Asbestos in Homes: Identification and Management

For much of the 20th century, asbestos was used in building materials because it was heat-resistant, fire-resistant and insulating. WorkSafe says many buildings in Aotearoa New Zealand have asbestos in them, and homes built before 1 January 2000 may contain some asbestos materials.

If your home was built or renovated before 1 January 2000, treat suspect materials carefully. This is not cause for panic, but it is a reason to check before cutting, drilling, sanding, water blasting, renovating or demolishing materials that could contain asbestos.

Where Asbestos Might Be in Your Home

Asbestos was used in a remarkable variety of building products. Some of these were structural components that remain hidden within walls and ceilings. Others were surface finishes that you might see and touch regularly without realising what they contain.

• Roofing: Corrugated cement roof sheets and ridge capping were commonly made with asbestos.
• Cladding: Flat cement sheets used as exterior cladding often contain asbestos, particularly the material known as fibrolite.
• Eaves and soffits: The panels lining the underside of roof overhangs are frequently asbestos cement.
• Interior walls and ceilings: Some wall linings, particularly in wet areas, used asbestos-containing boards.
• Textured ceilings: Some spray-on textured finishes contained asbestos.
• Floor tiles and backing: Vinyl floor tiles and the backing sheets beneath them often contain asbestos.
• Insulation: Older hot water cylinder wraps and pipe lagging may contain loose-fill asbestos insulation.
• Fencing: Corrugated or flat asbestos cement sheets were popular for fencing.

The widespread use of asbestos means renovation, repair, maintenance and demolition work on older homes can encounter asbestos-containing materials. WorkSafe says to check before starting work, not to disturb suspected asbestos, and to treat uncertain materials as asbestos.

Understanding the Risk

Asbestos fibres can cause serious diseases including lung cancer, mesothelioma and asbestosis. WorkSafe says all forms of asbestos are harmful to humans, but the risk of harm depends on condition and how easily fibres are released into the air. Fibres are more likely to be released when materials are friable, in poor condition or disturbed by work such as sanding, drilling, cutting or water blasting.

• Friable asbestos (loose, crumbly material like pipe lagging) is the highest risk because fibres are easily released.
• Bonded asbestos (fibres locked in a solid matrix like cement sheets) is lower risk when intact.
• Condition matters: Damaged, weathered, or deteriorating materials release more fibres than intact ones.
• Disturbance is dangerous: Cutting, drilling, sanding, or breaking asbestos materials releases large quantities of fibres.

Non-friable asbestos materials are less likely to release fibres when they are in good condition and not disturbed. The risk changes if the material is weathered, cracked, crumbling, cut, drilled, sanded, water blasted or removed without suitable controls.

Testing and Identification

You cannot identify asbestos by looking at it. Many materials that look like asbestos do not contain it, and many that look harmless do. The only way to confirm whether a material contains asbestos is to test a sample, and WorkSafe says asbestos sampling should only be done by a reputable contractor.

Testing involves collecting a sample of the suspect material for analysis. Sampling itself can release fibres if it is not done properly, so use a reputable contractor rather than taking samples yourself.

If you are planning renovations, ask a reputable asbestos contractor or asbestos surveyor about checking areas that may be disturbed. WorkSafe says asbestos surveyors visually inspect suspected areas, take samples and provide a report of their findings. Licensed asbestos assessors have a separate clearance and air-monitoring role for some removal work.

Management Options

When asbestos is confirmed in your home, the management approach depends on the amount, condition, location, access, whether work needs to happen on or near it, and whether you are a homeowner, landlord or person arranging contractor work.

If asbestos-containing materials are in good condition and will not be disturbed, a contractor may advise managing them in place rather than removing them immediately. Management can include recording the location and condition, avoiding damage, warning people who may work near it, and checking whether landlord or workplace duties require an asbestos management plan.

Encapsulation involves coating asbestos-containing materials to reduce fibre release. Get contractor advice first, because the condition, location and future maintenance plans affect whether sealing, repair, enclosure, management in place or removal is appropriate.

Removal may be needed where material is damaged, deteriorating or likely to be disturbed by work. Check whether the work requires a Class A or Class B licensed removalist: WorkSafe says Class A covers any type or quantity of asbestos, Class B covers non-friable asbestos, and up to and including 10m2 of non-friable asbestos may not require a licence if the work is still performed safely.

The Removal Process

Licensed asbestos removalists should follow an asbestos removal control plan and safe work procedures to minimise fibre release and exposure. For Class A friable asbestos removal, WorkSafe says an independent licensed asbestos assessor is required for air monitoring and clearance certificates.

Removal of non-friable asbestos, such as asbestos cement sheets, still needs careful controls. WorkSafe says all removal work needs suitable controls, correct PPE/RPE, safe methods, decontamination facilities and disposal of asbestos waste in a licensed landfill.

Costs vary by the type, quantity, condition and location of the material, whether the work is friable or non-friable, access, containment, clearance, disposal, scaffolding, weather protection, replacement materials and consent or contractor requirements. Get itemised quotes and check the contractor's licence, insurance and disposal approach.

Planning Renovations

If you are planning renovations on a home that might contain asbestos, build testing and potential removal into your project timeline and budget from the start. Discovering asbestos mid-project creates delays, additional costs, and safety risks that proper planning would have avoided.

Before work begins, identify suspect materials and get contractor advice or sampling where needed. If asbestos is present in areas that will be disturbed, plan safe management or removal before physical work starts. Check building consent requirements with your council: MBIE says building owners are responsible for deciding whether work is exempt and making sure exempt work still complies with the Building Code.