliable and long-lasting results. As registered design practitioners, we specialise in repairing building defects across a wide range of projects, from heritage façades that require delicate restoration to modern high-rise towers that demand technical precision.
Our structured project management approach, combined with thorough quality control processes, ensures every repair is handled with efficiency and care. We focus on minimising disruption, controlling costs and tailoring repair strategies to meet the unique requirements of each client.
This commitment to detail and excellence enables us to consistently provide durable, value-driven solutions that stand the test of time.
Our engineers bring extensive expertise in remedial engineering, supported by years of specialised experience and a detailed understanding of industry standards. We take pride in delivering tailored remediation strategies that address both visible and hidden defects across a wide range of building types.
By staying informed of changing regulations and compliance requirements, our team ensures every project achieves technical excellence and long-term durability. We also place a strong emphasis on sustainability, applying environmentally responsible practices and innovative methods wherever possible.
From diagnosing complex issues to implementing cost-effective repair programs, we are committed to providing clients with outcomes that are reliable, compliant and built for the future.
We have successfully completed inspections and remedial work on more than one thousand residential, commercial and industrial buildings across Sydney. This extensive experience allows us to identify and resolve issues with accuracy, from water ingress and façade deterioration to concrete spalling and structural concerns.
Each project benefits from a customised repair strategy designed to achieve durability, compliance and lasting performance. Our large and diverse portfolio equips us to anticipate challenges, optimise resources and streamline delivery to minimise site disruption.
With this proven track record, we are confident in managing projects of any scale or complexity, delivering solutions that are efficient, cost-effective and built to endure.
Our credentials reflect a strong commitment to professional standards, compliance, and continuous improvement. We maintain active involvement with leading industry bodies and hold recognized certifications and registrations, including ISO Certifications and NSW regulatory registrations.
View our capability statement for a full overview of our services, credentials and project experience.
Client: Owners Corporation
Remedial works at Little Street, a three-storey strata complex of eight apartments in Lane Cove, have repaired concrete spalling, renewed balcony finishes and introduced...
Client: Owners Corporation
Remedial works at Milsons Point have stopped persistent water ingress, repaired concrete damage and delivered a modern balcony enclosure that satisfies the Design and...
Client: Owners Corporation
Remedial works at Kensington tackled persistent balcony leaks, blocked scuppers and early concrete decay that were staining interiors and increasing insurance risk. MJ Engineering...
Key Concerns and Frequently Asked Questions About Remedial Waterproofing Repair in Australia
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No, and that is deliberate. We are waterproofing consultants: we diagnose the failure, design the repair, tender it to experienced Sydney waterproofers and superintend the work. Keeping the engineer separate from the applicator means the person checking the membrane is not the person who installed it.
A membrane is only as good as the surface and detailing beneath it. The most common causes we find are ponding from inadequate falls, unsealed balustrade fixings, failed door threshold details and blocked scuppers. Poor workmanship is the single biggest cause of failure, which is why age alone tells you little. An inspection identifies which of these applies to your balcony.
It depends on where the water started. Under NSW strata rules, common property, including the external envelope and the waterproofing membranes protecting it, is generally the owners corporation’s responsibility, while everything inside a lot’s airspace is generally the owner’s. Our reports identify the entry point, which usually settles the question.
For class 2 buildings (apartments), yes. The Design and Building Practitioners Act 2020 requires regulated designs, including waterproofing, to be prepared and declared by a registered design practitioner. MJ Engineering Projects holds registration DEP0002740, which you can verify on the NSW Fair Trading register.
Localised repair can work where the failure is isolated, the substrate and falls are sound, and the existing system can be identified. In practice, membranes usually fail at terminations, junctions and outlets rather than across the field, so patching where the water appears often treats the symptom rather than the cause.
Waterproofing to a Class 2 building also requires a declared regulated design before work starts, however small the scope. That design must detail how the repair ties into the existing system, which is difficult where the existing membrane cannot be verified.
Our investigation determines the failure mechanism, the extent of the affected area and the condition of the substrate, and identifies the appropriate remedial approach.
We schedule inspections from our Artarmon office across Greater Sydney. Call 1800 953 935 with the building address and a description of the leak, and we will confirm an inspection date and a fixed fee for the report.
Our designs are documented to the NCC and AS 4654, prepared under our design practitioner registration, and the completed works are flood-tested and certified. That paper trail is exactly what buyers, certifiers, and tribunals ask for, and it is the difference between a repair and a defensible repair.
Get in touch with MJ Engineering Projects on 1800 953 935, email info@mjengineeringprojects.com.au, or visit us at Suite 3, 401 Pacific Highway, Artarmon NSW 2064 for waterproofing services across Sydney.
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