Radon and Basement or Ground-Floor Home Gyms: What UKHSA Advises on Testing

Basements, cellars and ground-floor garage conversions are popular sites for home gyms because they offer space, a solid floor and some distance from neighbours. They also sit closest to the ground, which is the main source of radon, a naturally occurring radioactive gas. The UK Health Security Agency (UKHSA) publishes guidance on when and how to test for it. This article summarises that guidance for a home-gym setting. It concerns the UK, and where a source covers only part of it, that is stated.

What radon is

UKradon, the UKHSA’s radon information service, describes radon as a colourless, odourless radioactive gas formed by the radioactive decay of the small amounts of uranium that occur naturally in all rocks and soils. It says the ground is the main source of radon in buildings. Because it cannot be seen or smelled, the only way to know the level in a building is to measure it.

What UKHSA says about the health risk

UKradon states that radon increases the risk of lung cancer, that the higher the radon and the longer the exposure the greater the risk, and that it causes over 1,100 lung cancer deaths each year in the UK. The risk is higher for ex-smokers and significantly greater for current smokers. UKradon explains that radon produces radioactive dust in the air, which is trapped in the airways and emits radiation that damages the lungs. It adds that there is no consistent evidence that radon causes cancers elsewhere in the body.

A UKHSA press release from December 2022 gives the wider context. It says that for most people the risk from radon remains low, that the vast majority of buildings are outside radon “Affected Areas” (areas with higher radon potential), and that UKHSA advises testing a home if you live or work in an Affected Area.

The action levels

UKHSA recommends that radon levels should be reduced in homes where the average is more than 200 becquerels per cubic metre (200 Bq/m3), a recommendation endorsed by the Government. The level refers to the annual average concentration in a home. UKHSA also sets a target level of 100 Bq/m3 as the ideal outcome of remedial work in existing buildings and of protective measures in new buildings. If an assessment falls between the target and action levels, UKradon says action to reduce the level should be considered, especially if there is a smoker or ex-smoker in the home.

Why basements matter for a home gym

UKradon’s guidance on measuring radon includes a specific note for properties with basements: all occupied basements, meaning those used for more than 50 hours per year, should be monitored regardless of radon potential. Fifty hours a year is just under one hour a week, so a basement or cellar gym used regularly would fall well within that description. UKradon also has separate guidance on reducing radon in cellars and basements.

Checking whether an address is in an Affected Area

UKradon offers an address report, which it says will tell you whether a home is in a radon Affected Area. If it is, UKHSA recommends measuring the radon concentration. The radon map, updated for England, Wales and Scotland in December 2022 by UKHSA and the British Geological Survey, is the first update in over ten years. The Northern Ireland map, last updated in 2015, was not changed. The same press release says the map is used in building regulations to inform where radon preventative measures should be incorporated in new buildings.

How a home test works

According to UKradon, a domestic test uses two detectors, one in a living area and one in an occupied bedroom, left in place for three months. The three-month period averages out short-term fluctuations, because radon levels vary from day to day with weather and from room to room. The detectors are safe and simple to use and can sit on a shelf, although heat or submersion in water can damage them and they should not be opened. UKradon says results will be less reliable if:

• the occupier changes during the test;
• the home is unoccupied for more than a few weeks in the three months;
• there are ongoing building works;
• the detectors are not put in place within a week of arriving;
• the test lasts less than three months.

The building-works point matters for anyone converting a room into a gym: a test started during works is less reliable, so testing after they finish, using a validated laboratory as UKradon advises, makes sense.

If the result is high

UKradon says the aim of remedial work is to reduce radon as low as possible, and that several methods exist. Its guidance groups them by floor type and radon level: a radon sump, positive ventilation or under-floor ventilation. It says that simple actions such as sealing around loft hatches, sealing large openings in floors and adding ventilation do not reduce radon levels on their own, though they can help when combined with other effective measures, and that completely sealing floors is difficult and can cause rot in wooden floors. The local council’s environmental health department may offer advice, and for levels above 1,000 Bq/m3 UKHSA suggests contacting it. Tenants are advised by UKHSA to speak to their landlord, who should organise a test.

Frequently asked questions

Do all home gyms need a radon test?

No. UKHSA says the vast majority of buildings are outside Affected Areas. Its guidance is to test if you live or work in one, and that occupied basements should be monitored regardless of radon potential.

The bottom line

Radon comes from the ground, is measurable only by testing and is described by UKHSA as low risk for most people. The guidance is to check whether an address is in an Affected Area and to monitor any occupied basement, which includes a regularly used basement gym. A three-month test with two detectors gives the annual-average picture, and a result above 200 Bq/m3 calls for remedial action.

Sources

• UK Health Security Agency, UKradon, “Radon Action Level and Target Level”
• UK Health Security Agency, UKradon, “Measuring radon”
• UK Health Security Agency, UKradon, “The risks to your health from radon”
• UK Health Security Agency, UKradon, “How to reduce radon levels”
• UK Health Security Agency, “UKHSA and BGS publish updated radon map for Great Britain” (GOV.UK, 2 December 2022)