Don’t play with radon!

Our house, built into a slope and on a rock seam, also lies within a medium-high radon risk area, according to PHE/UKradon. A while back, I applied to UKradon for a home testing kit, which comprised three dosimeters: one for each floor. When the results came back in from the laboratory, some of my fears were confirmed. Ideally, levels should be below 100 (Bq/m³), but not exceed 200.

Our results were as follows:

  • Bedroom (top floor): 37
  • Living Room (ground floor): 85
  • Kitchen/diner: 290!

I suspected the source to be ground radon. The kitchen/diner and extension is built on a new slab with a gas-proof barrier (see earlier post). But, the undercroft beneath the original house simply has a concrete slurry cap (nominal 4in thick) poured on top of the subsoil – I believe the radon is permeating through this cap. The section below has been highlighted to show the suspected radon source (red):

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