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Heritage Impact Assessments

When is a Heritage Impact Assessment needed? 

Since the Planning (Listed Buildings and Conservation Areas) Act 1990, owners must conduct a Heritage Impact Assessment before making any changes to listed buildings.

Planning Policy Statement 5 states that:
HE6.1 Local planning authorities should require an applicant to provide a description of the significance of the heritage assets affected and the contribution of their setting to that significance. The level of detail should be proportionate to the importance of the heritage asset and no more than is sufficient to understand the potential impact of the proposal on the significance of the heritage asset.                                                                                     As a minimum the relevant historic environment record should have been consulted and the heritage assets themselves should have been assessed using appropriate expertise where necessary given the application’s impact.                                   Where an application site includes, or is considered to have the potential to include, heritage assets with archaeological interest, local planning authorities should require developers to submit an appropriate desk-based assessment and, where desk-based research is insufficient to properly assess the interest, a field evaluation.

HE6.2 This information together with an assessment of the impact of the proposal should be set out in the application (within the design and access statement when this is required) as part of the explanation of the design concept. It should detail the 
sources that have been considered and the expertise that has been consulted.

HE6.3 Local planning authorities should not validate applications where the extent of the impact of the proposal on the significance of any heritage assets affected cannot adequately be understood from the application and supporting documents.  

Heritage Impact Assessments will always be required for the following: 

• Listed building consent applications
• Planning permission applications for sites within the setting of a listed building
• Planning permission applications for sites in conservation areas
• Planning permission applications for sites within the setting of a scheduled ancient monument
• Planning permission applications for sites within registered parks and gardens
• Advertising consent applications on listed buildings or buildings in conservation areas
Assessments are also recommended for:
• Applications that directly affect a non-designated heritage asset or its setting. (Non-designated heritage assets are buildings, structures or sites (including archaeological) that may have a heritage value.)

You will still need a Heritage Impact Assessment even if you have a 'Design and Access Statement' when works are directly proposed to a heritage asset or its setting. The Heritage 
Impact Assessment may form part of the Design and Access Statement but the Design  and Access Statement is not a substitute for it. 

Why is a Heritage Impact Assessment needed?

Understanding the significance of an historic building, complex or area (the ‘asset’) and  the possible impact of the proposed scheme on this significance is the key to good conservation practice. Good information, available from the outset, can speed up the processing of applications, reduce costs and lead to better overall design. 

If the significance of a site has been clearly understood from the outset (based on how the site has changed through time and what survives today), then both the applicant and the District Planning Authority can better understand the impact of the proposal and seek to minimise the impact of the proposal on that significance. Therefore it is important to understand the significance of a heritage asset when considering proposals to alter, demolish or extend the asset or develop within its setting. An early understanding of the significance will inform the direction of an application and help provide a clear and convincing justification of the proposal (as required by paragraph 132 of the NPPF). 

The level of detail in the assessment will depend on the heritage asset and the extent of  the proposal. The Heritage Impact Assessment should be written by a competent person.

Our fees for preparing a Heritage Impact Assessment range from from £250.00 to £800.00 and is entirly related to the complexity of the Assessment.


British Standard BS 7913:2013 contains numerous references to ‘competence’ in that surveys should be “Carried out by competent persons with knowledge of traditional materials, construction techniques and decay processes”. This experience can’t be gained by attending an in-house three day course. It goes on to say “Unbiased advice from competent persons based on best practice should be sought…