RADON REMEDIATION METHODS PASSIVE METHODS ACTIVE METHODS Barriers Natural airflow Sump systems Reduce pressure Underfloor extraction Sump systems Underfloor ventilation Cellar ventillation Positive pressure fans Raise pressure No fans or pumps

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, remedial measures need to be considered. In this section we will look at the principles behind radon remediation, and the methods used to achieve results.

Radon remediation principles

Radon mitigation / remediation measures can be classified as either Passive (no fan used) or Active (a fan is used). These two principles can be sub-divided in four basic methods for dealing with radon in a property; Barriers, Natural airflow (including passive sumps), reducing the pressure, and raising the pressure.

Passive radon remediation

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

⇒ Find out more about Passive Radon Remediation

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.

⇒ Find out more about Active Radon Remediation

Choosing the right method

To choose your preferred radon protection 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. The radon detector results
  2. The ground floor construction
  3. The 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.
Servicing a radon system

Radon factsheet no.1:

Comparison of radon remediation methods

A guide to the effectiveness of different remediation methods, based on UK Radon Ltd’s experience.

A summary of various remediation measures and some of the parameters to consider when deciding which system is best for your house.

UK radon factsheet 01

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

  • A large property, or one without loft space, may deter your from fitting a positive pressure fan.
  • A property with high condensation may lend itself to the use of a positive pressure system.
  • A large or sprawling property footprint may mean more than one system may have to be fitted.
  • A mixed floor property might need two different types of system to remediate the radon.
  • A flat above ground-floor may only be able to fit a positive pressure system
  • 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 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?