Radon Mitigation: Essential Paperwork and Testing Records

Radon is a naturally occurring radioactive gas formed by the decay of small amounts of uranium in rocks and soils. It is odourless, colourless, and undetectable without specialist equipment. In certain parts of the UK—particularly areas with granite or limestone geology such as Devon, Cornwall, the Peak District, Northamptonshire, and parts of Wales and Scotland—radon levels inside buildings can accumulate above recommended safety thresholds. When property owners take action to reduce indoor radon levels, keeping a clear paper trail is just as important as installing the equipment correctly.

Understanding Radon Testing Reports and Action Levels

Radon is measured in becquerels per cubic metre of air (Bq/m³). In the UK, the target level for domestic properties is 100 Bq/m³, while the formal Action Level is 200 Bq/m³. If a property records an annual average level at or above the Action Level, public health guidance advises installing a remediation system to reduce concentrations.

Standard testing is typically carried out using passive track-etch detectors placed in key living spaces (usually a ground-floor living room and an occupied bedroom) for a period of three months. Once analysed by an accredited laboratory or the UK Health Security Agency (UKHSA), homeowners receive a formal validation report. This report is your baseline evidence. You should always keep the original test certificate showing the test dates, detector locations, seasonal correction calculations, and final measured concentration.

Key Records for Different Mitigation Systems

Radon mitigation techniques vary depending on property construction, foundation type, and recorded gas concentrations. Whether you have an active mechanical system or passive barrier work, you need comprehensive records from the specialist contractor who designed and installed the solution.

• Initial diagnostic report: Site survey notes, pressure tests, or diagnostic drill-hole readings used to determine the best remediation route.
• System layout and specification: Drawings showing the exact location of radon sumps, sub-floor pipework, external exhaust discharge points, or Positive Input Ventilation (PIV) units.
• Electrical safety certificates: A Minor Electrical Installation Works Certificate or Part P Building Regulations compliance certificate for any dedicated power supply, fused spur, or external fan unit.
• Manufacturer documentation: Operating manuals, technical data sheets, and equipment warranties for extraction fans, positive pressure fans, and control modules.
• Post-mitigation re-test results: Follow-up validation test reports completed after the system has been running, demonstrating that radon concentrations have dropped below the Action Level.

Ongoing Maintenance and Servicing Logs

Radon mitigation is rarely a fit-and-forget undertaking. Active systems rely on mechanical components that run continuously to depressurise the ground beneath the slab or gently pressurise the indoor living space. Extraction fans contain bearings that wear out over time, and positive ventilation systems use air filters that clog with dust and debris.

Keep a simple log of routine maintenance. For positive pressure systems, record the date and filter grade every time you inspect or replace the intake filter (typically every two to five years depending on the manufacturer). For active radon sumps, record annual visual inspections, check that external exhaust terminals remain unobstructed by garden growth, and document any pressure gauge or airflow indicator readings. If a fan unit is serviced, repaired, or replaced, retain the invoice and the updated guarantee on file.

Why Buyers and Conveyancers Need These Records

During a property transaction, standard local authority and environmental searches indicate whether a property sits within a designated Radon Affected Area. Furthermore, the Law Society's Property Information Form (TA6) specifically asks sellers whether a radon test has been carried out, what the results were, and whether any remediation system has been installed.

If you disclose that a radon fan or sump is present but cannot produce the paperwork, buyers and their mortgage lenders may become hesitant. They will want reassurance that the system was installed by a competent specialist, that it complies with electrical standards, and that follow-up tests confirmed its efficacy. Having your initial test, installation paperwork, subsequent validation certificates, and maintenance log organised in one place resolves enquiries quickly and prevents unnecessary transaction delays.

Organising Your Property Records Digitally

Paper test certificates and manufacturer booklets often get misplaced over the years, especially when equipment runs silently in an attic or against an outside wall. Storing these records on an independent record-keeping platform like Project Passport ensures that diagnostic reports, laboratory test results, electrical sign-offs, and filter service dates remain securely attached to your property's history.

By maintaining an orderly digital archive, you protect both the day-to-day health of your household and the long-term transparency of your home when the time comes to sell.