Flood Risk Assessment — First Floor Change of Use to a Gym in Flood Zone 2, Leicester
We prepared a site-specific Flood Risk Assessment for the change of use of the first floor of a commercial building at 48-50 Rolleston Street, Leicester, LE5 3ST, to Use Class E(d) as a gym — a Flood Zone 2 site in the River Soar and Willow Brook catchment — on behalf of Michelle Hill of Simple Planning Solutions. Fluvial risk is medium, consistent with the Flood Zone 2 designation, surface water risk is high, sewer risk is medium on a combined network, and groundwater and artificial-source risk are low. The proposal involves no external alterations, no new floorspace and no below-ground works, and E(d) is Less Vulnerable development, appropriate in Flood Zone 2 without the Exception Test. The assessment demonstrated an acceptable level of flood risk by virtue of elevation above the modelled flood levels, without reliance on additional mitigation.
Flood Risk Assessment for a First Floor Change of Use to a Gym in Flood Zone 2, Leicester
Location: 48-50 Rolleston Street, Leicester, LE5 3ST | Client: Michelle Hill, Simple Planning Solutions | Services: Flood Risk Assessment
Elevation Does the Work
The proposal is the change of use of the first floor of an existing commercial building to Use Class E(d) (indoor sport, recreation and fitness) as a gym, with no external alterations, no new floorspace and no below-ground works. We were appointed by Michelle Hill of Simple Planning Solutions to prepare the site-specific Flood Risk Assessment required to support it under application 20261080.
The defining feature of the assessment is that the development is at first floor and nothing else about the building changes. There are no external alterations, no new floorspace, no below-ground works and no change to the drainage arrangement or the impermeable area.
That combination produces a conclusion that is unusual to state plainly but entirely correct here: the proposed first floor development is at an acceptable level of flood risk for its lifetime by virtue of its elevation well above the modelled flood levels, without reliance on additional mitigation. The measures set out in the report are recommended as good practice for the building as a whole, rather than as a condition of the development's safety.
Saying so explicitly matters. The alternative, specifying flood resistance measures for a first floor gym because the site sits in Flood Zone 2, would add cost to the scheme without adding safety, and would obscure the fact that the real residual risk at this building sits at ground floor, where the proposal makes no change at all.
Site Characteristics and Flood Risk Profile
Rolleston Street lies in the North Evington area of Leicester, in an established mixed commercial and residential setting within the River Soar and Willow Brook catchment.
We drew on the Environment Agency Flood Map for Planning, the Risk of Flooding from Rivers and the Sea and Risk of Flooding from Surface Water datasets, BGS geological mapping, sewer flooding records for the postcode sector and the Leicester City Council Strategic Flood Risk Assessment. The site lies within Flood Zone 2.
Fluvial risk is medium, consistent with the Flood Zone 2 designation: the site falls within the 1-in-1000-year extent but outside the 1-in-100-year extent.
Surface water risk is high. This is the governing source at ground level, reflecting the dense urban fabric, the extent of impermeable surfacing across the surrounding streets, and modelled overland flow in the vicinity. It is the reason the report addresses the building as a whole rather than confining itself to the first floor.
Sewer flooding risk is medium, reflecting recorded incidents in the surrounding postcode sector on a combined network. Groundwater risk is low, with a low likelihood of groundwater emergence recorded at the site. Risk from artificial sources is low.
Vulnerability, Access and Egress
Use Class E(d) is Less Vulnerable development, which is appropriate in Flood Zone 2 without the Exception Test. The change of use does not increase the vulnerability classification of the building.
The report addresses safe access and egress in the round. Occupants of a first floor gym are above the modelled flood level, so the practical consideration is not depth within the premises but the route between the building and the highway during a surface water event, together with the warning arrangements that would allow the premises to close in advance of one.
Outcome
The FRA demonstrated that the change of use is at an acceptable level of flood risk for its lifetime and that flood risk at the site and at surrounding sites is not increased. Leicester City Council was provided with an assessment that separates what the development actually does from what the site's flood zone might suggest, and that recommends good practice for the building without imposing it as a condition on a proposal that does not require it.