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Radbar Radon Sump

100% of 100
£40.00 Ex VAT
£48.00 Inc VAT

Collect harmful radon gas so that it can be safely ventilated away with this radon sump. Suitable for active and passive radon sump systems.

Radon Gas Sump

RADBAR Radon Sumps are designed to collect radon gas so that it can be safely ventilated away. They form a key part of Radbar’s gas system, protecting properties and inhabitants from ground gases.

These Radon Gas Sumps work effectively under solid floors and under suspended floors if the ground is covered with concrete or a membrane. In most applications, a standard sized home would need one sump to be installed.

What is a radon sump?

A radon sump is a prefabricated plastic unit that is located in the foundations to collect ground gases like radon. You connect pipework to it in order to control the safe extraction of radon and other potentially harmful ground gases. 

How does a radon sump work?

The Radon sump collects the ground gas. The sump is connected to a venting pipe that passes through the external wall and is brought out above ground level  - it usually travels up the side of the house to roof level. 

There are two methods of removing the radon gas via this venting pipe - a passive sump or an active radon sump. 

Passive Radon Sump

Passive gas sumps are based on the passive principle where air flow is encouraged by differentiation in pressure between inside and outside. Ventilation is often assisted by the presence of air bricks. They are less effective than active sumps, and are therefore best suited to properties with lower radon levels. They work best when the venting pipe ends above the eaves of the roof. Passive radon systems are suitable for radon concentrations that are slightly above the action level (around 200–300 Bq m-3). The main advantages are:

  • no running costs
  • silent running
  • If the sump does not reduce radon levels sufficiently, a fan can be added later.

Active Radon Sump

Powered by an electric fan, an active radon sump is a highly effective way to reduce radon levels. An active system is necessary when high levels of gas are present, in particular when Full Protection is a requirement. You will also need to opt for the active sump in terraced houses when front to back passive ventilation isn’t possible.

How to install a radon sump

Firstly you need to determine how many sumps are required for the property - one sump every 15m radius is recommended. A single radon gas sump is therefore adequate for an average sized home.


You will need to create a small hole in the exterior wall for the venting pipe to exit just below ground level. 110mm is the standard size but you can drill holes as required for wider pipework. A core drill is ideal for creating the hole.

Radon Sump Installation

You need to create a pit in the floor slab for the radon sump to go into. Once in position, you can connect your pipework - 110mm PVC-U pipe - to one outlet of the gas sump. The pipe needs to then be run horizontally and pass through the external wall in the hole you’ve drilled. Terminate the pipe just above ground level and cap it. It should be positioned around 100mm from the face of the external wall. Eventually, the pipe will run up the side of the property to roof level.

Important note: The end of the exhaust pipe should not be near any doors or windows.

Backfill the sump.

By installing a suitable ventilation fan, the sump becomes part of an active radon system. 

Radon sump detail:


Sealing joints 

All joints need to be fully sealed and all pipework gas tight. It’s particularly important to seal the pipe well in the wall,using an approved flexible seal between the pipe and masonry.

Radon Sump System

The radon sump pump system is an essential part of the Radbar radon system in new build projects. The underfloor ventilated radon sump functions within this high quality radon system to protect properties and its inhabitants from ground gases. 

Other Products in Radon System:

The system also consists of a membrane that extends the whole of the floor and walls such as:

  • Amber One
  • Amber Two
  • Hydrocarbon

Permagard - Providing Solutions. Inspiring Confidence

At Permagard, we work hard to provide solutions at affordable prices. The radon sump price delivers great value for exceptional quality. If you have any questions about gas membranes, the necessary accessories or information on how to install radon barrier membranes contact our experts. We provide free technical advice on 0117 982 3282.

Read our guide to installing radon gas systems.


  • Part of the Radbar gas system
  • Robust prefabricated plastic sump unit
  • Easy to install
  • Fits standard 110mm pipework
  • Strategically placed perforations to maximise radon uptake