UK Building Regulations 2010 Regulation 28: Consequential Improvements Guide

Key Takeaways

• Regulation 28 applies to existing buildings with a total useful floor area over 1,000m2 (August 2026).
• It mandates consequential energy performance improvements when specific building work occurs, such as an extension or new fixed building services (August 2026).
• Required work must ensure compliance with Part L of Schedule 1 (August 2026).
• Improvements are only mandatory if they are technically, functionally, and economically feasible (August 2026).

What is Regulation 28 of the UK Building Regulations 2010?

Regulation 28 of The Building Regulations 2010 (S.I. 2010 No. 2214) mandates consequential improvements to the energy performance of certain existing buildings. This regulation requires that when specific building work is undertaken, additional work must be carried out to ensure the building's energy performance meets current standards (August 2026). This applies to existing buildings with a total useful floor area over 1,000m2 (August 2026).

We checked the official legislation on 23 August 2026. The regulation is titled "Consequential improvements to energy performance" and is part of "PART 6" of The Building Regulations 2010.

Which Buildings and Works Trigger Regulation 28?

Regulation 28 applies to existing buildings that have a total useful floor area over 1,000m2 (August 2026). The regulation is triggered when the proposed building work includes:

• An extension.
• The initial provision of any fixed building services.
• An increase to the installed capacity of any fixed building services.

If your building meets these criteria and you are planning such work, you must consider the consequential improvements required. This is a statutory limitation outlined in the legislation (August 2026).

What are the Compliance Obligations under Regulation 28?

Where Regulation 28 applies, the building work must include any necessary measures to ensure the building complies with the requirements of Part L of Schedule 1 (August 2026). Part L sets out the energy efficiency standards for buildings.

However, there is a key exemption: you are not required to carry out work if it is not technically, functionally, and economically feasible (August 2026). This means that while the regulation aims to improve energy performance, it acknowledges practical limitations. You should assess these feasibility aspects carefully before proceeding with any work.

For further guidance on Part L, you can refer to our guide on UK Building Regulations Part L Regulation 26 Target CO2 Solar Guide.

Understanding Regulation 29: Energy Performance Certificates

Regulation 29 of The Building Regulations 2010 focuses on Energy Performance Certificates (EPCs). This regulation, titled "Energy performance certificates", requires that after the completion of work subject to Regulation 28, an EPC must be issued.

The person carrying out the work must:

• Give an energy performance certificate for the building to the owner of the building.
• Give notice to the local authority that this has been done.

This must be completed not more than five days (August 2026) after the completion of the work. This deadline ensures that the energy performance assessment is promptly documented and provided to the building owner and relevant authorities.

For commercial properties, understanding EPC compliance is crucial. Our UK MEEs Commercial Solar PV and EPC Compliance Guide provides additional context.

Navigating Compliance and Feasibility

The application of Regulation 28 requires careful consideration of its scope and the feasibility tests. The regulation does not demand improvements at any cost; the "technically, functionally and economically feasible" clause provides a critical filter. You must document your assessments of these factors.

When planning extensions or fixed building service installations in commercial properties over 1,000m2 (August 2026), you should:

1. Identify if Regulation 28 applies: Check your building's total useful floor area and the nature of the proposed work.
2. Assess Part L compliance: Determine what improvements are necessary to meet Part L of Schedule 1 (August 2026) standards.
3. Conduct feasibility studies: Evaluate the technical, functional, and economic viability of these improvements.
4. Plan for EPC delivery: Ensure an Energy Performance Certificate is prepared and submitted within five days (August 2026) of work completion.

For self-certification processes related to building work, our UK Building Regulations 2010 Regulation 20 Self-Certification Guide offers relevant information. If you are considering solar installations as part of your energy performance improvements, our solar sizing tool can help estimate system requirements.

The market for building services and energy efficiency upgrades can be complex. We advise you to consult with qualified professionals to ensure full compliance with these regulations. We have not verified specific costs for compliance work, as these vary significantly by project and contractor.