Under requirement C3 of the building regulation 1997 all reasonable precautions must be taken to avoid the dangers of radon gas entering houses.
Radon preventative measures must be applied in the construction of new dwellings or long stay residential buildings. There are Two levels of protection against radon, a basic or precautionary level which applies to new buildings in all parts of the country and a more advanced level which applies to new buildings in designated high Radon Areas.
High Radon Areas are areas where it is predicted that more than 10% of the houses have radon concentrations above the Reference Level.
For all parts of the country, whether in high or low area the Building Regulations require that new buildings include a potential means of reducing radon levels.
In the case of dwellings of normal construction, this is most commonly achieved by means of a radon sump, as described in the Department of the Environment's publication "Radon in Buildings".
The Radiological Protection Institute of Ireland recommends that, once occupied, all new buildings should be tested for radon and If the radon level is found to be above the Reference Level then the radon sump, or other means of reducing the radon levels, should be activated.
In High Radon Areas, the Building Regulations require that, as well as a sump other addittional measures should be taken like a fully sealed low-permeability membrane .