Leaky Building Remediation at XXX Broadway, Newmarket

In the heart of Newmarket, Auckland, XXX Broadway stands as one of the suburb’s most prominent commercial office buildings. Known for housing a mix of law firms, consultancies, and other professional tenants, the building had, in recent years, begun to show signs of age—not in its aesthetic, but in its weathertightness. As water staining, warped finishes, and unexplained leaks began to affect multiple levels, it became clear that the property was suffering from the all-too-common issue of being a leaky building.

The Challenge: Widespread Water Ingress Affecting Commercial Tenancies

The Body Corporate responsible for XXX Broadway approached Aamsko to provide a forensic diagnosis and design a lasting solution. Our investigations confirmed what tenants had feared: the building envelope was no longer keeping the weather out. Water ingress was affecting multiple levels—most notably Levels 3 and 4—leading to mould growth, stained ceiling tiles, and rotting timber framing. Leaks appeared intermittently, often during wind-driven rain, making them hard to trace and all the more damaging.

What made this case particularly concerning was the pattern of damage. Water was not simply entering at a single point and affecting the immediate area—it was tracking down from higher levels, concealed behind cladding and structural framing, before finally manifesting inside tenancies. The longer it continued, the more costly the outcome would be. The Body Corporate rightly recognised that patch repairs were no longer appropriate, and a full-scale weathertightness remediation strategy was required.

Initial Findings: A Classic Case of Leaky Building Syndrome

Aamsko’s building surveyors undertook a comprehensive assessment of the structure. This included physical inspections, thermal imaging, invasive moisture testing, and AAMA 511 spray testing—a forensic diagnostic standard that recreates real-world weather conditions in controlled ways to observe how water interacts with building assemblies.

The testing confirmed multiple points of failure:

On the northern and western elevations of the building, large aluminium-framed windows spanning multiple levels had become the primary pathway for water ingress. Over time, the jamb flashings had deteriorated, allowing moisture to enter and travel unseen behind the Eterpan fibre cement cladding. From there, water tracked down through the timber framing, eventually affecting the lower levels. On the eastern side, the problem presented differently but was no less serious—head flashings had been inadequately designed and poorly installed. Water collected at these junctions and seeped through cladding interfaces that lacked effective jointing. In a bid to manage the leaks, makeshift drainage holes had been drilled into the joinery, but these had only worsened the situation by creating additional failure points.

Internally, the damage was undeniable. Tenancies on Level 3 (Focus Law) and Level 4 (Prudentia Law) displayed all the classic symptoms of chronic moisture exposure. Framing was decaying, linings were stained, and some of the concrete beams showed signs of carbonation from prolonged damp conditions. Even the fire escape stairwell and toilet areas were affected, with visible mould, standing water on slab floors, and cracking to both finishes and structural elements. This was a textbook example of a leaky building—but what made the situation especially complex was the fact that XXX Broadway is a high-profile, multi-storey commercial building, fully tenanted and operating in the heart of Newmarket. Any remediation would need to be robust, precisely detailed, and sensitive to the practicalities of keeping the building functional during works.

With the sources of water ingress clearly identified, Aamsko progressed to the next stage—developing a comprehensive, practical leaky building remediation design. Our solution needed to rectify the current issues while preventing future failures, and it had to be carried out in accordance with modern weathertightness principles and performance-based engineering. Our remediation design was therefore structured into three key packages of work. The first addressed the northern and western elevations, where the most severe damage had occurred. The multi-storey spandrel windows on these façades, once a striking architectural feature, had become the main contributors to internal moisture damage. We specified a detailed repair solution involving the installation of custom-fabricated aluminium jamb flashings to replace the failed junctions. These were supported with high-performance sealants and flexible waterproofing tapes to ensure long-term durability. The aim was to stop water at its entry point, manage any incidental ingress, and protect the internal wall assembly from further exposure.

We specified the following solution:

• Installation of custom-fabricated aluminium jamb flashings over all vertical junctions, designed to deflect water away from critical interfaces.
• SikaHyflex®-250 Facade and Sika® SealTape B were used to create high-movement, long-life waterproof seals between the joinery and cladding.
• Tank-It Liquid Flashing was applied to window stools and sills, forming a seamless waterproof barrier beneath the new flashings.
• Backing rod and joint sealant replacement to eliminate degraded silicone work that had failed over time

Three-dimensional drawing of specified retrofit aluminium jamb flashing remedial solution. Drawing created by Aamsko. Each flashing system included drip edges and flexible interfaces, ensuring water would not pool or enter the wall cavity, even under wind pressure.

2. Eastern Elevation Remediation

On the building’s eastern elevation, the problem was different but no less serious. Here, water was entering at the joinery head, bypassing cladding and draining back into the wall assembly. To resolve this, Aamsko designed a retrofit flashing system that included:

• An overflashing pressure bar system, mechanically fixed over the existing head flashings to create a sealed and compressive barrier.
• Removal and replacement of all external sealant joints, using high-performance façade sealants with movement capability.
• Flexible waterproofing using SealTape B, applied to all vertical and horizontal junctions to protect against thermal expansion and contraction stresses.

This solution was less intrusive than a full window replacement yet achieved the necessary waterproofing performance by correcting the key interface details.

3. Building-Wide Elastomeric Coating System

A critical part of our remediation design was the specification of a high-performance elastomeric coating system to be applied to the entire building envelope. No matter how well localised repairs are done, they cannot be fully effective without treating the cladding as a complete system.

Our elastomeric strategy included:

• Crack repair using Sikaflex® AT Facade and backing rod for all cracks over 5mm, plus detail repair at cladding joints.
• Application of two full coats of Wattyl GranoShield Matt, a flexible, breathable, and UV-resistant coating that bridges hairline cracks and prevents future ingress.
• Substrate preparation using Granoprime, and tape-reinforced joints using Sika® SealTape B to allow for thermal movement.

This waterproof membrane acts as a final line of defence—one that can expand, contract, and flex with the building without compromising integrity.

Specification Integrity and Construction Contracting

With the remediation design completed, Aamsko provided a full Statement of Work supported by accurate measurements and pricing estimates using QV CostBuilder. To protect both budget and workmanship quality, we proposed managing the project under the NEC3 construction contract format. This ensures clarity around contractor obligations, timing, performance requirements, and dispute resolution. The Body Corporate could proceed either by engaging Aamsko’s preferred contractor or running a competitive tender process managed entirely by our team. In either case, our involvement ensures compliance with the remediation design and attention to build quality—critical factors in leaky building repair.

A Collaborative, Transparent Path Forward

The success of any weathertightness remediation project lies not only in the design but also in the execution. At XXX Broadway, we recognised that every flashing, sealant joint, and coating application had to be completed with care and precision. That’s why Aamsko insisted on retaining project oversight, providing not just technical drawings, but also installation guides, sequencing plans, and material specifications for every part of the building. Our commitment to transparency extended to our project management systems, which include dedicated bank accounts for trust-held funds, and real-time reporting to the Body Corporate.

The Outcome

As the project moves forward into delivery, the Body Corporate can have confidence that the remediation approach is not just a temporary fix—but a long-term investment in asset resilience. By treating the building as a complete system and combining our legal, architectural, and building science expertise, Aamsko has delivered a solution that not only resolves current issues but protects the value of the property for decades to come.

Get Help with Your Leaky Building Today

Weathertightness remediation is never a one-size-fits-all job. Every building is unique, and every failure tells a story. At Aamsko, we believe in getting to the bottom of the issue—then designing a fix that actually works.

Whether you’re a Body Corporate, building manager, or property owner, we’re here to help you take control of your weathertightness concerns before they spiral into major costs.

📞 Contact us today to discuss a site-specific solution for your commercial building.

Aamsko New Zealand – Experts in Leaky Building Remediation Design, Contract Management, and Weathertightness Consultancy.