What is Concrete Cancer? Signs, Causes and Treatments

Southern Remedial Solutions • November 7, 2023

Are your concrete structures showing signs of wear and tear? If you suspect concrete cancer, it is of absolute importance to act promptly to avoid expensive repairs down the road. Seeking professional concrete repair Sydney services is often the best course of action. However, if you're looking to understand the intricacies of concrete cancer, this comprehensive guide has you covered. Here, we'll delve into the causes of concrete cancer, signs to watch for, and effective methods for remediation and long-term preservation of your valuable concrete assets. Whether you're dealing with an existing issue or seeking preventative measures, this blog will equip you with the knowledge that you need to protect your concrete structures effectively. Continue reading to learn more.

What is concrete cancer?

Concrete cancer, also known as concrete spalling or concrete degradation, is a condition in which concrete structures begin to deteriorate due to the corrosion of the steel reinforcement bars within the concrete slab. It is a progressive and often irreversible problem that can affect the structural integrity of various concrete structures including buildings, bridges, tunnels, and other infrastructure.

concrete spalling

What are the common signs of concrete cancer?

Concrete cancer can occur at any time, so it is advisable to be aware of some potential indicators that your building may be impacted. If you suspect it in a building, it's advisable to seek professional assistance from a structural engineer to diagnose concrete cancer accurately. Some common signs of concrete cancer include:


  • Concrete cracks
  • Crumbling concrete
  • Rust stains on concrete
  • Bubbling concrete render
  • Leaks in overhead concrete surfaces and internal walls
  • Concrete expanding outwards

What causes concrete cancer?

Concrete cancer is mainly caused by the corrosion of steel reinforcement bars in concrete structures. This occurs when water and oxygen come into contact with the embedded steel, leading to rusting and weakening of the metal. Other factors that can lead to concrete deterioration include:

Poorly Poured Substrate

Poorly poured substrate can create vulnerabilities in the concrete structure that, over time, allow water, oxygen, and other corrosive agents to seep in the reinforcing steel. When the steel begins to corrode, it will then start to expand, creating internal pressure that causes the concrete to crack, spall, and disintegrate. To prevent concrete cancer, proper substrate preparation and pouring techniques should be used.

Poor Waterproofing

Poor waterproofing is another major factor that can lead to concrete cancer. When water penetrates the concrete, it can carry harmful substances such as chlorides and carbon dioxide that can corrode the reinforcing steel and cause it to expand. Additionally, the presence of water can increase the pressure on the concrete from within, weakening its structural integrity. Thus, leading to cracks, spalling, and eventual disintegration. Keep in mind that waterproofing should be done properly with the right materials and techniques to prevent water ingress.

Building Defects

While building defects themselves may not directly cause concrete cancer, they can create conditions that may contribute to the corrosion process. Defects that are related to drainage systems, concrete cracks, and gaps can lead to the accumulation of water in the surrounding concrete. As a result, this creates an environment that is ideal for the growth of bacteria and fungi, leading to further corrosion. By taking measures to repair these defects as soon as possible, property owners can ensure that their properties are better protected against concrete cancer.

Poor Quality Concrete

Poor-quality concrete can compromise the protective properties of the concrete, making the steel reinforcement more susceptible to corrosion. Once corrosion of the steel begins, it can lead to the expansion of the rebar and the development of cracks and spalling in the concrete. To prevent concrete cancer, it's important that you use high-quality concrete materials to guarantee proper compaction and provide adequate concrete cover for the rebar to protect against corrosion.

Insufficient Concrete Cover

Insufficient concrete cover refers to the inadequate thickness of the concrete layer that surrounds the steel reinforcement (rebar) within a concrete structure. If the cover is too thin, it can leave the steel exposed to environmental factors and cause corrosion. This can lead to concrete cancer and destabilisation of the structure. In this case, the building performance for earthquake resilience can be drastically reduced. To prevent this, make sure you use adequate amounts of high-quality material to guarantee a sufficient concrete cover for your rebar.

Ground Movement

Ground movement can cause concrete spalling through a phenomenon called 'subsidence'. When the ground beneath a concrete structure shifts or settles unevenly, it can create added pressure and stress on the concrete. This can lead to the development of cracks in the concrete, which, over time, can allow moisture and aggressive chemicals to penetrate the structure. As a result, the concrete may start to deteriorate, leading to concrete cancer. Proper construction techniques, regular inspections, and addressing subsidence issues promptly can help prevent this form of concrete deterioration.

How do you repair concrete cancer?

Depending on the extent of damage and specific circumstances, concrete cancer repairs may involve the following:

Onsite Inspection

Start by assessing the extent of the damage. Look for signs of concrete cancer, such as rust stains, cracks, spalling, and exposed reinforcement bars.

Removal of Affected Concrete

Remove the damaged or corroded concrete, making sure that all rust and deteriorated material is completely removed. To further protect the rebar, use a corrosion inhibitor or anti-rust treatment.

concrete wall inspection

Reinstatement of Concrete

After treating the reinforcement bars, reinstate the removed concrete using a high-strength polymer modified material. Typically, a polymer-modified repair system is often used because of their durability and bonding properties. Through this system, damaged concrete surfaces, especially those with corroded reinforcing bars can be repaired. They work by enhancing adhesion, improving structural integrity, and increasing resistance to further deterioration. By bridging cracks, sealing damaged areas, and preventing further corrosion, polymer modified repair system can effectively fix concrete cancer and restore the structure's integrity.

Application of Protective Coatings

To prevent future moisture ingress and corrosion, anti-carbonation coatings or waterproofing solutions can be applied to the repaired concrete surface. Anti-carbonation protective coatings are specialised coatings that are applied to concrete structures, such as buildings, bridges, and parking structures, to protect them from carbonation.


When concrete carbonation occurs, carbon dioxide from the air penetrates concrete and reacts with the calcium hydroxide in the cement to form calcium carbonate. While this may sound harmless, carbonation can lead to corrosion. With an anti carbonation protective coating, the concrete can be protected from further permeation of carbon dioxide, preventing corrosion and preserving its strength and durability.

Regular Maintenance

After repair, it's essential to perform regular inspections and maintenance to detect and address any issues promptly, and mainly to prevent the recurrence of concrete cancer. Regular maintenance can also help to identify defects and weaknesses in the concrete before they become serious.

Takeaway

Understanding what concrete cancer is and how to address it is crucial for the longevity and safety of your structures. By recognising the signs early, seeking professional diagnosis, and implementing appropriate repair methods, you can extend the life of these structures and prevent further deterioration.


At Southern Remedial Solutions, we are concrete remediation specialists servicing Wollongong and the Illawarra, Sydney, South Coast & Southern Highlands. Using industry-leading technologies, we can provide concrete repair solutions to enhance the strength and durability of your structure. Whether you need concrete cancer treatment, concrete restoration and cleanup, or concrete leak repair, our concrete specialists are well-equipped to quickly diagnose, cure, and provide enduring protection for your concrete to prevent further damage. Contact us today to get a free estimate.

By Zeke Stankov October 16, 2025
We all know markets shift. But far more damage to your returns can come from hidden defects in the building itself. Even a premium location loses value when tenants complain of leaks, cracks, or wiring faults. Repair bills pile up. Spot a problem before you purchase, and you may avoid five- or six‑figure remediation work down the track. Concrete Remediation Red Flags The bones of a building matter most. Structural defects threaten safety and long-term viability. Watch for early signs. • Cracks in walls, foundations, or ceilings Fine hairline cracks are normal. Wide, diagonal cracks that widen at corners of openings (doors/windows) are serious. In concrete slabs or beams, cracks may signal reinforcement corrosion or movement. A remedial building specialist can inject cracks using epoxy or polyurethane crack injection to restore strength. • Uneven floors or doors that won’t close properly If a door drags or won’t latch, or floors slope uncomfortably, you may be seeing foundation settlement or shifting slabs. These defects are not cosmetic — they often hide deeper movement or void formation under slabs. • Sagging rooflines or visible structural movement If the roof ridge sags, or internal columns or beams are visibly displaced, that is a serious red flag. Look up the underside of beams, roof timbers or concrete girders may show shifting or cracks. A building inspector should check for deflection or creeping movement. Water Damage Warning Signs Water is a silent destroyer. Moisture issues often go unnoticed until major damage flares. Be alert for clues. • Stains on walls or ceilings Brown, yellow or gray stains are often tell‑tale signs of leakage. If stains reappear after rain, the waterproofing is likely compromised. • Musty odors indicating mold A persistent earthy, damp smell suggests mould growth behind walls or under flooring. That signals ongoing moisture ingress. • Poor drainage around the property Soil that slopes toward the building, blocked downpipes, or saturated ground next to foundations increase the risk of water penetrating the structure. • Faulty waterproofing in wet areas Bathrooms, balconies, terraces and planter boxes are frequent leak zones. Cracked tiles or blisters in membranes suggest waterproofing failure. Moisture can reach the concrete shell and cause spalling or corrosion over time — a concrete remediation expert must address such damage. Explore hidden problems in old homes that require remedial building work. Electrical and Plumbing Issues Even if the concrete shell is sound, poor services can ruin value, safety and tenant comfort. Plausible red flags exist. • Outdated wiring systems Wiring over 30–40 years old, knob‑and‑tube or aluminium wiring, or fuse boards with limited capacity are all risky. These may not meet modern codes, and insurers may balk. • Frequent power trips or flickering lights If light switches flicker or circuits trip under light load, you may have overloaded circuits or weak connections. • Poor water pressure or recurring blockages If several fixtures suffer low pressure, or blockages are frequent, the plumbing network or drainage might be undersized, corroded or poorly installed. • Signs of previous DIY electrical work Nonstandard junction boxes, loose conduit, exposed wiring or non-code splice work point to bad repair history. These raise red flags about safety and insurance compliance. External Building Envelope Problems The external façade is your first barrier to weather and moisture. If it fails, everything behind it is at risk. • Deteriorating render or cladding Render cracks, delamination, broken joint seals, crumbling corners — these show the shell is failing. Water may be entering behind the façade. • Missing or damaged roof tiles A roof in poor condition permits rain driving into rafters and ceiling spaces. Even small gaps can allow moisture ingress. • Blocked or damaged gutters Overflowing or sagging gutters push water down walls or into foundations. That tests waterproofing and concrete joints. • Window and door seal failures Failing seals or gaskets let water, drafts or moisture in. Re-sealing might be simple, but if the structural aluminium or framing is corroded, deeper repair is needed. How injections help restore historical buildings . What to Do Before Purchasing You can’t eliminate risk. But you can take steps to manage and anticipate it. • Engage qualified building inspectors Hire a licensed building inspector experienced in remedial and structural defects. They can flag when concrete remediation is needed or a crack needs injection from the outset. • Review strata reports for defect history In apartment or strata assets, the strata defect report or maintenance ledger may already record recurring defects, structural issues, or past repair budgets. Hidden liabilities lurk there. • Budget for potential remedial work Assume some defects will surface. Set aside 5–10 % of purchase cost for remediation. That might include concrete remediation, structural fixes or waterproofing replacement. • Consider walking away from problem properties If the defects are systemic, or remediation costs are uncertain or unaffordable, be ready to back out. Don’t justify a bad deal with optimistic assumptions. Structural cracks, water damage, faulty services and envelope failures are red flags no investor can ignore. A property may seem sound, but latent defects erode returns and deliver expensive surprises. Good inspections, proper budgeting, and cautious decision‑making work as your insurance against ruinous defect costs. Only a professional can reliably assess the need for concrete remediation, or whether a crack requires polyurethane crack injection or more advanced repair. At Southern Remedial Solutions, we specialise in concrete repair, waterproofing and remedial building work across NSW. Don’t buy blindly. Engage us early to inspect major assets, assess hidden defects, and help you negotiate with confidence. Contact Southern Remedial today for a full building defect audit.
By Zeke Stankov October 8, 2025
Australia is seeing more frequent and intense storms. From damaging hail in Queensland to coastal deluges in NSW—weather extremes are no longer rare. Recent Bureau of Meteorology data show an uptick in storms that cause large property damage. Waiting for damage to happen is costly. Proactive building assessment beats reactive repairs. And catching issues early saves money, protects safety and reduces stress. Key Storm Vulnerabilities in Buildings Storms stress every part of a building. Some weak points take damage first. Knowing where those are, helps you act ahead of time. • Roofing systems Roofs take a beating. Strong winds may lift or break tiles. Gutters can clog or detach. Flashing (the metal strips around joins and chimneys) can be torn or shifted. Any of these allow wind or water in. • Windows and doors Windows and doors must seal tightly. If seals fail, water penetrates. Frames may warp in strong wind, or hinges and locks weaken. In many buildings, windows don’t have storm-rated coverings or shutters. • External walls Walls are more than an aesthetic shell—they keep storms out. Cracks in masonry or render let water seep in. Cladding that’s improperly fixed or deteriorated can peel off or allow water entry. Also, concrete spalling (when concrete surface flakes or chips away) exposes steel reinforcements to water, which worsens the damage. • Drainage systems If water can’t run away fast enough, it builds up. Roof water, run-off from hard surfaces, clogged downpipes, or blocked stormwater drains all cause pooling. This leads to flooding, erosion around foundations, leaks, or undermining of structural soil support. What is magnesite removal – understanding what it is and when you should get it. Essential Pre‑Storm Preparations You want your building to face a storm without surprises. Some things you can do yourself. Others need expert hands. Start now, well before heavy rain and wind hit. Immediate actions include - 1. Clean gutters, downspouts and stormwater drains. Remove leaves, debris and obstructions. 2. Secure or remove loose objects around the property—outside furniture, signs, or loose roofing elements. 3. Check seals around windows, doors and roof penetrations. Replace or repair worn sealing strips, flashing, and weather-strips. DIY inspections work for visible damage and maintenance. But call in concrete repair contractors or remedial building specialists when you notice structural cracks; when concrete spalling or concrete cancer appears; or when complex waterproofing, roofing, or structural reinforcement seems needed. Experts can uncover hidden damage. They have tools to test moisture, strength, reinforcement corrosion, etc. Warning Signs Your Concrete is Spalling Storm damage shows itself early if you know what to look for. Don’t wait for a big crisis. Watch for small failures—they’re often the first sign. • Water stains or dampness Stained ceilings, walls, or patches of mould inside are bad news. They mean water is getting through somewhere. Could be roof, wall, or even ground water. • Visible cracks in walls or foundations Hairline cracks may widen under pressure. Cracks in foundations or load‑bearing walls can signal serious structural issues. Early repair is cheaper and safer. • Loose or missing roof materials Tiles shifted, metal roof sheets loose, broken flashings, missing ridge caps—all invite water and wind damage. • Poor drainage around the building Pooling water near foundations. Guttering overflowing. Soft soil around walls. All raise risk of water ingress, erosion, and foundation movement. Understanding signs that show your building’s concrete needs repair . Professional Storm‑Proofing Services Some work requires specialist tools, knowledge and techniques. Professional help makes a difference. It ensures your building not only weathers one storm but many. • Structural assessments and waterproofing Experts can test structural strength, check reinforcement corrosion, assess moisture absorption. They can apply waterproofing membranes, sealants, coatings, moisture barriers. This includes dealing with concrete spalling or concrete cancer to prevent deterioration of key load‑bearing elements. • Roof repairs and reinforcement Repair or replace damaged roofing tiles, metal sheeting, ridge caps and flashings. Reinforce roof trusses if needed. Ensure gutters and downpipes are securely fixed and correctly sized. • Window and door upgrades Install storm‑rated windows, reinforced frames, proper sealing. Add shutters or storm panels. Replace damaged seals and tracks. • Drainage improvements Ensure gutters, downpipes and stormwater drains are clean, properly pitched, sized. Redirect soil slope away from foundations. Install or maintain surface and subsurface drains where needed. The Cost of Being Unprepared Skipping preparation seems cheaper—until something breaks. The financial, safety, and operational costs of storm damage add up fast. • Emergency repair costs vs preventive maintenance Emergency storm repairs can cost many times more. Fixing a collapsed roof or flooded basement eats into budgets. Regular maintenance and repairs—such as work by concrete repair contractors—cost far less over time. • Insurance complications and claim rejections Insurers expect maintenance. If you can’t prove you regularly looked after your building, claims may be denied. Unreported damage (like ongoing spalling or unseen leaks) will weaken your case. • Business disruption and safety risks Storm damage can shut down operations. Employees or residents may be unsafe. Slip or fall hazards, structural collapse risks, mould illness all come from deferred maintenance. Contact Concrete Repair Contractors Your building can withstand the storms ahead—but only if you act now. By spotting weaknesses in your roof, windows, walls or drainage; by taking preparatory steps; and by hiring the right professionals, you protect your structure, your people, and your wallet. If you want to know whether your building is storm‑ready, Southern Remedial Solutions can help. We offer inspections, concrete spalling and cancer repair, waterproofing, roof and window upgrades, and drainage services to make buildings safer and more resilient. Contact us today at 0431 070 373 for a no‑obligation on‑site assessment. Let’s get ahead of the next storm—before it hits.
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Concrete cancer happens when steel inside the concrete rusts. This rust pushes outward and cracks the surface. Eventually, pieces flake or fall off. But why is it called cancer? Like cancer in living tissue, this damage starts quietly and grows. It spreads under the surface and eats away strength, layer by layer, from within. Visual signs include keeping an eye out for rust-coloured stains, widening cracks, and chunks of concrete falling away. These are clear signs of trouble that just won’t wait. What Causes Concrete Cancer? Concrete cancer doesn’t appear from nothing. It often starts small. But over time, it eats away at your structure. Water penetration through poor waterproofing Rain or groundwater finds weak spots. If waterproofing fails, water seeps in. It reaches the steel inside. Over time, it causes rust and break‑down. Salt exposure (coastal properties) In coastal areas, airborne salt can reach your structure. Salt speeds up steel corrosion. It really raises the risk for concrete cancer. Poor construction practices Even new buildings suffer if construction cuts corners. Too little concrete cover, low-grade materials, or bad compaction can all make concrete more vulnerable. Age and wear of buildings All buildings age. Over time, concrete wears down. Cracks form, covers thin out, and even minor damage can start a cycle of decay. Understand why water proofing your basement is important. Warning Signs You Can’t Ignore Signs of trouble often start small. You might not notice them right away. But once you see them, act fast. Rust‑coloured stains on walls or ceilings These orange-brown streaks hint that steel inside is rusting. This is concrete cancer in the making. Hairline cracks that grow over time Thin, fine lines may seem minor. But if they widen, deepen, or grow longer, they’re serious. Concrete pieces breaking away If bits of concrete chip or flake off, that’s a clear escape path for rust. It only gets worse from there. White chalky deposits (efflorescence) White, powdery residue usually means water moved through. It often precedes more serious damage. Bulging or bowing concrete surfaces When concrete pushes out or bows, internal pressure builds, and this is rust swelling inside. The Real Cost of Ignoring It Skipping repairs might seem cost‑saving now. But it’s a risky choice. The price comes due—and usually with interest. Structural safety risks Compromised concrete weakens your building. It becomes unsafe—for residents, users, and anyone nearby. Expensive emergency repairs vs. early intervention Calling in help early is usually cheaper. Emergency fixes cost more. They also disrupt life and work more severely. •Property value decline Buyers and insurers spot damage fast. Concrete cancer cuts resale value and could hike insurance costs. • Potential building collapse in severe cases In extreme situations, unchecked decay leads to collapse. That risk is too high to ignore. Explore the role of waterproofing in concrete remediation. How Concrete Repair Contractors Can Help Southern Remedial steps in with focus and care. They don’t just patch the surface. They restore strength and peace of mind. Professional assessment and diagnosis The team starts with a full inspection. We use our skills to identify the problem’s extent. Concrete repair and remediation process We carry out concrete remediation by using industry-leading tech to inject cracks, rebuild damaged areas, and restore strength. Waterproofing solutions After the fix, we will seal surfaces. This guards against future water entry and keeps concrete safe and sound. Prevention strategies for the future We will help you set up regular checks and advise on preventive maintenance. This saves time, money, and risk. Concrete Remediation is The Cure A small check today can spare a big headache tomorrow. And Southern Remedial makes prevention simple. Regular building inspections Inspections spot minor issues before they grow. A quick check can stop concrete cancer before it starts. Proper waterproofing maintenance Keeping waterproofing in good shape keeps water out. And water is the enemy of concrete. Early intervention saves money Fixing small issues is far cheaper than major repairs. You save money, time, and stress. When to call the professionals Contact concrete repair contractors as soon as you spot warning signs. Don’t wait for cracks to grow or fragments to fall. Free inspection offer Southern Remedial often offers a no‑cost initial check. You get peace of mind and an honest plan. Concrete cancer, a result of rusting steel can sneak up on any building. If water, salt, poor build quality, or age let corrosion start, cracks, stains, and crumbling follow. Ignoring it risks safety, value, and cost more in the long run. Southern Remedial steps in with skilled concrete remediation and trusted concrete repair contractors to diagnose, fix, seal, and prevent. A little action today avoids big trouble tomorrow. Contact Southern Remedial for expert assessment. If you notice rust stains or concrete falls away, get help fast. Southern Remedial’s team stands ready to tackle concrete cancer. Call us at 0431 070 373 for more information.
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We hope you enjoy reading this blog post!

If you need specialist remedial building works in Wollongong, Sydney, or the South Coast, look no further than Southern Remedial Solutions. We use industry-leading technologies to deliver high-quality solutions to our clients.