Environment Agency Standing Advice Development and Flood Risk - England

March 2007

Householder and other minor extensions

welcome | user flowchart | consultation matrix | sequential test results table | applicant and agent advice

householder and other minor extensions | general surface water drainage information

planning policy statement 25 | flood risk assessment note 1 | flood risk assessment note 2 | flood risk assessment note 3

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The guidance below is designed to cater for domestic extensions as well as the extension of an existing building used for non-domestic purposes where the footprint created by the development does not exceed 250 square metres.

The Environment Agency recommends that:

Applicants complete the table below and include it with the planning application submission. The table, together with the supporting evidence, will form the Flood Risk Assessment (FRA) and will act as an assurance to the Planning Authority that flood risk issues have been addressed as part of the development.

Planning Authorities check the planning application and ensure that one or other of the mitigation measures proposed in the table below has been incorporated into the development.

Applicant to choose one or other of the flood mitigation measures below.

Applicant to provide the LPA with the supporting Information detailed below as part of their FRA

Applicant to tick one of the boxes below

Either ;

Floor levels within the proposed development will be set no lower than existing levels AND, Flood proofing of the proposed development has been incorporated where appropriate.

Details of any flood resilience and resistance techniques to be included in accordance with ‘Preparing for floods’ (ODPM 2003)

Or;

Floor levels within the extension will be set 300mm above the known or modelled 1% (1 in 100 chance each year) river flood level or 0.5% (1 in 200 chance each year) tidal & coastal flood level.

This must be demonstrated by a plan that shows finished floor levels relative to the known or modelled flood level.

All levels should be stated in relation to Ordnance Datum

Click here for information on flood resilience and resistance techniques

Cumulative impact of minor extensions and the removal of Permitted Development rights.

In circumstances where local knowledge (Strategic Flood Risk Assessment held by the LPA/ letters from the parish council etc.) has indicated that the cumulative impact of minor extensions may have a significant effect on flood risk as highlighted in PPS25 paragraph D14, FRA guidance note 2 can be applied.

End of comment