Building Control Explained: Full Plans vs Building Notice
Planning permission gets most of the attention in conversations about home renovation and extension projects — but Building Control is just as important, and often less well understood. They are separate regulatory systems, and you need to engage with both. This post explains what Building Control does, the two main routes available to you, and why your choice between them matters.
What Is Building Control?
Building Control enforces the Building Regulations 2010 (SI 2010/2214) — a set of technical standards that set minimum requirements for the design and construction of buildings. These cover structural safety (Approved Document A), fire safety (B), waterproofing (C), drainage (H), ventilation (F), energy efficiency (L), and numerous other aspects of how a building must perform.
Building Regulations apply regardless of whether planning permission is required. You can build a rear extension entirely under permitted development — no planning application needed — and still require Building Regulations approval. The two regimes operate independently.
Building Control approval is normally required for any new extension, loft conversion, structural alteration, new bathroom, or significant electrical or plumbing work. A building inspector from the relevant authority (or an approved private body) visits the site at key stages to inspect that work complies before it is covered up.
Route 1: Full Plans Application
A Full Plans application involves submitting detailed drawings and specifications to the Building Control body before any work starts. These are checked against the Approved Documents and either approved, approved with conditions, or rejected. Once approved, you receive formal notice that your plans comply.
During construction, inspections take place at prescribed stages — typically: foundation excavation, oversite preparation (before concrete is poured), damp-proof course level, structural frame, pre-plaster first-fix, thermal insulation, and final completion. You notify Building Control before each stage so an inspector can attend.
At the end of the project, when all inspections have been passed and the work is complete, Building Control issues a Completion Certificate. This document is important: your conveyancer and your mortgage lender will ask for it when you come to sell or remortgage.
For any extension, loft conversion, or structural alteration, Full Plans is almost always the recommended route. The upfront plan-check catches design issues before they become expensive problems on site, and the Completion Certificate provides clean evidence of compliance.
Route 2: Building Notice
A Building Notice allows you to give 48 hours' notice to Building Control and start work without submitting drawings for approval. The inspector attends as works proceed and advises on compliance in real time.
This approach is simpler administratively, and can suit smaller or more straightforward works — a new shower room in an existing bathroom, for instance, or minor internal alterations. However, it carries significant limitations.
With a Building Notice, no drawings are formally approved. This means there is no Completion Certificate issued at the end of works. For larger projects — extensions and loft conversions especially — the absence of a Completion Certificate can cause real difficulties on sale. Solicitors acting for buyers or mortgage lenders will ask whether Building Regulations approval was obtained, and the absence of a certificate can require retrospective regularisation or indemnity insurance to resolve.
Regularisation: The Retrospective Route
If work has been carried out without Building Regulations approval — whether through oversight or deliberate omission — you can apply for a Regularisation Certificate. This is a retrospective application to demonstrate that the work, as built, complies with the regulations in force at the time it was carried out.
Regularisation is more involved than a standard application. Building Control may require opening up of finished surfaces to inspect concealed work. In some cases, remedial works are required before a certificate can be issued. It is always better to obtain approval at the right time.
Registered Building Control Approvers
Building Control services are not exclusively delivered by local authorities. Since reforms to the building safety framework following the Building Safety Act 2022, private firms known as Registered Building Control Approvers (formerly Approved Inspectors) can also provide Building Control services for certain project types. Your contractor or architect may have a preference or existing relationship with a particular provider.
Competent Person Schemes
For certain specific categories of work, tradespeople registered under Competent Person Schemes can self-certify their own work — removing the need for a separate Building Control application for that element. Examples include window and door replacement (FENSA scheme), electrical work (NAPIT or ELECSA registered electricians), and gas installations (Gas Safe Register). If your contractor is registered under the appropriate scheme, they will provide you with a certificate that stands in place of a Building Control notification.
Why the Completion Certificate Matters
It is worth being direct about this: if you carry out notifiable works and do not obtain a Completion Certificate, you are creating a problem for your future self. On sale, solicitors' enquiries will surface the gap. Resolution options exist — retrospective regularisation or indemnity insurance — but they cost time and money and can delay completions. Obtaining proper Building Control approval from the outset is not a bureaucratic nicety; it is a practical asset.
RCB Design & Build and Building Control
At RCB Design & Build, managing the Building Control process is part of our role as principal contractor. We manage the notifications, coordinate stage inspections, and ensure the project reaches a clean Completion Certificate without you needing to navigate the process yourself.
To discuss a project in London, contact us at contact@rcbgroup.co.uk or call +44 7359 872594.