Handbook of Radon.
11. How to decide on radon remedial treatment.
1. Don't panic. Any radon problem can be solved.
2. Don't spend money in haste. Tackling a radon problem sensibly and calmly will result in a satisfactory outcome with minimum inconvenience and cost.
3. Don't believe all you read or hear about radon. As in most subjects, there is a wide range of misinformation to tempt the unwary.
4. Remember that not all houses are the same. Small houses are often quite simple to cure. Larger houses, especially those built on different levels and with parts dating from different periods can require expert attention to obtain the best results.
5. Remember that not all radon measurements are the same. Different rooms often have very different radon levels, even in small houses. Detailed interpretation is sometimes essential.
There are many factors that in real buildings can determine the best type and location of a radon system. By way of introduction, it is helpful to reflect on why and how radon enters houses. This occurs primarily as a result of slight pressure differences between the air inside the building and the air underground. A principal driving force is the buoyancy of warm air indoors when it is cooler outdoors. In theory, if a house or other building is completely sealed, then no warm air can leak out and no cold air from outdoors or the ground can enter, except via diffusion.
Radon will enter through any crack or gap and especially through large holes in floors and (sometimes) walls. Some houses have well sealed concrete floors, others have leaky timber floors, sometimes with decayed joists, and some have a mixture of floor types. Window designs also vary widely, as do heating systems. Little advice has been issued on draught-proofing of floors. Indeed, the aim of most draught-proofing appears to be to seal doors and windows as much as possible, so keeping 'fresh air' out of buildings! Sealing of floors can result in a dramatic decrease in indoor radon levels, but success is uncertain.
How a house is ventilated can be important because it may make a difference of at least a factor of two in annual average indoor radon levels. This may be sufficient to bring many (indeed, most) 'affected' houses below the so-called action level, but a corresponding number of houses classed as 'safe' on the basis of routine screening measurements could of course have their radon levels increased to above the action level by altered ventilation habits. Sometimes sealing windows can REDUCE indoor radon levels!
No reasonable amount of extra ventilation will 'cure' a house that has been assessed at several thousand Bq/m3, but it may be all that is required in many other cases, and in some houses is necessary to help cure condensation and other problems that have been caused in part by excessive draught-proofing.
In summary, the interactions between house temperature, ventilation, and occupant behaviour, and house design, can influence not only radon entry rates, but selection of remedial measures.
The key factors determining choice of remedial measures include
The annual average radon level. This is important because building work that may be justified at 5000 Bq/m3 may represent a gross overreaction at 400 Bq/m3. Some high-level houses can be cured quite cheaply.
Whether any member of the family smokes, and how long the family intends to live in the house. Both these factors determine the extra risk that will be incurred by continuing to live with an elevated radon level. For non-smokers the calculated risks are not great in all but the worst affected UK homes, at least for a few years. Availability of funds for remedial works. Often there is merit in undertaking simple measures first, followed later (if necessary) by more expensive steps. The design of the house. In large houses of mixed construction especially, some care can be needed to achieve a satisfactory and aesthetically acceptable solution at reasonable cost, and without excessive disruption.Future scientific developments may produce novel ways of reducing the dose from radon daughters.
Advice is also contained in Part 3 of this Handbook. Amongst the relevant Sections are:
41. Avoiding undue risk: time-scales for radon remediation.
52. Design & operation of radon sump systems.
53. Who to employ to cure a radon problem: a local
builder, a specialist company or a consultant?
56. The role of heating systems in determining radon levels.
57. Influence of radon measures on timber floors.
58. Sealing techniques and their performance.
59. Diagnostics for radon remediation.
60. Experience with radon sumps.
61. Experience with whole house pressurisation.
62. Experience with ventilation provision.