Flood Risk Assessment to Support a Change of Building Use

Project Outline

Unda was approached by a regular client who was overseeing the development and subsequent change of use of a 3-storey commercial building to residential flats. As the development would lead to people habiting the building on all 3 floors the regulator requested a Flood Risk Assessment as the building was located in flood zone 3 (an area recognised as having a risk of flooding).

Benefit to Client

Unda was able to demonstrate through their Flood Risk Assessment that whilst the development was in flood zone 3 the area was protected by effective and maintained flood defences. Within the report, an evacuation strategy was included. Planning permission was granted.

Unda’s Approach

Unda’s flood risk assessment was prepared to assess the potential significance of flood risk to a development which consisted of a vacant commercial being adapted for residential purposes. The site was located in flood zone 3 as classified by the Environment Agency.

The development’s location was highlighted as being at potential risk of flooding from surface water, river, coastal and reservoir flooding. Unda’s flood risk assessment demonstrated that although the building was located in a flood zone, the area’s defences were suitable to mitigate against potential flooding. Based on being able to quantify whether the mitigation measures in place were adequate, the overall risk rating of low was given to the site within Unda’s completed report.

Unda’s specialist flood risk consultant conducted a detailed review of the data and assessed the on-site and off-site flood risk. The proposed development did not involve changes to the existing building's footprint and concrete car parking area. Unda was able to identify that there would be no increase in impermeable surfaces or loss of floodplain storage within the site boundary following the building’s conversion.

Run-off from the development remained unchanged indicating that there would be no increase of flood risk from the site to any local receptors.

As part of the flood risk assessment, Unda included an escape route should the site become inundated with water in the unlikely event there was a barrier breach.

If you have concerns about flooding issues to a property which you are looking to purchase, sell or secure flood insurance for, please contact Unda. Our flood risk consultants will quickly be able to advise how they can assist and will provide a fixed price quotation to understand your issues and provide solutions where possible. For prompt attention Tel: 01293 214 444.