Radon is a radioactive gas which, when inhaled, can damage the lungs. It comes from the decay of radium in the ground and can enter the house via cracks in the foundation, gaps in floors and walls or through water wells. Exposure to radon is known to cause lung cancer and may also be linked to other health issues. Fortunately there are measures which can be taken to reduce radon levels in homes.

The Norwegian Radiation and Nuclear Safety Authority (DSA) recommends that those who are planning to carry out radon reduction measures engage professional services. A number of firms have specialized in this area and are able to offer advice on the most suitable mitigation measure for your home. You can find a list of these companies on the DSA website. When choosing a firm, contact several and compare offers and prices. Also enquire about the firms’ qualifications and experience.

In general, measures against radon can be divided into two categories; temporary and permanent measures. Temporary measures are intended to help prevent radon entering the building until more permanent measures can be implemented. Permanent measures reduce radon to a safe level in the indoor air.

The most common method to reduce radon in buildings is to install a so-called radon sump, a small cavity about the size of a bucket immediately under the floor slab. This is connected to a pipe work which leads to the outside. This system works by a principle of sub-slab depressurization. Soil gases are drawn out by a fan in the radon sump and vented to the outside, before they can be trapped in your home.

Radon gas can also be reduced by constructing barriers between the soil and the living spaces. These can either be passive or active and are often used in combination with other measures such as sub-slab depressurization. In order to be effective these barriers need to be built in such a way that they do not restrict air flow in other parts of the building and are impermeable to moisture.

If you have tested your home and the radon level is above 4 picocuries per liter (pCi/L), the DSA strongly recommends that you consider remediation measures to reduce radon in your home. The EPA has set this level as an action guideline to protect against radon exposure.

Even if your radon level is below the recommended action guideline, it is still advisable to have it tested again after implementation of mitigation measures. It is possible that the radon level in your home will rise again after the measures have been implemented.

The most important measure against radon is to test your home regularly. The EPA recommends a short-term test that lasts for about 90 days or longer, and a follow up long-term test to better characterize the radon situation in your home. A do-it-yourself test kit is available at many hardware stores. The EPA also provides a listing of radon measurement and mitigation professionals nationwide.