Asbestos cement siding was a staple of New Zealand construction from the 1940s through to the late 1980s. Its fire resistance, durability, and low cost made it popular across residential and commercial building types. The result is that a significant proportion of the country’s existing building stock still contains asbestos-containing materials (ACMs) in their cladding, eaves linings, and other external elements.
For builders, renovators, and trades working on any structure built before the 1990s, understanding where asbestos siding is likely to be present and what obligations apply when it is found is not optional — it is a legal and safety requirement.
How to Identify Likely Asbestos Siding
There are several visual indicators that suggest a material may contain asbestos, though none are definitive without testing. Fibro or fibre cement sheeting from this era typically appears grey and may be becoming brittle with age. Common applications include flat or corrugated weatherboard panels, eaves linings, and internal linings in older homes. Buildings constructed before the early 1990s should be treated as potentially containing ACMs until testing confirms otherwise.
The only way to confirm the presence of asbestos is laboratory analysis of a sample taken by a trained assessor. Visual identification alone is not accepted under WorkSafe NZ requirements.
What WorkSafe Requires
Before any work that may disturb asbestos-containing materials begins, a risk assessment is required. For high-risk work involving friable asbestos, or any removal of more than 10 square metres of non-friable material, a licensed Class A removalist must be engaged. Appropriate personal protective equipment, dust suppression techniques, and decontamination procedures must be in place.
DIY removal of asbestos siding is strongly discouraged and in many cases prohibited. The consequences of getting it wrong are not only regulatory — airborne asbestos fibres cause mesothelioma, lung cancer, and asbestosis, all of which have long latency periods between exposure and diagnosis.
When the Material Is Left in Place
Intact asbestos siding that is in good condition and sealed with paint poses a relatively low risk when it is not being disturbed. The priority is maintaining that condition: ensuring the paint film is unbroken, avoiding drilling, sanding, or cutting, and monitoring for any cracking or deterioration. If damage occurs, professional advice should be sought before any further work proceeds.
Find more health and safety guidance for New Zealand builders and trades, or connect with licensed asbestos assessors and removal specialists in your region.
