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Building Control


What is it Radon? 

Radon is a naturally occurring radioactive gas which originates from the decay of uranium in rocks and soils. It is colourless, odourless and tasteless and can only be measured using special equipment.  

When radon surfaces in the open air, it is quickly diluted to harmless concentrations, but when it enters an enclosed space, such as a house or other building, it can sometimes accumulate to unacceptably high concentrations. 

It is recommended that long-term exposure to radon concentrations above certain levels be avoided. The Building Regulations require that precautions be taken to avoid danger to health and safety caused by substances in the ground covered by a building. Specific guidance on how to achieve this is given in Technical Guidance Document C. 

The radon levels in County Mayo vary considerably. To see the radon level in your area, visit the Environmental Protection Agency web site and examine the map showing the radon levels throughout Ireland. You can access the map at  

Every new house is required to incorporate some degree of radon preventive measures at the time of construction in accordance with building regulations. The degree of protection required is dependent upon whether the site is located within a High Radon Area. The owner is advised to employ a competent designer and a competent supervisor to ensure the correct level of radon preventive measures are provided and installed correctly. 

Building owners are strongly recommended to have the Radon concentration level assessed when the building is in use and again after remediation action, should such prove necessary.

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