115-117 Derby Road Longeaton
The Brief
RIDA Reports was appointed to deliver a detailed flood risk assessment for 115-117 Derby Road in Long Eaton. The project comprises internal alterations and the installation of new main-road doors to an existing restaurant building.
Why the Client Chose RIDA
Because the property is located in an area with complex flooding mechanisms, the client needed a specialised consultancy to develop a compliant mitigation strategy. RIDA was chosen to ensure the commercial alterations aligned with National Planning Policy Framework (NPPF) standards and to provide the vital evidence required to support the planning application.
The Challenge
Although initially mapped in Flood Zone 3, detailed modelling confirmed the site lies within Flood Zone 2, facing potential fluvial flood depths of up to 850mm. The property is also at high risk of groundwater flooding and a low risk of surface water ponding up to 300mm. A major physical constraint was the inability to raise the existing Finished Floor Level (FFL), meaning the flood hazard could not be avoided simply by elevating the building’s thresholds.
The RIDA Difference
To overcome the fixed FFL and protect against the 850mm fluvial and 300mm surface water risks, RIDA specified a robust ‘water exclusion strategy’ utilising highly flood-resilient construction materials. We explicitly advised against the use of standard plasterboards and wood, recommending materials tested with “Good” resilience ratings.
To manage the high groundwater and fluvial threats, we stipulated that all new services, wiring, and meters must be installed above the predicted flood level, with all service entries sealed using closed-cell insulation. To prevent water ingress at the threshold, we recommended the use of sealed PVC external framed doors. Additionally, we mapped a safe evacuation route along Derby Road and recommended the implementation of a tailored Flood Management and Evacuation Plan.
The Outcome
The comprehensive assessment successfully proved that the restaurant alterations would be safe for their 50 to 100-year design life without increasing off-site flood risks. By providing clear, practical resilience measures to address the site’s specific physical vulnerabilities, the report delivered the robust evidence necessary to satisfy NPPF requirements.
