No — using a heat gun to strip paint from asbestos cement walls is not safe and should never be attempted. Asbestos cement (often called "fibro" or "AC sheet") was widely used in New Zealand homes built before the mid-1980s, and disturbing it — especially with heat — can release deadly asbestos fibres into the air. This is a serious health and legal issue that every NZ homeowner needs to understand before picking up any tool.
Why Heat Guns Are Especially Dangerous on Asbestos Cement
Asbestos cement products contain chrysotile (white asbestos) or, less commonly, other asbestos types bound into a cement matrix. When the material is in good condition and left undisturbed, the risk is relatively low. However, applying heat from a heat gun does two things that dramatically increase danger:
- It degrades the cement binder, causing the surface to crack, crumble, and release fibres.
- It can aerosolise asbestos fibres along with paint fumes, creating an invisible cloud of hazardous particles that you — and anyone nearby — can inhale.
Asbestos fibres are microscopic and odourless. You cannot see or smell them, and there is no safe level of exposure. Diseases caused by asbestos — including mesothelioma, asbestosis, and lung cancer — can take 20–40 years to develop, which means the danger is easy to underestimate in the moment.
What Does NZ Law Say?
In New Zealand, asbestos removal and disturbance is tightly regulated under the Health and Safety at Work (Asbestos) Regulations 2016, administered by WorkSafe NZ. Key points for homeowners:
- Class A asbestos removal (friable or high-risk asbestos work) must be carried out by a licensed Class A removalist.
- Class B asbestos removal (non-friable asbestos cement in good condition, up to 10 m²) may be done by a Class B licensed removalist. Homeowners working on their own homes may in some circumstances carry out minor non-friable asbestos work, but should check current WorkSafe NZ requirements carefully — but only following strict WorkSafe guidelines.
- Using a heat gun, angle grinder, or any method that generates dust or fibres immediately escalates the risk category and is likely to require a licensed professional regardless of the area involved.
Always check with WorkSafe NZ and your local council before undertaking any work on suspected asbestos-containing materials.
How to Identify Asbestos Cement in Your Home
Asbestos cement was commonly used in NZ homes built before 1990 in products such as:
- Exterior wall cladding (flat or corrugated sheets)
- Eaves lining and soffits
- Internal wet-area linings
- Roofing sheets
You cannot identify asbestos by sight alone. If your home was built before 1990 and you are unsure, arrange for a sample to be tested by an accredited laboratory before doing anything. An asbestos assessor can take samples safely and provide a written report. Find a qualified asbestos specialist on tradedirectory.co.nz.
Safe Alternatives to Heat Gun Stripping
If you have confirmed (or suspect) asbestos cement walls and need to deal with the paint or surface, here are the safer approaches:
| Option | Risk Level | Notes |
|---|---|---|
| Leave it alone / repaint over it | Lowest | Best option if surface is sound |
| Wet-scrape by hand (minimal pressure) | Low–Medium | Only if surface is intact; keep wet to suppress dust |
| Encapsulation with specialist paint | Low | Seals fibres in place; consult a professional |
| Licensed asbestos removal | Managed | Required if material is damaged or large area |
The single safest option for painted asbestos cement in good condition is to paint over it. Products from Resene or Dulux can be applied directly over existing sound paint after appropriate surface preparation — without sanding or heat. Always check the manufacturer's technical data sheet for guidance on painting over existing coatings.
What to Do If the Surface Is Already Damaged
If the asbestos cement is cracked, crumbling, or has already been disturbed:
- Stop work immediately and keep others away from the area.
- Do not sweep or vacuum — this spreads fibres further.
- Dampen the area lightly with water to suppress airborne fibres.
- Contact a licensed asbestos assessor or removalist to assess and manage the situation safely.
For guidance on the NZ Building Code and managing hazardous materials during renovation, MBIE Building Performance is a reliable starting point.
When to Call a Professional
You should always engage a licensed asbestos removalist if:
- The asbestos cement is damaged, friable, or crumbling
- The area involved is larger than 10 m²
- You are unsure of the material's condition or extent
- Any power tools, heat, or abrasive methods have already been used
- You are undertaking a renovation or demolition that involves removing the sheeting
A licensed professional will follow safe work procedures, use appropriate PPE and containment, and dispose of asbestos waste at an approved facility — all required by law. You can find qualified asbestos removal specialists in your area on tradedirectory.co.nz.
Safety note: Never use heat guns, angle grinders, high-pressure water blasters, or dry sanding on any surface you suspect contains asbestos. The consequences can be life-threatening and irreversible.
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