Radon Verification at a Private School development in Conwy, North Wales
Project Overview
The project comprised a new private school development in Conwy, North Wales, designed to provide education facilities for children aged 4 to 16 and a best-in-class learning facility for over 100 pupils. The site was identified on the UK radon maps as being within a 5-10% radon potential area.
For this level of radon potential, a radon membrane was required and needed to be verified, although sumps and/or ventilation were not required. A proprietary gas membrane, Juta GP1 Gas Membrane, was specified and installed by specialist contractors.
The Challenge
The key challenge was ensuring the radon protection measures were installed correctly, verified before being covered and documented to satisfy Building Control and support planning discharge.
The verification also needed to fit around the site programme, weather delays, access constraints and sequencing between the groundworks contractor, membrane installers and GeoShield verification team.
Approach
GeoShield reviewed the design and specification before preparing a verification plan in line with C735 guidance. The verification plan considered the buildability and detailing of the design, the quality and certification of the specified membrane and the competence of the specialist installation team. On site verification was undertaken by Liam England (TGVP) and Niall Hogan over 16 visits, in line with the pre-agreed plan.
During these visits, all perimeter details, joints, corners and pipe penetrations were inspected and integrity tested. Photographic evidence was captured across all areas. GeoShield coordinated closely with JCW Gas Membranes and the groundworks contractor to ensure protective measures were not covered before inspection and testing. Minor defects were identified, quickly rectified, retested and photographed for inclusion in the verification report. The ongoing verification visits confirmed that the installation was compliant, the planning condition was discharged and the works were accepted by Building Control.
Get in touch
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The verification must be undertaken by an independent third party. This should not be the installer or the membrane manufacturer. BS8485:2015+A1:2019 and CIRIA C735 both provide further information on this
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BS8485:2015+A1:2019 would be the top of the hierarchical list of documents. However, NHBC NF94, CIRIA C735, CIRIA C801 and CIRIA C748 all provide excellent information and guidance.
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From a management perspective, integrity testing should focus on high-risk details, such as service penetrations. These areas account for the majority of future leak-related defects if not properly assessed.
“GeoShield provided prompt guidance, site visits, practical installation advice and detailed inspection reports, while remaining flexible with inspections and thoroughly testing completed membranes onsite.”
C.P
