How to test for lead paint

22nd September 2015 | By: Dave Smyth

old wooden door with lead paint

Removing lead paint is best done with great care!

Once popular, lead paint is now known as a potential cause a raft of health issues. Over time, a coat of lead paint in the home can slowly cause a deterioration of health for the occupiers, as fine lead particles are ingested; the older, more degraded the paint, the greater the risk to inhabitants. As a result, it is important to know whether there is lead paint in your home, and how much of it there is. This can be especially difficult as lead paint looks almost no different from modern paints. How then, can you tell whether your home is potentially poisoning your family?

Find out more about removing lead paint safely

There are a couple of fast, reliable tests that can be done to determine whether you have lead paint. The simplest, and cheapest, test of lead paint is a logical one: was the house painted before 1965? Although the use of lead based paints in the home was only restricted legally in 1979, the potential health risks of using lead paint were beginning to be understood from around 1960, and the use of lead paints in the home began to subside. However, you can be almost certain that a layer of paint dating from before 1965 was lead based, before 1980, and it is likely.

Scientific Tests for Lead Paint

Of course, dating a layer of paint is not scientifically accurate, nor does it guarantee that the paint is in fact, lead based. Luckily, there are also genuine tests to determine lead content in paint. 5% sodium sulphite solution can be bought from most paint shops, pharmacies, and even Amazon. Sodium sulphite is a hugely useful substance for many things, food preservatives, dye making and most notably in this case, detecting traces of lead.

To test for lead paint using sodium sulphite solution by cutting away a small section of the paint layer until the back of that layer of paint is shown. A drop of 5% sodium sulphite solution, applied directly to the spot, will turn black on contact with lead. Much like iodine does on contact with starch, school’s famous potato based experiment.

Testing a couple of spots on each painted surface will guarantee the result, and also provide an indication as to the levels of lead involved. Multiple layers of lead paint can cause an increased risk when it comes to removal.

Finding Lead Traces with Sodium Sulphate

When using the sodium sulphite solution to test for lead, it is vital that care is taken. On older houses, there may be multiple layers of paint on any one spot. To determine which of the layers contains lead, multiple depths may be required. It is important to know which layer of paint, or which layers, are lead based, as this will determine the strategy for removing or repainting.

Lead based paint is most hazardous to health when it is reduced to fine particles. Naturally, the aging of a paint layer will cause it to flake and degrade, allowing the lead particles to be released in an inhalable state. The removal of a lead paint layer, either by sanding or burning vastly increases this rate of release, so in some cases, where the original paint is in good condition, it may be safer to repaint over the top with a non-lead based paint.

However, in most cases, these lead based layers of paint are over 30 years old, and if the coat is not yet beginning to deteriorate, it soon will. Painting over it is a short term solution at best.


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