Check for asbestos before undertaking high-pressure spraying on roofs

What happened?

WorkSafe has been notified of a number of instances in recent years where waterblasting was carried out on roofs which contained asbestos.

In the most recent case, the waterblasting work was carried out on a residential property built in the 1970s that had decramastic roof tiles.

Following the work, debris was identified across the property and inside the home. Testing later confirmed the roof tiles contained chrysotile asbestos and that asbestos-containing material had contaminated both indoor and outdoor areas.

Specialist assessment determined that remediation was required to address the contamination.

What was learned?

This incident highlights the importance of identifying whether asbestos-containing materials may be present before work begins, particularly when working on older buildings.

Decramastic roofing installed before asbestos was phased out may contain asbestos. Before undertaking work that could disturb roofing materials, asbestos risks should be identified and assessed.

Where asbestos-containing materials are known or suspected to be present, appropriate controls should be implemented before work starts. Controls should be selected based on the nature of the work and the risk of disturbing asbestos-containing material.

High-pressure water spraying (including water blasting) must not be used on asbestos or ACM. Likewise, compressed air must not be used on asbestos. Both are specifically prohibited under the Asbestos Regulations.

Thorough planning and assessment before work begins can help prevent asbestos exposure and reduce the risk of contamination to surrounding areas.

Actions to consider

• ACMs may be present before carrying out work on buildings built before the 2000s.
• Identify and assess asbestos risks before undertaking waterblasting or other work that could disturb roofing materials.
• Ensure appropriate controls are implemented where asbestos-containing materials are known or suspected to be present.
• Where asbestos roofing is present, use an alternative method for cleaning that does not involve high pressure water or compressed air. For more information refer to Cleaning weathered asbestos containing roofing and cladding
• If work has already started and asbestos-containing materials are identified or discovered, stop immediately and seek specialist advice.
• Ensure workers understand asbestos risks and relevant safe work procedures.

More information about the safe handling of asbestos can be found at worksafe.govt.nz

High-pressure water blasting should not be used to clean roofing and cladding containing asbestos

Cleaning weathered asbestos containing roofing and cladding