Can I Apply Encapsulant Spray to Damaged Asbestos Cement Cladding Myself?

Applying encapsulant spray to damaged asbestos cement cladding is technically something a homeowner may do in certain limited circumstances under New Zealand law — but the rules, risks, and preparation requirements are serious enough that most experts strongly recommend hiring a licensed asbestos removalist instead. Before you pick up a spray can, you need to understand exactly what you're dealing with and what the law requires.

What Is Asbestos Cement Cladding and Why Does It Matter?

Asbestos cement (AC) cladding — often called fibrolite or Super Six — was widely used on New Zealand homes built before the late 1980s. It contains chrysotile (white) asbestos fibres bound in cement. When the material is in good condition and undisturbed, the fibres are largely locked in place. However, when it is damaged, cracked, weathered, or friable, fibres can become airborne and pose a serious health risk, including mesothelioma and lung cancer.

If your cladding is damaged, it is classified as damaged non-friable asbestos-containing material (ACM). This changes what you are legally allowed to do.

What Does NZ Law Actually Say?

Under the Health and Safety at Work (Asbestos) Regulations 2016, the rules differ between Class A and Class B asbestos removal:

• Class B removal covers non-friable ACM in areas under 10 m². Homeowners working on their own domestic residence may be exempt from needing a Class B licence for this limited scope — confirm the current exemption conditions with WorkSafe NZ, as requirements can change.
• Class A removal covers friable asbestos or any ACM over 10 m², and must be carried out by a licensed Class A removalist — no homeowner exemption applies.

Encapsulation is not removal, so it sits in a grey area. However, WorkSafe NZ is clear that any work that disturbs asbestos — including preparation work before encapsulation — must be managed carefully, and if the material is friable or the area is large, a licensed professional is required.

As a homeowner, you should contact WorkSafe or a licensed asbestos assessor to confirm which category your cladding falls into before doing anything.

What Is Encapsulant and Does It Actually Work?

Encapsulant is a penetrating or bridging sealant sprayed or rolled onto ACM to bind loose fibres and prevent them becoming airborne. It is a management strategy, not a permanent fix. It does not make asbestos safe forever — it buys time and reduces immediate risk while a longer-term plan (such as full removal or over-cladding) is arranged.

Encapsulants are available from specialist suppliers and some trade stores. Always check the product is specifically rated for asbestos encapsulation and follow the manufacturer's data sheet precisely.

Can a Homeowner Apply It Safely?

If your cladding is non-friable, the damaged area is small (under 10 m²), and you are the owner-occupier of a domestic residence, you may be able to apply encapsulant yourself. However, you must:

• Get a professional asbestos assessment first. An independent licensed asbestos assessor can confirm the material type, condition, and fibre risk. This is strongly recommended and in many situations effectively required before any work begins.
• Use the correct PPE. At minimum: a P2-rated half-face respirator (not a dust mask), disposable coveralls (Tyvek-style), gloves, and eye protection. Refer to WorkSafe NZ guidance on asbestos PPE requirements.
• Never dry-brush, sand, water-blast, or use power tools on the surface before encapsulating — these actions release fibres and may push your work into Class A territory.
• Wet the surface gently with a fine mist of water before any minimal preparation, to suppress dust.
• Seal off the work area and ensure no other people (especially children) are nearby.
• Dispose of all waste correctly. PPE, plastic sheeting, and any debris must be double-bagged in heavy-duty plastic, labelled as asbestos waste, and taken to a council-approved disposal facility. Check with your local council for the nearest site.
• Keep records. Document what you found, what you did, and what products you used. This is important for future owners and for any building consent purposes.

What You Must NOT Do

• Do not attempt encapsulation on friable (crumbly, easily crushed) asbestos — this is Class A work and legally restricted to licensed removalists.
• Do not work on areas larger than 10 m² without a licensed contractor.
• Do not use standard paint as a substitute for a proper encapsulant product.
• Do not ignore the damage and hope it resolves itself — weathered AC cladding deteriorates further over time.

Building Consent Considerations

Encapsulation alone generally does not require a building consent, but if you are planning to over-clad or replace the asbestos cladding as a next step, you may need consent depending on the scope of work. Always check with your local council. The MBIE Building Performance website has useful guidance on Schedule 1 exemptions and when consent is required.

When to Call a Professional

You should always call a licensed asbestos removalist or assessor if:

• The damaged area is larger than 10 m²
• The cladding is friable (crumbles when touched)
• You are unsure whether the material contains asbestos
• You are a landlord (additional obligations under tenancy and health and safety law may apply — check with WorkSafe NZ and Tenancy Services)
• You feel uncomfortable or unsure at any point

A licensed professional will carry out an asbestos survey, prepare a safe work method statement, use commercial-grade PPE and containment, and provide you with a clearance certificate. The peace of mind is well worth the cost. You can find qualified asbestos removal specialists in your area on tradedirectory.co.nz.

Sources & Further Reading

• WorkSafe NZ – Asbestos guidance and regulations
• MBIE Building Performance – Building consent information
• BRANZ – Asbestos in homes
• Tenancy Services – Healthy Homes Standards
• Standards NZ – NZS guidelines