Versaperm Vapour Permeability measurement

Radon Permeability


Radon MapEvery year nearly 53,000 people die somewhere in the world because of radon, that's 144 every day. In the UK alone more die through radon than drink driving.  Next to smoking it is the biggest cause of lung cancer.  Half of all the radioactivity you are exposed to every year comes from radon.

According to the HPA over 10% of homes tested in 2007 recorded radon levels that exceeded the level 200 Bq m-3 which is the UK's guideline level for when where remedial action should be undertaken.

To check the background level of radiation in anywhere in the you can check the UK Government’s Public Health England organisation on

The Building Regulations in England, Scotland, Wales and Northern Ireland require that all new buildings or extensions in "Radon Affected Areas" have protective measures installed during construction and as you can see, large areas of the UK are affected. The most common of these is the geomembrane which largely prevents radon entering the house and diverts it to the atmosphere.

To decide on the correct geomembrane for any area you need to know the building's radon vapour permeability of the membrane and building's structure.

However, measuring this has traditionally been slow, complex and very expensive – but now Versaperm has introduced a permeability meter that can measure this flow through either a sample of building material or a complex, multi-layer, structural element. By law any such measurements using radioactive gases need to be carried out in specially certified areas.

Our permeability meter is simple to use, requiring minimal training at most, yet it offers high precision and repeatability.  It is accurate in measuring radon in the Parts Per Million (PPM) range.  As well as the equipment we also provide a specialised laboratory testing service.

The new system can optionally be configured to measure permeability for other gases including water vapour, carbon dioxide, hydrocarbons, solvents, oxygen, hydrogen, helium and many more.  The equipment is easy to use, highly automated and computerised.

Because of the high cost of radon testing a clever technique has been evolved that reduces the overall reduce cost of the process.  Normally only one sample out of five is actually tested against radon with the other four being tested (at a far lower cost ) using a different noble gas as a proxy. Methane is commonly used in this role as it has approximately the same size molecule as radon and seems to give similar results.  The radon tests act as a check to ensure the results are both related and reliable. This allows a geomembrane manufacturers to develop their new barrier materials at a far lower cost – and once the materials and manufacturing techniques have been developed, the barrier can simply be re-tested to ensure it complies fully with the appropriate regulations.


For an article on Radonclick Hide and Seep - The story of radon in the home



Radon is a colourless, odourless and tasteless radioactive gas produced naturally by the decay of uranium in the ground beneath us. 

Mainly it escapes to the air where it is so dilute it doesn't really cause any problems. However, when seeps into buildings, usually through the foundations, it can build up to dangerous levels.

The problem is at its worst in areas where that are rich in granite, though it is also associated with ironstone, phosphatic rocks and shales rich in organic material.
To a lesser degree it can also be associated with common rocks such as limestone.

Radon vapour permeating into building