You can't tell whether paint contains lead just by looking at it, so the only way to know is to test it. It's the first step before any work on lead paint on heritage homes. If your house was built in the 1980s or earlier, Health New Zealand advises presuming it has lead paint until a test shows otherwise. Testing is cheap and quick. You can use a home lead paint test kit from a paint store, take a paint flake to a store or your public health unit to be tested, or send a sample to a laboratory for a definite answer. Test before anyone sands, scrapes or water blasts.
How do I know if my house has lead paint?
Start with the age of the house. The government guidelines say paint from before 1970 is almost certainly lead-based and paint from before 1980 may be, and Health New Zealand advises presuming lead in any building from the 1980s or earlier. Most villas, bungalows and weatherboard homes fall in that range. Even a house with recent paint can have lead in the layers underneath.
Then test the paint itself, especially:
- Weatherboards, fascias and barge boards outside
- Window frames, sills and doors, inside and out
- Skirting boards and other painted woodwork
- Anywhere the paint is flaking, chalking or worn through
What does lead paint look like?
Lead paint doesn't look different from other paint. Health New Zealand, BRANZ and Consumer NZ all say you can't identify it by appearance. Age tells you more than appearance: on a heritage home, assume the bottom layers contain lead until a test shows they don't.
How do you test for lead paint at home?
Home lead paint test kits are sold at paint stores, including Resene ColorShops. The method the government guidelines describe is simple: clean the surface, cut a small notch through all the paint layers to the bare wood, and apply the test solution to the exposed layers. A colour change means lead is present. Follow the instructions in your kit.
The guidelines describe the classic sodium sulphide test:
- Clean the painted surface.
- With a clean knife, cut a notch about 1 centimetre long through to bare wood, so every layer shows in the cut.
- Rub the solution onto the exposed layers with a clean cotton bud.
- If the paint turns brown or black, lead is present. No black colour means a negative result.
Limits to know about:
- These tests show whether lead is present, not how much.
- A colour change can be hard to see on dark paint.
- Test solution goes off with age and heat. The guidelines say not to use sodium sulphide solution older than about three months.
- Protect your skin and eyes, and test in a well-aired place.
Other home kits use a different chemical and a pink colour change. Read the instructions for the kit you buy.
Where can you get lead paint tested for free?
Some paint stores test paint flakes in store, and Resene says its ColorShop staff will test a flake you bring in. The government guidelines say public health units test paint flakes for free. In Auckland, contact a health protection officer at the public health service. A free test is a good first check before you decide how the house will be prepared.
To take a sample: scrape off a small flake that includes every layer down to the wood, put it in a sealed bag, and label where it came from.
When should you get a laboratory test?
Get a laboratory test when you need a definite answer, for example before a big renovation or when a home kit result is unclear. Laboratories measure how much lead is in a paint chip. Hill Laboratories, for example, is accredited to test lead in paint and dust, and classifies paint against the joint Australian and New Zealand standard, which defines lead paint as more than 0.1 percent lead in the dry film.
Laboratories can also test household dust, which shows whether lead contamination has already spread into the house. Hill Laboratories suggests getting professional advice before dust sampling, so the samples are taken correctly.
What should you do if the test is positive?
Don't panic, and don't start sanding. Lead paint that is sound and covered isn't a hazard. The risk comes when it's disturbed. Plan the job with lead in mind: either seal it under new coats with careful preparation, or strip it with wet methods and full containment. Keep children and pets away from any work, and talk to painters who can explain how they handle lead.
When you ask for quotes, tell each painter the test result and ask:
- Will you seal the lead paint or strip it, and why?
- How will you contain the dust and flakes?
- How will you clean up, and with what?
- How will you dispose of the waste?
The options are covered in lead paint on heritage homes, and what they cost in lead paint removal cost.
Frequently asked questions
When did lead paint stop being used?
There was no single cut-off. White lead pigments were used in New Zealand house paint until the mid-1960s, and BRANZ records white lead was banned in 1979. Yellow lead chromate stayed in some paint until the late 1970s, and red lead primer was used on wood until the 1980s. That's why the 1980s are used as the safe line for presuming lead.
Can I paint over lead-based paint?
Yes, if it is sound. The government guidelines say a lead-free top coat keeps the risk negligible while it stays intact. Preparing the surface still disturbs some lead, so use wet sanding, catch every flake on a groundsheet and keep children and pets away. Flaking lead paint has to be removed carefully first, or the new coat will fail with it.
Should I be worried if I sanded lead paint?
If you already sanded paint that might contain lead, stop, and clean up properly: wipe surfaces with a damp cloth, throw the cloth away and use a HEPA vacuum, not a household one, then wash work clothes separately. If children or anyone pregnant were exposed to the dust, or you feel unwell, ask your doctor about a blood lead test. Then test the paint before you carry on.
Are home lead paint test kits accurate?
Home kits are a useful first check: they show whether lead is present, not how much. The government guidelines say the sodium sulphide test gives reliable yes or no results when done correctly, and recommend a laboratory test when a more accurate answer is needed. Results on dark paint can be hard to read. If in doubt, get a flake tested by a laboratory.
Ready to repaint?
Once you know what's on your walls, the job can be planned properly, with the right preparation. Tell us about your house and the test result, and we'll arrange an estimate that includes the right preparation.