1. Home
  2. Knowledge centre
  3. Radon and Retrofit (PART 1/2)

Why we must take radon seriously in regard to retrofit 


Changing a building from one state to another is not without consequence. After all, it’s moving it from one state to another that saves energy or improves the health and comfort of the building. We are also about to embark on a national programme to retrofit a very large percentage of our homes. 

But there is always the risk of negative outcomes or unintended consequence. It’s why we should assess buildings before we start, have a plan for them and check that, in the end, it worked. It’s ultimately why we have standards.

When we talk about risk, we often talk about the likelihood and the severity of the risk. The World Health Organisation (WHO) has categorised radon as a carcinogen, in the same group as asbestos and tobacco smoke. In Ireland, approximately 300 cases of lung cancer each year are linked to exposure to radon.

Research suggests that some of the retrofitting measures could have an impact on radon levels, for better or worse.


What is radon?

high radon areas ireland


Radon is a radioactive gas. It is formed in the ground by the radioactive decay of uranium which is present in all rocks and soils.

You cannot see it, smell it or taste it

It can only be measured with special detectors.

Outside radon is diluted to very low levels. Radon can enter a home from the ground through small cracks in floors and through gaps around pipes or

cables. Homes in some parts of the country are more likely to have a radon problem. These parts of Ireland are called high radon areas. You can check interactive maps to see whether your home is in a high radon area.

The EPA has a great website with all the information you need to know: www.radon.ie 



The only way to know how much radon is in a home is to test


lung cancer radioactive gas

The radon map may give you an indication, but the truth is, you can’t stand in a house in a street and predict what the radon is likely to be unless you have the results of a radon test.

The acceptable level, or Reference Level, for homes in Ireland is 200 becquerel per cubic metre (Bq/m3) or less.

In short

You can’t see it, smell it or taste it. In fact, the only way you know whether radon levels in a home are above 200 Bq/m3 is to test. Radon increases the risk of lung cancer over many years of exposure. For smokers, that risk is 25 times greater as there is a synergistic effect between radon and tobacco smoke.





So how do we reduce the risks and maximise the benefits?


Fortunately, there is a large body of evidence that we can draw on, and several further studies are underway, to identify those retrofit measures that may increase radon levels. Other measures, notably improved ventilation and sealing the floor slab, have been shown to reduce radon levels. Plus, their impact can be very beneficial to homeowners in delivering energy savings and in reducing indoor radon levels.

Whilst we can risk assess certain types of properties and certain types of retrofit measures in advance, the best way to ensure radon levels are reduced during retrofitting is to have before and after radon measurements in each individual house or apartment. This will confirm the impact of all of the retrofit measures in aggregate and give occupiers peace of mind. 

How much are tests?

At the moment the cost for an individual test is around 50 Euro. In the context of a deep retrofit even at a cost optimal level of say 20-30k, I think it is a good investment. 


Retrofit works can have a negative or positive impact on radon levels, depending on the initial building characteristics and the type of retrofit work carried out. It is therefore important to understand the building from the perspective of radon access pathways and how sealing the ground floor to improve airtightness and improving the ventilation can contribute to creating an overall radon-safe retrofit. These measures can also contribute to energy savings, so with proper planning, both health and energy saving benefits can be delivered.

In Part 2, see three risk pathways for buildings based on a simple assessment and test before work is agreed (which could be a short-term test, not less than 1 month)


>PART 2: Managing the Radon risk, a proposal

Post a question

Your email address will not be published. Required fields are marked *