Radon remediation

Once you have monitored your home/property for radon and the result shows the radon levels are found to be above the radon action level, radon remediation needs to be considered. In this section we will look at the principles behind radon remediation, and the methods used to achieve results.

Passive radon remediation

Passive radon systems do not have fans. They aim to utilise natural processes to achieve results. They therefore generally have lower ongoing costs than active systems.

Active radon remediation

Active radon protection systems have fans. These either draw radon away from a building by lowering the air pressure (extraction) or create an area of higher air pressure that deters it (ventilation). Active methods generally have much greater impact than passive ones.

Choosing the right radon remediation method

To choose your preferred radon remediation method you need some basic information to get started, related to the structure of your property and the radon monitoring results. In particular, you should focus on: 1. Radon detector results 2. Ground floor construction 3. General house size and construction

1. Radon detector results

The most important parameter to examine is the radon monitor/detector results. Different methods have different impacts on radon. By far the best is the sump system, which lowers the pressure under solid floors, but many other methods may be preferable if your property has suspended floors, or the radon levels are less than 500Bqm-3.

⇒ See our radon factsheet no.1 on the publications page

If you have mixed floors, old and new parts to your building, or it is a large building you may need to gather more radon results from particular rooms to determine where best to place a particular remediation method. For example, is the solid floor or the suspended floor of a mixed floor property the particular source of your radon?


2. Ground floor construction

The ground floor construction of a building is a critical parameter when deciding the best remediation method to use. There are different remediation methods that apply to different floor types:

Solid Floors: Floor sealing, Trickle vents, Core vents, Positive pressure systems, passive sump systems, active sump systems.

Suspended Floors: Floor sealing, air brick replacement, Positive pressure fans, Under-floor ventilation systems.

Mixed Floors: Could utilise any of the above systems depending on the particular source of the radon, if a particular source is determined from monitoring.

Radon remediation methods compared


Particular aspects of a house such as its size could affect your choice of radon remediation measure. For example:

  1. A large property, or one without loft space, may deter you from fitting a positive pressure fan.
  2. A property with high condensation may lend itself to the use of a positive pressure system.
  3. A large or sprawling property footprint may mean more than one system may have to be fitted.
  4. A mixed floor property might need two different types of system to remediate the radon.
  5. A flat above ground-floor may only be able to fit a positive pressure system
  6. A property with a cellar may need to focus on remediation measures in the cellar.


You should always test your property for radon after you have radon remediation fitted, to make sure it is having the desired effect. Your installer should always check that the system is functioning correctly before leaving. Have they checked the airflow through the radon system, and the pressure drop in a sump system?

Radon remediation techniques compared

A guide to the effectiveness of different remediation methods, and some of the parameters to consider when deciding which system is best for your house.

A quick guide to radon remediation

Click on any button to find out more