10.06.16
Improving the flood performance of buildings
Source: PSE Jun/Jul 16
Rosie Harper, programme manager for built environment at BSI, discusses how new flood protection guidance can help local authorities.
Resilience, “the capacity to recover quickly from difficulties”, is a term being used with increasing frequency, and is proving apt in the wake of widespread flooding which has affected the UK in recent years. As such, greater importance is being placed on flood resistance and resilience by both local and national government, and a desire for effective solutions is being sought to an ongoing concern.
While policies do not advocate the building of dwellings in areas with a significant risk of flooding, the current lack of housing, including affordable housing, in the UK could lead to pressures on developing in areas prone to flooding.
In addition, government places priority on the redevelopment of brownfield land and vacant industrial buildings and warehouses, many of which are located in areas with a high probability of flooding.
The BS 85500:2015 ‘Flood resistant and resilient construction – Guide to improving the flood performance of buildings’ plays a precautionary role in this scenario. The standard is based on the DCLG publication, ‘Improving the flood performance of new buildings: Flood resilient construction’. It brings the document up to date, focusing on the flood performance of buildings constructed using modern methods of construction. The standard’s main area of focus is on reducing the impacts of flooding by promoting the use of flood-resistant construction materials and techniques.
In doing so, it also allows for faster recovery of properties following a flood event, saving energy and reducing the potential health risks associated with mould.
Placing flood mitigation higher on local agendas
Earlier this year a coalition of architects, civil engineers, environmental scientists and water experts made an unsuccessful bid to the House of Lords to include flood protection in the Housing and Planning Bill, urging it to restrict the rights of developers to connect new houses to already overloaded existing drainage systems.
The Bill has recently received Royal Assent leaving this issue unresolved. Further calls have been made by the LGA and Property Care Association for changes in building regulations to include mandatory flood protection measures for properties.
BS 85500 can help local authorities and planners place flood mitigation measures higher on their agenda.
Promoting the standard
According to Iain Finnigan, senior engineer policy and flood risk management at Central Bedfordshire Council, communication is key. Therefore talking about BS 85500 to practitioners is vital, and local authority planners and building control officers can help by promoting the standard’s use for sites in flood risk areas to developers, consultants and builders.
For Andrea Kitzberger-Smith, planning policy manager at the London Borough of Richmond upon Thames, there is clear value in using BS 85500: “It sets out a range of mitigation measures that may be appropriate depending on the location and type of development, taking account of the type, depth, duration and frequency of flooding.”
Kitzberger-Smith is keen to add that there are a variety of ways in which the planning system can help addressing flood risk, and BS 85500 provides useful advice for planners and applicants on the selection of resistance and/or resilience measures in relation to the design of flood water depth above ground level.
Support for mandatory change is there and the majority of professionals welcome further advances in new techniques and, importantly, advice on what not to do when considering the range of age-related building construction types for the correct form of repairs and materials.
The cascade of research started within the industry will be vital if genuine progress is to be made in both reducing the flood damage to properties and the recovery time for habitation of buildings.
Some ways BS 85500 can help planners:
- Where a development has to be located in a specific area and where the land use would allow for temporary disruption during times of flood
- In applications for development or redevelopment of an existing property, such as a dwelling, in an area at likelihood of flooding
- Where a change of use of a building is proposed, such as from a less vulnerable use (e.g. café, restaurant, office) to a more vulnerable use (e.g. housing, nursery), where it is not possible to incorporate other flood management measures
- Provides advice on the selection of resistance and/or resilience measures in relation to the design flood water depth above ground level
- Provides guidance on how to make a basement flood resilient and resistant; it also sets out measures on how to retrofit existing basements
- Sets out guidance on how extensions can be constructed to be flood resistant and/or resilient
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