If your home was built before 1980, there is a real chance your floorboards were painted with lead-based paint at some point. Sanding lead paint without proper precautions generates fine toxic dust that is a serious health hazard — particularly for children, pregnant women, and anyone spending time in the home. Testing before you sand is not just good practice; in many situations it is a legal and ethical obligation.
Why Lead Paint on Floors Is a Serious Risk
Lead was commonly used in NZ house paints until the late 1970s. Even if your floors look bare or have been coated over, old lead paint layers can still be present beneath the surface. When sanded, lead particles become airborne and can be inhaled or ingested. WorkSafe NZ classifies lead dust as a hazardous substance, and exposure can cause lasting neurological damage, especially in young children.
The risk is not just to you — it extends to your family, neighbours, and any tradespeople working on site.
How to Tell If Your Home Might Have Lead Paint
Before testing, consider these risk indicators:
- Your home was built before 1980 (the older, the higher the risk)
- The floors have multiple layers of old paint
- Paint is chipping, chalking, or has a distinctive chalky or enamel-like finish
- The home has had minimal renovation since it was built
These are warning signs only — the only way to know for certain is to test.
Testing Methods: Your Options
1. DIY Lead Test Kits
Swab-style lead test kits are available from hardware stores such as Bunnings and Mitre 10. These kits use a chemical reaction (typically sodium rhodizonate or sodium sulphide) that changes colour in the presence of lead.
How to use them:
- Sand or score a small area to expose any underlying paint layers
- Apply the swab to the exposed surface
- A colour change (often red or pink) indicates the presence of lead
Limitations: DIY kits can produce false negatives, particularly when lead is present in lower concentrations or buried under many paint layers. They are a useful first step but are not definitive.
2. Professional XRF Testing
X-ray fluorescence (XRF) testing is the gold standard. A licensed assessor uses a handheld XRF analyser to scan surfaces non-destructively and give an immediate, accurate reading of lead content. This is the method recommended for any situation where you need certainty — especially before commercial sanding work or if you have young children in the home.
Search for a qualified lead assessor or environmental testing company in your area. Many floor sanding professionals and occupational hygienists offer this service.
3. Laboratory Paint Sample Analysis
You can collect a small paint chip (including all layers down to bare timber) and send it to an accredited laboratory for analysis. This gives a precise lead concentration result. Ask the lab for a result in milligrams per kilogram (mg/kg) — levels above 1,000 mg/kg (0.1%) are generally considered hazardous under NZ guidelines.
What the NZ Building Code and Regulations Say
While there is no single NZ law that specifically bans DIY sanding of lead paint in a private home, WorkSafe NZ has clear guidance on working safely with hazardous substances. If you are a contractor or employer, the Health and Safety at Work Act 2015 requires you to manage the risk of lead exposure for workers and others. Residential landlords also have obligations under the Healthy Homes standards to maintain safe living conditions.
BRANZ provides research and guidance on hazardous materials in older NZ homes and is a useful reference for understanding the scope of the issue.
What to Do If Lead Paint Is Found
If testing confirms lead paint is present, do not proceed with standard sanding. Your options include:
- Encapsulation: Applying a suitable coating over the existing paint to seal it in, rather than removing it. This avoids generating dust entirely.
- Wet sanding or chemical stripping: Reduces airborne dust, but still requires careful containment and disposal.
- Professional lead paint removal: A specialist contractor with appropriate PPE, containment, and waste disposal procedures.
Any lead-contaminated waste must be disposed of correctly — check with your local council for hazardous waste disposal requirements.
When to Call a Professional
You should engage a qualified professional if:
- Testing confirms lead paint is present and you want the floors sanded or stripped
- Your home was built before 1965 (higher probability of significant lead content)
- Children under six or pregnant women live in or regularly visit the home
- You are a landlord with tenants in the property
- You are unsure about any aspect of testing, containment, or disposal
A professional floor sander experienced in lead paint work will have the correct respirators (minimum P2/P3 rated), full-body coveralls, containment sheeting, HEPA-filtered vacuum equipment, and safe disposal procedures. You can find qualified local floor sanding professionals on tradedirectory.co.nz.
A Note on Safety During Any Testing
Even when collecting a small sample for testing, wear nitrile gloves and a P2 respirator (not just a dust mask). Wet the area lightly before scoring to minimise dust. Seal any sample in a zip-lock bag immediately and wash your hands thoroughly afterwards.
