Will your search unearth the ‘Radon Affect’?

Stuart Durrant, Conveyancing Partner at Gardner Leader LLP, discusses the issues which may affect the purchase of a property that is located in a Radon Affected Area.

Whenever I buy a property on behalf of a client I will undertake a local and an environmental search. One question common to both is whether the property is in a Radon Affected Area.

Not so long ago radon was thought to be a hazard limited to areas of Devon and Cornwall. Now it is known to be present, in varying but frequently hazardous concentrations, over the whole country; and I’m no longer surprised when a search reveals a problem in areas covered by Kennet or Basingstoke and Deane. This growth is inevitable as more data becomes available: the first map of Radon Affected Areas, which was published in 1990, was based on the results of measurements in 8,200 homes, and we now have half a million results for the whole UK.

The danger of radon is that it is a source of radioactivity, which in turn is known to increase the risk of certain types of cancer, notably lung cancer. However, the risk of cancer may be compounded or reduced by a number of factors including preventative measures, lifestyle, diet and pollution, so it is very difficult to determine the risk of radon to an individual in isolation to other factors.

When is the level of Radon considered to be a cause for concern?

Radon is measured in becquerels per cubic metre (Bqm3). The average UK household radon measurement is believed to be 20 Bqm3. Action is recommended when the level exceeds 200 Bqm3. An area is deemed ‘Radon Affected’ if 1% or more of the number of households in the area, which have been tested, exceed the action level. However, the reports that we obtain only reflect averages in an area and are not specific to a particular property.

There is no quick answer to finding out a particular property's risk. It can take several months for the test data to be gathered and several more for it to be analysed. The results of the test can vary considerably based upon the time of year that the test is undertaken and the ventilation in the room affected. Radon levels are known to be capable of reduction by ventilation and tend to be less when weather conditions are warmer.

How will Radon affect my property transaction?

In most new homes constructed after 1988 in Radon Affected Areas, the builders will have fitted additional sub floor ventilation to reduce the levels entering a property. This now forms part of Building Regulations and NHBC. For properties built prior to that date or without suitable sub floor ventilation, remedial works can still be undertaken to reduce the level but inevitably at a financial cost to the owner.

If the result of my searches reveals there may be a problem, I will ask the vendor's conveyancer if the property has been tested for Radon. However, from our experience it is rare that current owner(s) or predecessor(s) have previously commissioned a test.

What is becoming more common is a Radon Bond which is an agreement that is entered into between the purchaser and the seller of a property. It is designed to reduce the financial risk to the purchaser of a property in a Radon Affected Area by giving them time to carry out testing, without delaying the sale. It involves the buyer retaining a small part of the purchase price that can be used towards paying for radon remedial works should they prove necessary after the house has changed hands. The money is usually held by a third party such as a solicitor, and after an agreed period of time, usually a minimum of nine months, any remaining money is returned to the seller. It may be that radon monitoring shows that no remedial works are required, in which case the whole sum is returned to the seller.

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