Buying or selling a home in a radon affected area

If you are concerned about buying or selling a home in a radon affected area, UK Radon can help.

Since 2013, as part of any house sale, local council land searches have included a land search for radon. As sellers, you will also be asked if you have measured for radon in your house, and if you have taken any action as a result.

This page aims to help house buyers and sellers to overcome any barriers when the radon land search reveals the house is in a radon affected area – ie there is radon in the 1km square associated with your property.

radon affected area

Local Authority Search (CON 29R) and Property Information (TA6) forms

When buying or selling a property you will come across two forms that may disclose information about radon. They are known as CON29R and TA6.

These forms may be the first time a buyer or seller sees any reference to radon gas, and this may be worrying. UK Radon Ltd have produced this page to help people understand what to do when radon becomes a subject of the buying and selling process, and aims to assist buyers and sellers through the stages required to bring the house transaction to a successful conclusion.

The two stages of buying & selling a home in a radon affected area

There are two stages in buying or selling a home in a radon affected area: 1. Radon testing 2. Finding a solution (should one be required).

Stage 1: Radon testing

If you are planning to sell or buy a property, then it is good practice to go to UK Radon website, managed by Public Health England. Here you can view probability bands for radon on a 1km square map of the UK for free, or you can order a search for £3.90, which will advise if your home should be tested, based on the probability of radon associated with a 25m square.

For sellers: if you find out that your property needs a test then you should consider testing. If after testing, it is 200 Bq m-3 (annual average) or above, consider remedial work – see stage 2.

For buyers: you may find that the property needs a test or has a previous radon test (from the TA6 form). It is advisable to do your own test after moving into the property. Discuss this with your solicitor and consider a radon retention should radon levels be 200 Bq m-3 or above.

A radon test can be done for around £50 or less. The domestic test comprises placing two detectors for 3 months, one in the main living room, and one in the main bedroom.

A 7 day radon test will give you an initial ‘snapshot’ of your levels: low (less than 120Bqm-3, medium (between 120Bqm-3 and 300Bqm-3), or high (above 300Bq m-3) and is not seasonally corrected.

If the measurement is low, it is probable that the 3 month test will be under 200Bq m-3. If it is medium you will be recommended a 3 month test is conducted to make sure of your seasonally corrected value is above 200Bq m-3 action level, and above 300Bqm-3 you may consider you need to undertake remedial work to reduce your radon levels, or consider using a radon bond during your house purchase/sale.

A 3 month radon test provides a seasonally-corrected average which is accepted as a reflection of the property’s annual average radon level. If the level of your 3 month measurement is above 200Bq m-3 then it is advisable to take action to reduce your radon levels.

It should be noted that PHE, in their guidance notes for obtaining a radon report, state that the only way to find out whether a property is actually above or below the Action Level is to carry out a radon measurement.

Stage 2: Find a solution

When radon levels are 200Bqm-3 or above, then consider action to reduce your radon levels. There are two ways in which you can resolve any issues during the sale or purchase of a property. You can undertake remedial action prior to sale, or consider a Radon Retention (sometimes called a Radon Bond).

Radon remediation work

Aim to reduce radon levels as low as possible below 200Bqm-3. A specialist radon contractor can provide a quote for work.

Passive/natural radon remediation (not using a fan) could cost as little as £200, depending on radon levels, location and property type. Typical active (using a fan) radon systems for domestic dwellings could cost between £800 and £1,200 depending on radon levels, location and property type.

Please use our ‘Get A Quote’ link below to get a quote for your property. A radon retest measurement should be conducted after completion of the work, to make sure the radon levels have been reduced.


Radon retention

If you do not wish to go through the process of remediation work, or time limits the completion of the house sale/purchase, then a Radon Retention may be a solution. This is where the buyer and seller agree on a sum of money that is likely to be enough to cover the cost of radon remediation work and associated testing. The money is taken out of the buyer’s purchase price and held by a third party (for example, a solicitor) until any radon remediation work is completed and a radon test result is known. Both parties sign a contract that stipulates how the bond will work, and a period of time for the testing and remediation work can be set (probably between 6 months and a year).

Any testing and remediation work is paid for by the retention money. A suggested figure for a radon retention on a single domestic dwelling would be in the region.

House buying or selling

This fact sheet aims to help house buyers and sellers to overcome any barriers when the radon land search reveals there is radon in yourproperty area (the 1km grid square associated with your property).