Every strata manager has had the email. An owner has noticed a crack in the external brickwork, they have sent a photo, and they want to know whether the building is falling down.
Most of the time it is not. But “most of the time” is not an answer you can put in front of a committee, and the gap between a cosmetic mortar issue and a genuine structural problem is the difference between a maintenance line item and a special levy.
Here is how to think about it.
The problem: the visible crack is rarely the actual defect
Brickwork tells you something is wrong long before it tells you what is wrong. By the time a crack is visible from the courtyard, the underlying cause has usually been at work for years.
The three causes we see most often across Sydney strata buildings are:
Mortar deterioration. The mortar between bricks is doing two jobs at once. It holds the wall together and it seals it against water. Weather exposure and age break it down, and once it starts crumbling, the wall loses both strength and its weather barrier at the same time.
Water getting in. Failed mortar joints let moisture into the wall. That moisture carries salts through the brickwork, which is what produces the white powdery efflorescence owners often report. Left alone, it degrades the bricks themselves and shows up as damp patches on interior walls. In cavity wall construction, water that gets past the outer leaf is supposed to be managed and drained out, which is why a brickwork problem and a cavity flashing problem often turn out to be the same problem seen from two directions.
Corroded brick ties. These are the metal connections holding the outer leaf of a cavity wall to the structure behind it. They are invisible from the outside and they corrode quietly. This is the one that matters most, because a wall with failed ties can look almost perfect from the ground.
That last point is why photographs are not a diagnosis. The most serious brickwork defects are the ones with the least dramatic surface presentation.
What actually tells you it is structural
There is a rough hierarchy in what an owner reports, and it is worth knowing where a given complaint sits.
Usually cosmetic: discolouration, faded or mismatched mortar, uneven joint work from a previous repair.
Needs attention, not urgent: hairline cracking in mortar joints, minor crumbling, isolated missing mortar.
Get it inspected: cracks that run diagonally across bricks rather than following the joints, large sections of missing mortar exposing the inner wall, efflorescence, water stains running down the face, damp patches appearing on interior walls.
Get it inspected now: loose bricks that move under hand pressure, and any wall that appears to be bowing or leaning inward or outward. Bowing is the one to escalate immediately, because it points to a connection or stability failure rather than a surface one.
The practical rule: cracks that follow the mortar joints are usually telling you about the mortar. Cracks that run through the bricks are usually telling you about movement.
One pattern worth knowing separately. Horizontal cracking directly above windows and doors often has nothing to do with the brickwork itself. It points to a corroding steel lintel behind it, expanding as it rusts and pushing the masonry apart. If that is what is happening, the brickwork is a symptom and the concrete cancer affecting the embedded steel is the actual defect.
Why waiting costs more
Brickwork defects compound. Failed mortar admits water, water accelerates tie corrosion and salt attack, and salt attack damages the bricks. What starts as a repointing job becomes brick replacement, and what starts as brick replacement becomes structural rectification with engineering involvement.
The earlier brick repairs are undertaken, the less likely extensive damage will be caused. That is not a sales line, it is the physics of the failure mode.
The compliance question for Class 2 buildings
There is a regulatory dimension that catches a lot of owners corporations by surprise.
The Design and Building Practitioners Act 2020 and its Regulation apply to building work on a Class 2 building or a building with a Class 2 part, and that includes rectification work, whether or not building approval was required. If your building is an apartment block, remedial brickwork is not simply a maintenance decision. It carries design and compliance declaration obligations that need to be planned for at the scoping stage, not discovered at the end when a certificate is needed.
There is a narrow exemption for genuine emergency remedial work, where action is required immediately to prevent serious damage or remove a safety risk. It is worth understanding, but it is deliberately narrow. A wall that has been slowly cracking for three years is very unlikely to qualify, and treating a known defect as an emergency to sidestep the process is not a position an owners corporation wants to be in.
The practical takeaway for a strata manager: ask the compliance question at the quoting stage, not after the scaffold is up.
The solution: diagnose before you scope
The mistake we see most often in strata brickwork is scoping the repair from the symptom. An owners corporation gets a quote for repointing, the repointing is done, and two years later the same cracks are back because the movement or the tie corrosion causing them was never addressed.
A proper assessment establishes three things before anyone quotes a method:
- What is failing. Mortar, bricks, ties, lintels, or the structure behind them.
- Why it is failing. Water ingress, salt attack, movement, or age. The cause determines the repair.
- How far it extends. Whether this is a localised area or a wall-wide condition, which is usually the difference between a small job and a capital works item.
Only then does the repair method follow. On BIM’s brickwork jobs that typically means one or more of: brickwork repointing to restore the mortar and the weather seal, brick stitching where cracking needs to be tied across, fretted brickwork replacement where individual bricks have degraded beyond saving, brick pier replacement, brick sealant works, or complete brickwork remediation where the condition is widespread.
Where salt degradation is present, the sequence matters. Affected bricks are removed, the remaining brickwork is treated for the salt, bricks and brick ties are replaced as required, and only then is the wall repointed back to condition. Repointing over an untreated salt problem simply seals the cause in.
What to ask for before you approve a scope
If you are a strata manager putting brickwork to your committee, these are the questions worth asking any contractor:
- What is the diagnosed cause, not just the observed symptom?
- Does the scope address that cause, or only the visible damage?
- Are brick ties being assessed, or assumed to be sound?
- If this is a Class 2 building, what compliance documentation comes with the work?
- What does the contractor provide for tender or committee approval purposes?
A contractor who can answer all five is scoping the building. One who can only answer the first is quoting a photograph.
Talk to BIM Sydney
BIM Sydney is an established remedial building contractor working across Greater Sydney, with over $80 million in completed contracts and more than 1,000 clients. We hold NSW Builder Licence 198846C, are ACRA members, and are ISO certified.
Read more about our brickwork rectification and brick repointing services, or call 02 9938 1740 to arrange a site inspection.
If you are dealing with a related issue on the same building, our concrete spalling repairs and facade restoration teams work across the same elevations, so the whole building envelope can be assessed in one visit.
