If you have an asbestos roof, there are some risks you should be aware of. The danger really depends on the condition of the roof and whether the material has been disturbed. Asbestos cement sheeting was widely used in Australian homes from the 1940s until the mid-1980s, so if your house was built during that time, there’s a good chance your roof may contain asbestos.
The concern lies with the asbestos fibres. When the material is intact and hasn’t been disturbed, the risk is generally low. However, if the roof starts to break down or if someone cuts, drills, pressure washes, or even steps on deteriorating sheets, those fibres can be released into the air. The World Health Organisation has classified airborne asbestos fibres as a known human carcinogen, meaning there’s no safe level of exposure.
So, are asbestos roofs dangerous? Yes, they can become a hazard as they age. If you’re already concerned about the state of your roof, AMJ Metal Roofing can arrange an assessment to determine what you’re dealing with and what needs to happen next (call 1300 12 ROOF).
When an asbestos roof becomes a health risk
During the first decade or two following its installation, asbestos cement roofing sheeting presented minimal hazard to the occupants in the house underneath. When installed, asbestos fibre remained encapsulated within the cement matrix, making it difficult for these fibres to be released to the environment. For this reason, asbestos was used extensively for years as a roofing material in Australia.
It is only upon degradation of this material that its risks become clear. Through years of UV light, torrential rains, hailstorms, temperature fluctuations and other weathering effects, the cement binding material is slowly broken down until the roofing sheet becomes fragile and incapable of containing the asbestos fibres securely. Once this happens, any movement at all is enough to dislodge these fibres, resulting in asbestos being dispersed into the surrounding area.
But this point is often less than obvious; an apparently intact roof may actually have been severely compromised from prolonged wear and tear. Furthermore, there are certain circumstances that hasten this process significantly, such as the occurrence of severe weather, falling trees, or people walking on the roof to repair an antenna. A professional roof inspection is the only reliable way to determine the actual condition of the material.
Bonded vs friable asbestos on your roof
Most of the asbestos roofs found in Queensland consist of bonded asbestos, which is also known as “non-friable asbestos”. In this form of asbestos, the fibres are fixed in a cement matrix, and under normal conditions, it is relatively safe to handle. The sheets are rigid and cannot be crumbled in your hands.
In contrast to the above, “friable asbestos” is completely different. This is a form of asbestos that can be crushed to dust by applying force using your hands. This type of asbestos is less common on the roofing surface, but could be present in old insulation and pipe lagging, or even in backing materials in the roof cavity. It presents a greater health hazard since it can release asbestos fibres into the air easily.
Here’s the catch: bonded “non-friable asbestos” doesn’t stay bonded forever. Due to weathering over the years, it may transform from non-friable to friable, and consequently release asbestos fibres. For instance, asbestos that was non-friable in 1975 might have transformed into friable form by 2025.
What causes asbestos fibres to become airborne
As the binder for asbestos fibre within asbestos roof cement, anything that compromises the cement matrix can lead to the release of asbestos fibres. Natural degradation and physical damage are the two primary sources of the issue.
Degradation is the process of decay through nature over time. In Queensland, the cement sheeting is gradually destroyed by the ultraviolet rays of the sun. Rainwater removes the surface of the sheeting. Hailstorms crack the surface of the sheeting. Thermal expansion and contraction due to extreme heat and cold take its toll on the structure of the material. After four or five decades, the solid cement sheeting will deteriorate into a crumbling substance.
Physical disturbance is the direct cause. The most damaging thing that you can do to asbestos is pressure wash the roof. This is because this process releases fibres directly into the air. Other activities such as drilling holes, cutting, breaking and damaging of sections, walking over aged materials, or blasting the roof space with compressed air cause disturbance of the material and subsequent releasing of harmful asbestos fibres. Even a skilled tradesman who does not realise what material they are working with can release asbestos fibres while doing roof work.
Warning signs your asbestos roof is deteriorating
Deterioration does not come calling in one big crash. Instead, it occurs progressively, and awareness of the signs will enable timely actions when the situation arises.
The first visual indication of damage is surface discolouration. The once grey asbestos cement sheeting has started showing light patches on its surface in the form of a chalky substance. What this means is that the cement binding agent is deteriorating, and the protective surface layer is wearing off. When you observe powder-like deposits accumulating on the sheets, which may be seen by using binoculars from the ground in some instances, the deterioration process is already well underway.
Hairline cracks and chipping are further stages of deterioration. Look out for cracks running along the corrugations of the sheeting, together with chips in areas where overlapping takes place, and fragments found around fixing points. A damaged roof with such visible cracks is continually shedding fibres whenever there is wind or rainfall. These are among the clearest signs your home needs a roof replacement.
Stains caused by water on the interior ceiling could mean the sheets have broken apart, or the seal around fasteners has been compromised. If your roof is made of asbestos and there are fresh water stains, the damage may go much deeper compared to what is evident from the exterior.
Growth of moss and lichen is not hazardous, but it holds in moisture and leads to rapid disintegration of the cement matrix beneath. Sheets covered with moss or lichen are usually in a worse state internally compared to how they look externally. When you find these signs on a roof suspected of containing asbestos, avoid climbing onto the roof. The sheets may break, and you may inhale fibres. You’re also at risk of falling through.
Health risks of asbestos exposure
Australia ranks high on the scale of asbestos-related diseases, a consequence of the widespread use of asbestos-containing materials in buildings during the 20th century.
The reason asbestos is so dangerous is due to its physical properties. The strands of asbestos are very fine (an individual asbestos strand may reach a width of seven hundred times finer than that of a strand of hair), and when breathed in, they become lodged inside the lungs. The body cannot break them down or excrete them; they remain trapped in the lungs for years and even decades to come.
Mesothelioma
Mesothelioma is an aggressive form of cancer that occurs in the thin layer of tissue lining the lungs, the abdominal organs, or sometimes the heart. Mesothelioma can occur as a result of exposure to asbestos in most cases, and this can occur even with low or limited exposure. It is virtually impossible to determine the safe threshold for exposure.
The condition is generally deadly; the median life expectancy after diagnosis is about 12 months. Australia is among the countries that have the highest incidence rate of mesothelioma in the world, averaging 700 diagnoses per year. The cause of this condition is either occupational or environmental exposure to asbestos, with the latter becoming more prevalent due to the deterioration of asbestos materials in domestic dwellings.
Lung cancer and the link to smoking
Asbestos exposure has been shown to be a factor that causes lung cancer regardless of smoking. However, when both asbestos exposure and smoking occur simultaneously, the danger becomes extremely amplified. The effect of both asbestos exposure and smoking on a person’s likelihood to develop lung cancer is known to be 50-90 times greater than those without either risk factor, depending on the severity of the exposure and its duration.
If you are a smoker or a person who used to smoke and lives in a house with an old asbestos roof, then you should consider yourself at an especially high risk. This is due to the fact that asbestos fibres create a constant state of inflammation within the lungs, while cigarette smoke further aggravates it and prevents the lungs from eliminating any harmful substances.
Asbestosis
Long-term exposure to asbestos fibres leads to scar tissue formation in the lungs. This scar tissue impairs the lungs’ ability to allow oxygen from the air we breathe to enter the bloodstream.
The symptoms include difficulty breathing, a dry, crackling sound in the lungs during inhalation, and feelings of tightness in the chest and tiredness. This disease cannot be cured, but treatment aims at alleviating the symptoms. Asbestosis usually occurs following prolonged exposure to asbestos, and not a one-time event, which explains why an asbestos roof that deteriorates over time poses such a threat to people living under it.
Why symptoms take decades to appear
The gap between exposure and illness is what makes asbestos so difficult to take seriously in the moment. Symptoms of both mesothelioma and lung cancer, including asbestosis, usually show up decades after the exposure period, somewhere in the range of 15 to 40 years.
Sometimes it takes even longer. The problem with this is that one person who lives for years in the same house with a deteriorated asbestos roof will never know that there is anything wrong with their lungs because the process of damage goes without any physical symptoms. Your body does not tell you that it has stored toxic fibres in its tissues.
This is one more reason why people today suffering from diseases caused by asbestos fibres became infected during the 1970s and 1980s, when asbestos was actively used everywhere.
How asbestos roofs contaminate beyond the roof itself
When you hear about asbestos, you probably think of the dangers of breathing in fibres that can be present near roofs. However, the issue is much bigger and often gets overlooked. The reality is that when asbestos cement roofing starts to break down, it releases tiny fibres continuously. Rain can wash these fibres off the roof, sending them into gutters. From there, they travel through downpipes and might end up in stormwater systems, garden beds, or even rainwater tanks. If you live in an area like South East Queensland, where many homeowners collect rainwater for daily use, you could be using water that’s passed through asbestos-contaminated surfaces, which is quite concerning.
Moreover, these fibres can build up in your roof cavity. Whenever there are cracks or gaps around where the roofing sheets connect, fine asbestos dust can filter down. Over the years, this dust settles on insulation, wooden framework, and even on top of ceiling panels. Whenever someone accesses the roof space (whether for maintenance, installing lights, or if the wind creates pressure), it can stir up these settled fibres, pushing them into the living areas below.
The soil around your house is also at risk. Rainwater runoff from your roof can deposit fibres into the soil right next to your home. Over time, this creates an area of contamination, especially in garden beds where children might play or pets might dig. If you’ve noticed a grey, powdery substance beneath the edge of an older fibro house, it could very well indicate asbestos-contaminated soil.
Additionally, stormwater systems can carry these contaminants even further from your property, which raises alarms for local councils and regulators, especially during property sales or development projects.
For homeowners, having an asbestos roof that’s deteriorating can lead to serious problems beyond just the roof itself, affecting gutters, rainwater supplies, garden soil, and stormwater runoff. It’s crucial to address every pathway of contamination rather than just replacing the roof, so you can genuinely ensure your home is safe from health risks associated with asbestos exposure. AMJ’s asbestos roof replacement process includes cavity cleaning and contamination management as part of the full re-roof scope.
What you should never do to an asbestos roof
If you’re dealing with a property that has asbestos, it’s important to know that certain actions can release harmful asbestos fibres into the air. The good news is that these situations are completely avoidable if you understand the risks involved.
First off, never pressure wash an asbestos roof. Using high-pressure water can blast fibres right off the roof, spreading them over your yard, gutters, and even into the broader environment. Just one session of pressure washing can contaminate your entire property and potentially affect nearby homes as well. Many people aren’t aware that their roof contains asbestos, which is why this happens.
Also, avoid drilling, sawing, cutting, or breaking any asbestos sheets. Any mechanical action that disrupts the cement materials can release a dangerous burst of fibres. This includes tasks like drilling holes for antenna mounts, installing TV brackets, adding solar panels, or making plumbing penetrations. If you think there might be asbestos in your roof, make sure to inform any tradespeople beforehand. It’s best to have a licensed asbestos professional evaluate the situation first.
Walking on old asbestos sheeting is another big no-no. After years of exposure to weather, these sheets can become brittle. Walking on them can crack the material and release fibres into the air. Plus, you could risk falling through, since the structural integrity of aged sheets may not support an adult’s weight.
Using compressed air, leaf blowers, or even dry sweeping in or around areas with asbestos can also cause problems. These methods can stir up any settled dust, turning it airborne. If dust has gathered in your roof space (common with old asbestos roofing), blowing air can send those harmful fibres into your living spaces through gaps in light fittings, vents, and ceiling joins.
Finally, don’t try to remove asbestos roofing on your own. In Queensland, if you need to remove more than 10 square metres of bonded asbestos, it has to be done by a licensed professional. Not only are there severe penalties for illegal removal, but you also put your health, and that of your neighbours, at substantial risk from exposure to asbestos fibres.
The best advice is straightforward: just don’t disturb the material. If you have any work that needs to be done around an asbestos roof, always get it assessed by a qualified expert before proceeding.
Is it safe to leave an asbestos roof in place?
The safety of an asbestos roof really depends on its current state. If the roof is in great shape (meaning the sheets are intact, with no cracks, erosion, or other signs of damage), it poses a low risk in the short term. That’s because the asbestos fibres are still contained within the cement and aren’t being released into the air.
However, “great shape” is a temporary status that diminishes with time. The roof is aging, and factors like sunlight, temperature changes, rain, and hail constantly wear down the cement, even if you can’t see the issues right away. A roof that looks good today might really start to show its age in just a few years.
There are also practical challenges with keeping the roof as is. You can’t walk on it for maintenance or pressure wash it, and adding solar panels requires specialised work. Anyone working around the roof needs to be cautious and aware of the asbestos. So, the roof controls some aspects of your maintenance and safety.
If you start seeing any signs of deterioration, like chalking, cracks, or even moss that traps moisture, it may be time to consider removal. Even low levels of exposure can pose a risk over time. Moreover, the contamination doesn’t just sit on the roof; it can spread to gutters, the roof space, soil, and water systems.
For homeowners with roofs that are 30 to 40 years old, the real question isn’t whether it’s safe to leave it. Instead, it’s about how much longer you can count on it being relatively low-risk. It’s wise to tackle the situation on your terms rather than waiting for an emergency or a sale. Understanding the asbestos removal and replacement costs upfront makes it easier to plan ahead rather than react under pressure.
Insurance and property value complications
Even if your roof is in relatively good condition, the asbestos issue can actually cost you financially, without even considering the health risks.
Some Australian home insurance companies will provide coverage for a house with an asbestos roof; however, most put restrictions or limitations on their policy. In some cases, they may exclude any damage to the roof from being covered under their policy, or alternatively, damage to other areas of the property may be included while not covering the costs of the removal and replacement of the asbestos roof. There is an obvious problem here, whereby, should the asbestos roof be damaged by a storm, it is possible that the owner would have to pay all expenses associated with the removal and replacement of the asbestos roof, which is estimated to cost anywhere from $15,000 to $40,000. AMJ handles storm damage and insurance repairs across Brisbane and can help you navigate the claims process if your roof is damaged.
Some insurance companies might refuse coverage altogether if the structure is known to have an asbestos roofing system. In addition, failure to disclose this problem during the application or renewal process could result in a denied claim later on.
When it comes to the value of the home, an asbestos roof poses a serious warning sign for potential buyers and construction inspectors alike. These types of roofing structures are often identified during pre-inspection surveys and marked as hazardous. This will give the buyer enough of a reason to bargain the price down, or even abandon the purchase altogether. It doesn’t matter how attractive the property was before, the prospect of dealing with an asbestos roof installation could drive down its worth.
A roof replacement prior to selling takes away any liabilities associated with this material. The house looks better for inspection, and there isn’t anything hazardous left in it. You won’t have to rely on negotiating from a disadvantageous position. For a clearer picture of the investment involved, our breakdown of roof replacement costs covers the key variables.
How asbestos roof removal actually works in Queensland
The entire process is highly regulated every step of the way, from the initial notification to waste disposal. You cannot simply engage any general roofer or handyman in this process without the risk of breaching health regulations. Knowing how the removal process goes will enable you to evaluate the quote and ensure that your expectations match those set by the roofer.
As part of the asbestos removal process, there needs to be a site assessment done by an accredited asbestos professional who assesses the state of the roof as well as the type of asbestos involved, and whether the roof cavity has been contaminated. After this is completed, a removal strategy is developed which includes how the materials are removed, transportation and how it should be disposed of.
Prior to conducting any asbestos removal process at the site, the removalist is supposed to notify WHSQ of their intention. Notification is an important requirement of the law and must contain the details of the removal, including the type of asbestos involved and the control measures that are involved in the process.
Licensing requirements and air monitoring
Any removal of asbestos that exceeds 10 square metres in Queensland must have a minimum of a Class B asbestos removal license. Removal of friable asbestos, on the other hand, must be performed by a holder of a Class A license, which entails additional restrictions in terms of the training, tools, and procedures involved.
Asbestos sheets are not touched directly, but with the help of personal protective equipment such as disposable coveralls and P2 respiratory masks (or supplied-air respirators for friable work). Air monitoring takes place before, during, and after the process to ensure that the asbestos fibres do not exceed the allowable limit. An independent hygienist or occupational health expert normally performs air monitoring.
The air monitoring test is proof that the area can now be safely reoccupied. No clearance means no assurance that the process went smoothly. The process involves containment of the area through the posting of warning signs and keeping the sheets wet to minimise airborne fibres. Sheeting is removed in one piece without breaking it and then individually packed in plastic sheets before transfer to asbestos waste transportation vehicles.
What happens after the asbestos is removed
After the removal of the asbestos, a thorough inspection of the roof framing is carried out. Most of the time, the roof framework is strong enough to support the new metal roof. The rafters or battens, if damaged due to water leakage problems, are either repaired or replaced before the installation of the new roofing material.
All dust and debris containing asbestos fibres in the roof cavity are then cleared by following the recommended practices, which include use of high efficiency particulate air filter vacuums and wet cleaning procedures as opposed to sweeping or using leaf blowers, which could lead to re-suspension of asbestos fibres.
Lastly, installation of the new roof follows the recommended procedures. A new metal roof, such as Colorbond and Zincalume, complete with new flashings, ridge capping, gutters and downpipes, is installed. The property becomes an asset instead of a liability, with the new roof lasting for years with minimal or zero maintenance required. To most people, the difference in appearance is clear.
Why metal is the preferred replacement for asbestos roofing
Asbestos became popular for use in roofs due to the following qualities: it could withstand fires, it had durability in extreme weather conditions, it was light compared to tiles, it did not corrode, it was termite proof, and it was inexpensive to produce. Those were its strong points. However, it was the health risks associated with it and not the performance that made asbestos dangerous. As such, the ideal replacement material needs to match or exceed that original performance.
Modern Colorbond steel meets the above specification perfectly. For instance, asbestos became popular due to its fire-resistant nature. The Colorbond steel is fire-resistant and meets Bushfire Attack Levels (BAL) that are applicable in bushfire areas of Queensland. Therefore, in the state of Queensland, where there are bushfires, having a steel roof offers similar fire-resistant qualities as asbestos while remaining health-safe. You can learn more about Colorbond roofing and why it’s the most popular choice for Brisbane re-roofs.
Durability against weather conditions comes second. Asbestos cement was fragile and easily damaged by UV and hail. Colorbond is designed specifically for Australia’s climate and features five coats of paint that protect against UV, corrosion, cracking and flaking. In addition, BlueScope provides Colorbond materials with up to a 36-year warranty for the steel and coating. While an asbestos roof may last between 30 and 40 years before being dangerous, a correctly installed Colorbond roof can serve for more than 50 years without problems.
Weight plays into the favour of metal, too. Since asbestos cement is more heavy than metal, replacing the first one with the latter means decreasing the total load of the roof, which is especially good for old buildings in Queensland, with timber construction that has carried loads for decades. A decrease in weight means less pressure on old battens, rafters and supporting walls.
It is also the thermal performance that makes metal roofing superior to Asbestos roofing. With the use of Colorbond’s Thermatech reflective technology, energy savings in terms of reduced heating can be realised by minimising heat gain through the roof. This was something not possible with Asbestos Cement roofing. Paired with proper roof insulation (which AMJ installs as part of a full re-roof), a new metal roof can significantly reduce the heat load entering your home compared to the old asbestos sheeting it replaced.
When you’re replacing a roof that was chosen for its practical qualities, the replacement should meet the same brief. Metal does. If you’re weighing up Colorbond against Zincalume for your replacement, our Colorbond vs Zincalume comparison breaks down the key differences.
Get your asbestos roof assessed
If you have an asbestos roof, or if you are unsure about whether your roof has asbestos, the first thing you need to do is get an inspection done. AMJ Metal Roofing provides asbestos inspections and replacements for asbestos roofs in Brisbane, the Gold Coast, Sunshine Coast, Ipswich and Toowoomba.
After the inspection is done, we will discuss with you what needs to be done and will provide you with a scope of works and quotation for removing your asbestos roof and replacing it with a Colorbond or Zincalume metal roof that comes with our 10 year warranty.
Call 1300 12 ROOF (1300 127 663) to arrange an inspection, or request a quote through our website.
FAQs
Can I paint or seal over my asbestos roof instead of replacing it?
Yes, it’s certainly possible to use a protective coating on an asbestos roof that is in good shape; however, it will only delay the process of degradation for some time. Unfortunately, it will not solve the core problem: asbestos will remain in place, the cement-based layer will keep deteriorating under the coating, and any subsequent work on the roof will necessitate dealing with asbestos. In most cases, those who opt for roof coating wind up having to replace the entire roof within five to ten years.
Is it legal to remove asbestos roofing myself in Queensland?
It is legal for you to strip off up to 10 square metres of bonded asbestos yourself in Queensland, as long as you observe very stringent safety guidelines during the process. However, if your bonded asbestos exceeds 10 square metres, you will need to hire an asbestos removalist who has a Class B license. Any friable asbestos should always be stripped off by someone with a Class A license, irrespective of how much there is.
How long does an asbestos roof replacement take?
On average, the duration for asbestos roof replacement can range between 3 to 5 days depending on the size of the house and the shape of the roof. If the roof is big or complicated in shape, the duration would increase. For example, the duration for asbestos removal would take one to two days, while the rest would be used for installing the new metal roof.
Does an asbestos roof affect my home insurance?
It can. Some insurance companies will deny claims for damages resulting from storms on an asbestos roof, others will add limitations to your coverage, while others will simply refuse to insure any property with an asbestos roof. If you don’t mention your asbestos roof, there is a possibility that your claim will be denied.
How do I know if my roof actually contains asbestos?
If your property was constructed or refurbished prior to 1990, it is very likely that asbestos exists in the roof. There is only one method to determine this; by conducting a test on the roofing materials. An asbestos assessor extracts a small amount of material from the roof and submits it for testing at an NATA-accredited laboratory. It cannot be determined solely based on visual examination since the asbestos cement sheet may resemble fibre cement sheeting.
