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Design Guide: Heritage Impact Assessments

Despite what many people think, a Heritage Impact Assessment (HIA) is often a necessity. Also known as a heritage statement and a historic building impact assessment, this documentation plays a pivotal part in how to get approved for planning permission for your listed home.

A HIA is commonly required as part of the regulatory process for development projects, especially when those projects involve areas with known or potential cultural heritage significance. They are crucial for determining the impact of a proposed development on cultural heritage resources, including listed buildings.

HIAs involve a collaboration between heritage experts, archaeologists, and developers to ensure that an impact assessment is accurate and comprehensive. Once compiled, the assessment is reviewed as part of the planning application process and is used to inform communities, stakeholders, heritage advocacy groups, and cultural organisations.

In this blog, we take a look at the reasons why you need a HIA and how to go about obtaining one. We also answer some commonly asked questions about HIAs and the possible repercussions if you go ahead with work without this documentation.

What Is a Heritage Statment?

Heritage statements can form part of a planning application or be created as a separate document to support an application. They are used to explain the significance of a historical building and the effect that the proposed changes you wish to make may have on the fabric of the heritage asset that your building is.

It is also used to justify works being carried out to designated heritage assets. A heritage statement is a very important document that if written incorrectly or is deemed not informative enough, could result in not being granted listed building consent.

What is Classed As A Heritage Asset?

The National Planning Policy Framework (NPPF) states that:

“A building, monument, site, place, area, or landscape identified as having a degree of significance meriting consideration in planning decisions, because of its heritage interest. It includes designated heritage assets and assets identified by the local planning authority (including local listing).”

Heritage assets fall into many categories ranging from World Heritage sites to grade-listed buildings and other types of conservation areas.

Are Heritage Impact Assessments Required for a Planning Application?

You will need an HIA for any listed building consent application. HIAs are conducted in line with legal and policy frameworks related to cultural heritage preservation. This involves works spanning an extension to any works that may impact a non-designated heritage asset.

Below, we have put together considerations to help you to understand more about the need for a heritage statement.

Local planning policies – The first step in understanding the need for a HIA is to review the local planning policies in place. You can do this by consulting with your local planning authority.

The scale of the project – If you are planning a larger and more complex development, the likelihood of needing an HIA increases.

Archaeological interest – Where there is archaeological interest in the area, an archaeological assessment may be required. This will often form part of a heritage impact statement.

Local authority requests – Some planning authorities explicitly request a heritage statement as part of the planning application documentation. This often applies where heritage assets may be affected.

Why (and When) Do You Need a Heritage Impact Assessment?

As mentioned, an HIA is required in situations where a proposed development project has the potential to impact the local cultural heritage. There are many reasons why you need an HIA, we have listed the most common reasons below:

Preservation of Cultural Heritage

The preservation of cultural heritage is extremely important to local authorities. Designated heritage assets include historic buildings, archaeological sites, landscapes, and any other areas with historical or cultural significance. Your local council can make you aware of whether your listed building is located within a conservation area or you can review the Historic England website for more information.

Legal and Regulatory Requirements

There are many regulations and planning policies in place within a local council that mandate the assessment of potential impacts on cultural heritage. An impact assessment ultimately helps to identify where a conservation area or historic assets will be impacted by a project, compliance with regulations is a legal requirement.

Planning Consent Requirements

To obtain planning permission you may need to submit a HIA as a part of your planning application. HIAs assist with the decision-making process and can ultimately help to streamline the process for planning applications.

Mitigation of Adverse Impacts

If potential adverse impacts are identified, the HIA proposes mitigation measures to minimise harm to cultural heritage resources. These measures may include alterations to the project design, preservation strategies, or other protective actions.

What Should Be Included in a Heritage Impact Assessment?

The NPPF states that:

“In determining applications, local planning authorities should require an applicant to describe the significance of any heritage assets affected, including any contribution made by their setting. The level of detail should be proportionate to the assets’ importance and no more than is sufficient to understand the potential impact of the proposal on their significance. As a minimum, the relevant historic environment record should have been consulted and the heritage assets accessed using appropriate expertise where necessary.”

A well-written HIA needs to be concise and should clearly outline the mitigation efforts for changes that you propose. Several components should be included in a HIA. We have included details as to what should be included in Heritage Impact Assessments.

Introduction – A HIA needs a clear introduction that outlines the purpose of the project and the need for assessment. Details about the project that spans its size, complexity, location, and the nature of the proposed development. Include any additional background information that elaborates on the historical and contextual elements. This should also include known information about potential cultural and heritage assets.

Heritage Asset Significance – A clear assessment of the significance of identified heritage resources based on age, rarity, architectural value, and cultural importance should be outlined. The more detail that you add to this section and assess significance, the more helpful your HIA will be.

Potential Impact – You will need to include details of the potential impact of your proposed project as part of your HIA. Consider the direct impacts, visual impacts, and any other factors that may affect the cultural heritage of the local area. You should also be mindful of mitigation measures which you will put into place to offset and avoid potential adverse impacts. This could include design modifications and other planning decisions which the authority is likely to favour.

Who is Responsible for Writing a Heritage Impact Assessment?

The responsibility for conducting and writing a Heritage Impact Assessment is tasked to a heritage professional, archaeologist, or consultant with expertise in cultural heritage. Heritage impact assessments are complex and require a deep knowledge of conservation. As outlined above, many elements are considered for a heritage impact assessment, including site investigation, assessment of significance, mitigation strategies, report preparation, and more.

Heritage Impact Statement VS Heritage Impact Assessments

A Heritage Impact Statement (HIS) is a different piece of documentation from a Heritage Impact Assessment. An HIS presents the findings of an HIA and is submitted as part of a planning application. Its purpose is to inform decision-makers, inclusive of planning authorities, as to the impact a development could have on historical and cultural assets.

Christopher David Design Can Help

Our team of dedicated architectural designers can help you with the process of Heritage Impact Assessments. We have helped many clients over the years to protect their heritage assets whilst making desired changes to their listed buildings or historical land. Contact us today to find out more information about how we can assist.

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