The Scope: Why the Building Safety Act Affects Domestic Homeowners
A major misconception among UK homeowners and small builders is that the Building Safety Act 2022 only regulates high-rise buildings (over 18 metres or 7 storeys).
On 1 October 2023, secondary legislation—the Building Regulations etc. (Amendment) (England) Regulations 2023 (SI 2023/1162)—inserted a completely new 'Part 2A: Dutyholders and Competence' directly into the Building Regulations 2010.
These dutyholder rules apply universally to EVERY construction project that requires building control approval, ranging from a simple chimney breast removal or knock-through rear kitchen extension to a full double-storey extension or new build.
| Dutyholder Role | Statutory Definition | Who Fulfills This on a Home Extension? | Primary Legal Obligation |
|---|---|---|---|
| Client (Domestic) | Person for whom a building project is carried out for home use | The Homeowner | Must ensure suitable arrangements are made to manage project |
| Principal Designer | Designer in control of the pre-construction design phase | Lead Architect, Architectural Technologist, or Structural Engineer | Plan, manage, and monitor design compliance with all Building Regs |
| Principal Contractor | Contractor in control of the construction phase | Main Building Contractor or Builder | Plan, manage, and monitor building work to ensure physical compliance |
| Building Control Body | Local Authority Building Control (LABC) or Registered Building Control Approver (RBCA) | Council or Approved Inspector | Inspects and verifies statutory compliance declarations before certificate |
The Domestic Client Rule: Automatic Transfer of Responsibilities
Under Regulation 11E of the amended regulations, domestic clients (homeowners commissioning works for their own residence) are legally distinguished from commercial clients:
• Homeowners are not expected to be construction experts. Therefore, if a homeowner does not execute a written contract appointing a specific Principal Designer, the law automatically assigns the role to the lead designer in control of the design phase (usually your architect, architectural technician, or design-and-build company).
• Similarly, if no Principal Contractor is appointed in writing, the builder in control of the construction phase automatically assumes the role by statutory default.
• Competence Requirements: Anyone acting as Principal Designer must possess verified skills, knowledge, experience, and behaviours (SKEB) to ensure compliance with Parts A through S of the Building Regulations.
The Final Sign-Off: Regulation 16D Compliance Notices
The critical procedural change that impacts project completion occurs upon finishing the physical build:
• Joint Statutory Declarations: Under Regulation 16D, the client, Principal Designer, and Principal Contractor must all sign and date a formal Notice of Completion delivered to the Building Control body.
• Legal Confirmation: The Principal Designer must explicitly certify that the design complied with all relevant functional requirements of the Building Regulations, and the Principal Contractor must certify that the works were constructed in accordance with those plans.
• Certificate Gate: Building Control is statutorily prohibited from issuing the final Building Regulations Completion Certificate until all executed declarations are received. Without this certificate, solicitors cannot clear buyer enquiries when you sell the property.
If you purchase a property that had structural alterations, an extension, or a loft conversion carried out after October 2023, your conveyancer must verify that the Completion Certificate specifically references compliance with the Part 2A dutyholder regime.