NHBC’s Land Quality Service (LQS) team started working with Liverpool City Council at the Liverpool Festival Gardens site in May 2020. The project began with two Technical Assessments on this former landfill site with a vision to create a new diverse neighbourhood.
Background:
In 1984 the area was used as part of the UK's first international garden festival which helped give the sizeable 11-hectare site its name.
As the site was also previously used for waste disposal Liverpool City Council looked to engage with NHBC’s LQS team at the very start of the project to minimise uncertainty about whether the site was suitable for future residential development and to support further discussions with development partners.
Finding the Right Solution:
The technical challenges on this site mainly resulted from its use for landfill and included:
- potential long term excessive settlement of the landfill materials
- managing ground gas risks
- and the presence of contamination.
The remediation strategy involved excavation, segregation and processing of the various waste streams to identify suitable materials to be reused as engineered fill.
The reviewed remedial proposals included re-engineering of up to 5.5m of the top of the backfilled materials to produce a development platform suitable for the construction of residential properties.
The site also required controlling the organic carbon content of the fill materials to manage the potential for ground gas generation and to reach agreement on suitable chemical acceptance criteria for the retention or reuse of materials to protect the future occupiers of the site.
The benefits of the NHBC Land Quality Service:
Liverpool City Council’s early engagement with NHBC’s LQS team ensured effective and ongoing collaboration throughout the progression of the project.
Thanks to ongoing communication during the project and visibility of key documents detailing the ongoing aspects throughout the remedial works, the LQS team were able to provide regular feedback. This gave confidence that works would be acceptable for NHBC’s Buildmark warranty and provided reassurance that the proposed foundation approaches would be acceptable.
Securing a Stage 1 to 3 Certificate of Land Quality:
LQS were commissioned for two Technical Assessments in May 2020 ahead of being commissioned for the full Stage 1 to 3 Certificate of Land Quality in July 2020. Earthworks and remediation work began in January 2021 and were completed in the summer of 2023. The final LQS certificate was issued in December 2023.
Chris Ridland, Senior Regeneration Manager at Liverpool City Council said “We are grateful to the LQS team for all their help and advice on this complex project. We look forward to continuing our strong, collaborative working relationship moving forward into the residential design and delivery stage.”
