Building Notice vs Full Plans: Which Building Regulations Route to Choose

Building Regulations approval is required for most structural building work carried out on a dwelling in England. Common domestic projects requiring Building Regulations approval include:

Always notifiable: extensions (any size or type); loft conversions creating a new habitable room; internal structural alterations (removing or modifying a load-bearing wall); garage conversions; basement conversions; roof alterations that change the structure; new or replacement windows and doors (if not FENSA registered); new bathrooms or shower rooms; replacement boilers and heating systems; electrical installations in kitchens, bathrooms, and external locations (or any new circuit in the rest of the dwelling); and solar panel installations on a roof.

Exempt from Building Regulations: most garden outbuildings under 30m² that are more than 1m from the boundary; small single-storey conservatories attached to the dwelling and below a certain size; and minor repairs like replacing a like-for-like roof tile.

Permitted development status is irrelevant to Building Regulations: a project can be permitted development (not requiring planning permission) but still require Building Regulations approval. These are two completely separate regulatory systems. The most common misunderstanding is that a PD extension does not need Building Regulations — it does.

Competent Person Schemes: some types of work can be self-certified by registered contractors under Competent Person Schemes, without a separate Building Control application. Examples include: FENSA-registered window and door installations; Gas Safe registered gas installations; NICEIC or NAPIT-registered electrical work (within scope). The contractor issues a certificate directly to the homeowner (and notifies the local authority), and no separate Building Control application is required.

The Full Plans procedure is the standard Building Regulations application route for all significant building work.

What you submit: a completed application form, a full fee, and a set of drawings and specifications that demonstrate compliance with all relevant parts of Building Regulations. For an extension, this typically includes: existing and proposed floor plans; elevations; sections; and specification notes covering foundations, structure, insulation, drainage, fire safety, and any other applicable Parts.

Review period: the Building Control officer (BCO) has 5 weeks to check the plans and issue a decision (this can be extended to 8 weeks by agreement). The BCO will either approve the plans, approve them with conditions, or reject them with reasons. If plans are rejected, they are usually resubmitted with amendments.

Benefit of Full Plans: once approved, you have certainty that the design meets Building Regulations before you commit to construction costs. If a BCO later raises an issue during inspection, there is a clear audit trail showing what was agreed. Full Plans approval also provides protection if the work is later sold — the purchaser's solicitor can see that the works were approved.

Site inspections: even after Full Plans approval, the BCO carries out site inspections during construction to verify that the work is being carried out in accordance with the approved plans. Typical inspection stages for an extension: commencement (to check foundations before concrete is poured); frame/structure; insulation; pre-drylining; drainage (before backfilling); and completion (final inspection to issue the Building Regulations Completion Certificate).

Full Plans applications from architects: where a professional architect has prepared the drawings and specification, the drawings are usually submitted as part of the Full Plans application before work starts, making this the natural route for projects where design professionals are involved.

A Building Notice (BN) is a simplified notification to Building Control that allows work to start without prior approval of detailed drawings.

How it works: you submit a Building Notice form and pay the BN fee to the local authority (or notify an Approved Inspector). You must give at least 48 hours notice before work starts. No drawings are required at the notification stage — however, the Building Control officer may request drawings, calculations, or specifications at any stage during or after the work.

Site inspections: the BCO carries out site inspections during construction, the same as for Full Plans. The key difference is that with a BN, the compliance of the work is assessed at inspection — if the BCO raises an issue, the work may need to be altered or opened up to show compliance. There is no pre-approved set of drawings to reference.

Risk with Building Notice: the risk of using a Building Notice is that compliance issues are identified during or after construction, rather than before it starts. If the BCO finds a problem (inadequate foundation depth, incorrect fire door specification, non-compliant drainage) the work must be corrected — which can mean opening up completed work. This risk falls on the homeowner.

Completion Certificate: a Completion Certificate is issued after the final inspection confirms the work complies with Building Regulations. For Full Plans applications, the Completion Certificate is issued against the approved drawings. For Building Notice applications, the Completion Certificate is issued against the BCO's inspection record — there are no approved drawings to reference. Some conveyancers and mortgage lenders are less comfortable with BN completions than Full Plans completions for this reason.

When a Building Notice is appropriate: a Building Notice is appropriate for clearly defined, straightforward work where the compliance position is unambiguous — for example, a boiler replacement or a new internal partition (no structural implications). It is not appropriate for extensions, loft conversions, or any project involving structural work, fire safety requirements, or complex drainage.

Building Control can be provided by either the local authority Building Control team or by an Approved Inspector (AI) — a private sector Building Control body. Both are authorised to carry out Building Control functions under the Building Act 1984.

Approved Inspectors for residential projects: AIs have become increasingly common for residential extensions and loft conversions in London. They typically offer: faster response times than local authority Building Control; a single point of contact (a named inspector for the project); and competitive fees.

The Initial Notice: when using an Approved Inspector, an Initial Notice (IN) is submitted to the local authority, informing them that the AI will be providing Building Control for the project. The AI then issues a Plans Certificate (equivalent to Full Plans approval) and carries out site inspections.

Fee comparison: Approved Inspector fees for residential projects are often comparable to local authority Building Control fees, and sometimes lower. The Building Control fee also covers the cost of all required inspections for the project (unlike some trade contractor quotes where inspections are charged separately).

Mandatory Reporting: Approved Inspectors have a duty to report serious non-compliance to the local authority if the developer fails to rectify a breach of Building Regulations. This provides a backstop enforcement mechanism.

Since April 2024: the Building Safety Act 2022 made significant changes to the Building Control profession. All Building Control Bodies (local authority and private) must now be registered and meet professional competence requirements. The regulatory framework for Approved Inspectors has been subsumed into the new Registered Building Control Approver (RBCA) framework.

If building work has been carried out without Building Regulations approval (or without the required inspections), it is possible to seek retrospective approval via the Regularisation procedure.

When Regularisation is needed: retrospective Building Regulations approval is commonly needed when: a homeowner discovers that a previous owner carried out work without Building Control; or a homeowner carried out work themselves without notifying Building Control. It often comes to light during the sale of the property, when the purchaser's solicitor requests Building Regulations certificates for any notifiable work.

The Regularisation process: a Regularisation application is submitted to the local authority (not Approved Inspectors — only local authority Building Control can issue Regularisation Certificates). The BCO assesses the work and determines whether it complies with the Building Regulations that were in force at the time the work was carried out. If inspection is needed, the BCO may require sections of the work to be opened up (for example, exposing a foundation, opening a floor to check drainage, or opening a ceiling to check structural elements).

Cost: Regularisation applications carry a fee that is typically 120–150% of the standard Full Plans fee (because of the additional inspector time required). If the work is found to be non-compliant, remediation work must be carried out and the Regularisation Certificate will only be issued once compliance is achieved.

Indemnity insurance: in some cases (particularly on property sales) an indemnity insurance policy can be obtained to cover the risk that a local authority might take enforcement action against building works carried out without Building Regulations approval. This is typically used for older, minor works where the enforcement risk is low and a Regularisation Certificate is either not available or not cost-effective to obtain.