Biodiversity Net Gain
1 May 2024

Understanding BNG Exemptions for Small Sites: What Developers Need to Know

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Biodiversity Net Gain (BNG) is a key aspect of sustainable development, ensuring that new projects contribute to biodiversity and natural habitats. However, not all sites are subject to the BNG requirement. If you’re a small-scale developer, understanding the exemptions from BNG is crucial. This blog post will walk you through the types of small sites that are exempt, how to qualify for the exemptions, and when the Small Sites Metric can be used.

Key Exemptions for Small Sites

The following exemptions are pertinent to small-scale developments:

1. De Minimis Exemption

This exemption applies to developments that have minimal impact on habitats. To qualify:

  • The development must not impact a priority habitat.
  • It must impact less than 25 square metres (e.g., 5m by 5m) of on-site habitat.
  • It must impact less than 5 metres of linear habitats, like hedgerows.

If you believe your project qualifies for this exemption, you’ll need to state this in your planning application form and provide reasons and evidence to support your claim. This evidence can include:

  • A description of the development.
  • Existing and proposed site plans.
  • The size of the development in square metres.

It’s important to remember that the local planning authority will evaluate your claim at the validation stage. They will carefully consider if your proposal genuinely qualifies for the exemption, especially for substantive building works or developments with significant areas of on-site habitat.

2. Householder Development

Developments subject to a householder application as defined in Article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015 are exempt from BNG. This typically includes extensions, garden structures, and other small-scale residential projects.

3. Self-Build and Custom Build Development

If you’re building for yourself or custom-building, you could be exempt if:

  • The development has no more than 9 dwellings.
  • The site is no larger than 0.5 hectares.
  • It consists exclusively of self-build or custom housebuilding as defined by the Self-build and Custom Housebuilding Act 2015. The legal definition is an individual or group of individuals who want to build the property and live in them as homes.

When Can the Small Sites Metric Be Used?

In some cases, the Small Sites Metric (SSM) can be used instead of the main BNG metric. The SSM is designed for small-scale developments, offering a simplified approach to measuring biodiversity impact. It can be used when:

  • Residential development has between 1 and 9 dwellings on a site 1 hectare or less.
  • Commercial development has less than 1,000 square metres of floor space or a total site area of less than 1 hectare.
  • The development does not involve mineral winning or working, or waste development.

However, you should use the SSM only when:

  • No high or very high distinctiveness habitats are present on-site.
  • No statutory protected sites are within a 500m buffer.
  • No European Protected Species (EPS) development licences are required.

What to Do If You’re Uncertain What is Needed on Your Scheme

If you are not sure what is required on your scheme, you are advised to get in touch with the planning case officer in the Local Authority and ask them what approach to BNG will be needed on your site. You should also ask them about other ecological requirements for the scheme, in particular:

  • BNG Thresholds and Targets: Learn about the minimum net gain percentage required for your scheme. While the standard is often set at 10%, some Local Authorities may have different expectations.
  • Mitigation Hierarchy: Find out if your project needs to follow a specific mitigation hierarchy (avoidance, minimisation, restoration, offsetting), and understand how it will impact your development plans.

Consider Other Ecological Requirements

Beyond BNG, there may be other ecological requirements that apply to your scheme. The planning case officer can help you understand what these are, so be sure to ask:

  • Protected Species and Habitats: Are there any protected species or habitats on or near your site? If so, you may need additional surveys or specific mitigation measures.
  • Conservation Areas and Special Sites: Determine if your site is within or near a conservation area, a Site of Special Scientific Interest (SSSI), Special Area of Conservation (SAC), or another protected site. This can influence what you’re allowed to do.
  • Additional Permits and Consents: Find out if there are additional permits or consents needed for your scheme, such as those related to tree preservation orders or water management.

Final Thoughts

Understanding BNG exemptions for small sites can save you time and resources during the planning process. If your project qualifies for an exemption or can use the Small Sites Metric, be sure to gather the required evidence and submit a comprehensive application. This way, you’ll increase your chances of approval without the need for complex BNG compliance.

Remember, while exemptions offer flexibility, the goal of BNG is to ensure sustainable development that benefits the environment. Even if your site is exempt, consider incorporating eco-friendly practices into your project to contribute to the broader sustainability goals.

Contact us on 02920 650 331 or enquiries@acerecology.co.uk for further information.

Further information can be found at:

https://www.gov.uk/guidance/biodiversity-net-gain-exempt-developments