Heritage impact assessments

The purpose and importance of heritage impact assessments

In support of a planning application for a range of developments there is often a requirement from the Local Planning Authority for an archaeological Heritage Impact Assessment. 

In order to comply with the advice set out in Paragraph 128 of the National Planning Policy Framework (NPPF) applicants are required to provide a description of the significance of a heritage asset and/or its setting and, importantly, to provide sufficient information in the Heritage Impact Assessment for the Local Planning Authority to understand the impact of the proposals on the significance of any heritage assets affected.

The significance of a heritage asset whether it is a historic building or a buried archaeological site is defined as the value of the asset to this and future generations based upon its heritage interest which may be archaeological, architectural, aesthetic or historic.

The setting of an asset

The setting of a heritage asset is the surroundings in which a heritage asset is experienced and whilst setting itself is not defined as a heritage asset it can make an important contribution to the significance of the heritage asset (Historic England, GPA 3 2015).

For example, the parks and gardens surrounding a grand country house or the surroundings of listed buildings in a conservation area.

A Heritage Impact Assessment is required for any application that directly affects a heritage asset’s significance and its setting and will always be required for applications which affect designated heritage assets.

These include the following categories of application:

  • Listed Building Consent;
  • development attached to a listed building;
  • development within the setting of a listed building;
  • development inside or within the setting of a Conservation Area;
  • development within the setting of a Scheduled Monument and
  • demolition in a Conservation Area.

It is also the case that a Heritage Impact Assessment may be required when an application directly affects a non-designated heritage asset or its setting.

Normally non-designated heritage assets comprise buildings, structures or archaeological sites that have not been statutorily designated but have a heritage value.

Appropriate and proportionate

NPPF paragraph 128 stipulates that the level of information provided in a Heritage Impact Assessment should be appropriate and proportionate to the significance of the heritage asset and the potential impact of the proposal upon that significance.

For example, an application that requires the substantial demolition of a heritage asset would need an in-depth examination and understanding of the heritage asset and of the impact of the demolition on the asset and its setting.

However, an application for more minor works to a heritage asset is only likely to require detailed information on the affected part of the asset and the impact upon it with only a brief assessment of how the impact would affect the significance of the asset as whole.

Further information

Why a Heritage Impact Assessment should be robust »