What is radon?
Radon is a naturally-occurring radioactive gas. It has no odour, colour or taste.
What is the source of radon?
Certain rocks and soils contain the radioactive element uranium. The uranium decays radioactively to produce radium which in turn decays to produce the radioactive gas radon.
What are the health effects of radon?
As radon decays radioactively it produces particles called 'radon daughters'. If these are breathed in they can damage lung tissues. In time, this can lead to lung cancer.
What unit is radon measured in?
Radon is usually measured in units called becquerels per cubic metre of air (Bq/m3).
What is the action level for radon?
Current advice from the government is that domestic homes have radon levels of below 200 Bq/m3. Above this householders are recommended to reduce radon levels.
What levels of radon do we find in the UK?
On average, homes in the UK have radon levels around 20 Bq/m3. Levels vary considerably however from place to place and from house to house. In some parts of the country levels exceeding 10,000 Bq/m3 have been found.
Which parts of the country are most affected by radon?
There are some parts of the UK where the higher than normal levels of radon occur due to the underlying geology of the land. The former National Radiological Protection Board - now the Radiation Protection Division of the Health Protection Agency, has produced maps of the UK showing the areas with most potential for radon.
If my house has radon levels over the action level what can I do?
The best way of reducing levels is to stop radon getting into the building. This can be done by one of the following methods, or a combination of methods.
- Installing a radon sump system
- Improving ventilation under suspended timber floors
- Installing positive ventilation in the house
- Sealing cracks and gaps in solid concrete floors
What is a radon sump?
A radon sump is a small space about the size of a bucket, dug under a solid ground floor. A pipe and fan are linked to the space. Any radon is extracted to outside the building. Costs vary but on average a system costs around £750.
How do I improve ventilation under a suspended timber floor?
New air bricks are installed in the walls just above ground level. If necessary this can be combined with a fan system. The flow of air under the property limits the amount of radon entering the house.
What is positive ventilation?
The system blows air in from the loft level. It both dilutes the radon and reduces the amount of radon getting into the house. People who are susceptible to draughts will probably prefer to install a different system.
How do I reduce radon by sealing cracks in the floor?
It is essential that all cracks are sealed. This involves removing carpets and skirting boards. If only 90% of the cracks are sealed, there is unlikely to be a sufficient reduction in radon.
Is the action level for radon at work the same as that for homes?
No. As we spend less time at work than at home, the action level for radon at work is 400 Bq/m3.
Is controlling radon at work advisory or law?
As with all ionising radiation, radon is regulated through the Ionizing Radiation Regulations of 1999.
Where can I get more information on assessing the risk from radon at work.
Advice can be found on the Health and Safety Executive website. Alternatively you can contact your local authority health and safety inspector.
What should I do if the search on a property I am buying states that the property is in a 'radon affected area'?
Firstly, ask the current owners if they have had a radon test done on the property. If they have they should be able to provide you with the test result. If they have not tested the property you have a number of options:
- Go ahead with the purchase and get the property tested once you have moved in. The result will tell you whether or not the radon level exceeds the 'action level'. If it does you can then do any necessary works to reduce the radon level
- Go ahead with the purchase of the property, but negotiate the purchase price to cover any remedial works in the event that the house has radon over the 'action level', then once in the property carry out a test as in 1, above
- Enter into an agreement with the seller of the property whereby a sum of money is kept back from the purchase of the property. This can then be used to pay for any work necessary on the property to reduce radon. This is sometimes referred to as a 'radon bond'. The money should be held by a third party such as a solicitor and a time limit agreed for the property to be tested - for example 9 months
How much money should be retained in the radon bond?
For an average house the cost of installing a 'radon sump' (the best method of reducing levels) is £750 - £1,000. The final amount will need to be agreed with the seller of the property.
The house I am buying was built just a couple of years ago - do I still need to consider a radon bond?
Houses built since 1999 should have had appropriate radon prevention incorporated at construction.