Radon Testing & Mitigation near you

UKHSA recommends, and the government has endorsed, that radon levels should be reduced in homes where the average is more than 200 becquerels per cubic metre. That is the Action Level, and it is the threshold at which remedial work is recommended rather than optional in any practical sense. It is expressed as an annual average, which is why a measurement has to run long enough to represent a year rather than a week.

The Target Level of 100 becquerels per cubic metre is the second figure and the more useful one when you are commissioning work. UKHSA describes it as the ideal outcome for remediation works in existing buildings and protective measures in new buildings, so a mitigation scheme that gets a house from 400 down to 190 has cleared the Action Level but has not reached the standard the work should be aiming at.

Both figures are about long-term exposure. Radon concentration varies through the day and between rooms, rises when a house is shut up and falls when it is ventilated, so a single short reading is close to meaningless. The measurement protocol exists precisely to average that variation out.

The UK radon maps show the estimated probability of radon levels exceeding the Action Level across an area: the darker the colour, the greater the chance of a higher level, ranging from less than one home in a hundred in white areas to greater than one in three in the darkest. That is a statement about the chance that homes in an area are affected, not a statement about your house. A house in a white area can be above the Action Level and a house in a dark area can be well below it.

An address search is more precise but still probabilistic. A report tells you the estimated probability of being above the Action Level, based on detailed grid data, and it answers one of the standard legal enquiries used on house purchase in England and Wales. Some searches are run on postcode rather than full address, in which case they return the maximum radon potential for any property with that postcode — an indicative worst case rather than a result for your building.

Two caveats matter. The map should not be used for basements, cellars or underground sites, all of which should be treated as having an increased chance of high radon levels regardless of location. And coverage differs across the UK: UKHSA and the British Geological Survey published an updated map for England, Wales and Scotland on 2 December 2022, the first substantial update in over a decade, while the map for Northern Ireland was last updated in 2015 and was not changed by that work.

An active radon sump, fitted with a fan, is the most effective way to reduce indoor radon levels, and it is the first choice where there is a concrete groundbearing slab or a concrete capping to the soil beneath a suspended timber floor. It works by creating a pressure difference beneath the floor so that soil gas is drawn to the sump and exhausted outside rather than being drawn into the house.

Positive house ventilation is the alternative where a sump is impractical. A small quiet fan blows fresh air, usually from the roof space, into the building, diluting the radon already indoors and slightly pressurising the house against further ingress. It is less powerful than an active sump and is generally used where levels are moderately above the Action Level rather than far above it.

Underfloor ventilation applies where there is a suspended timber floor over an open void. Many British homes have exactly that, and improving the natural ventilation of the void — clearing and adding airbricks, removing debris that blocks cross-flow — can reduce concentrations on its own. Where natural ventilation is not enough, a fan is used to blow air into or extract air from the space below the floor. Sump systems are not appropriate for timber floors laid directly over bare earth unless the soil is capped first.

Construction decides the method and the method decides the price. The variables are whether the ground floor is a solid slab, a suspended timber floor over a void or a mixture across the footprint; whether a sump can be formed externally or has to be built inside; how far pipework has to run to reach an acceptable exhaust position; whether there is an existing standby sump that only needs a fan; how many separate areas or extensions the house has; the electrical work needed to supply the fan; and whether more than one sump turns out to be needed. Measurement is a separate and much smaller cost from mitigation.

LokalMatch is the introduction and no more than that. Post the reading you have, the type of ground floor and your postcode, and contractors who do radon work in your area will contact you. Homeowners are never charged; the pros pay for the requests they receive. LokalMatch does not measure radon, does not install anything, does not set prices and does not vet, rank or recommend the businesses that reply, so ask each of them what level they expect to achieve and how that will be verified.