Handbook of Radon.
32. Buying or selling a house in a radon affected area.
Radon is unlikely ever to be a widespread concern in sale and purchase of houses in the UK. The reasons include the small scale of the problem, especially compared with that in other countries.
It is acknowledged that short term radon measurements may be misleading, and in any case can easily be 'defeated' by increased house ventilation or similar devious behaviour. A cheap yet reliable measurement may be difficult to obtain during conveyancing.
It is simply unrealistic to place a plaque on the wall of a UK house '257 Bq/m3' or '675 Bq/m3'. Change of occupancy or heating system, choice of a different room for the tests, installation of new windows, etc. could all result in a change in measured level.
New houses, approved for construction after 1988 in radon affected areas have had to incorporate membranes and other measures potentially useful for radon protection. Some of these houses are now appearing on the market, and with the simple claim that they are 'radon proofed'.
Unfortunately this is no guarantee of low radon levels. All it means is that the house was built with measures required by the Building Regulations. The author was in charge of much of the research work and may be consulted.
In the USA, there are differences in house design, and in house-sale formalities. These have encouraged the use, in a few States, of radon tests during house sales. Many houses in the northern States have basements, thus permitting a radon test that is less affected by either weather or occupant actions. However, there are problems in translating these results into meaningful values for the main living spaces. Difficulties have arisen also when measurements have been made using charcoal canisters.
A pervasive influence has been that of house relocation companies who, unlike Estate Agents in the UK, purchase unwanted houses for resale. It is standard practice to require certificates for plumbing, termites, etc., and with the aim of handing them to subsequent buyers. These certificates can be used to transfer liability for problems.
Despite the uncertainties of short-term radon testing, remedial works and certification as a condition of sale have become routine in some areas, and sometimes applied to houses that are unremarkable in their radon levels.
Some enthusiasts in local authorities and radon companies in the UK have advocated a public register of houses above the so-called 'action level', seemingly oblivious of measurement inaccuracies and of the fact that naturally ventilated houses can exhibit variable average levels. If logically a register of radon-affected houses were to be thought appropriate on grounds of Public Health and Safety, then so might a register for substandard electrical wiring and fixed kitchen appliances, both known life hazards to children as well as to adults. Again, a sense of perspective may be recommended. Some legal points are discussed in Section 38.
KEY FACTS:
Radon levels in UK houses are not fixed. Houses sold as 'radon proofed' may have high radon levels, as may any other house.
Annual average radon levels in moderately affected houses can vary by factors of 2, and by 5 or even 10 over short periods in different rooms. Much of the variation may be owing to building and occupant response to weather and other influences.
Elevated radon levels can be reduced, just as dry rot can be eliminated. However, there are many possible remedial techniques, and sometimes the choice is not straightforward, see Section 11.