These two approval processes are frequently confused — but they serve entirely different purposes, and you may need both. Here is what each one covers.
"Do I need planning permission?" is one of the first questions clients ask when they begin thinking about a renovation. The honest answer is often: you may need planning permission, you almost certainly need building regulations approval, and these are two completely different things.
The confusion between the two is understandable — both are forms of official approval, both involve the local authority to some degree, and getting either wrong causes problems. But they operate under different legislation, consider different factors, and have different consequences if you ignore them. This guide explains both clearly.
Planning permission
Planning permission controls *what* you build and how it affects the external appearance of your property and the surrounding area. It is granted (or refused) by the local planning authority — your borough council — and its primary concern is land use, visual impact, and the effect on neighbours and the local environment.
Planning permission is generally required when you are:
- —Adding to the volume or footprint of a building — extensions, outbuildings, rear additions
- —Changing the external appearance in a material way — adding dormer windows, rooflights visible from the street, external cladding
- —Changing the use of a building or part of a building — converting commercial to residential, creating a flat within a house
- —Working in a conservation area or on a listed building (where permitted development rights are reduced or removed)
Planning permission is *not* required for most internal works. If you are reconfiguring rooms, opening up a floor plan, renovating a kitchen or bathroom, or making structural changes that do not affect the external envelope, planning permission is generally not needed.
Permitted development
Certain types of development are automatically permitted under the General Permitted Development Order — you can carry them out without applying for planning permission, provided they fall within defined parameters (size, materials, location on the site). These include many single-storey rear extensions, loft conversions within volume limits, and certain outbuildings.
Permitted development rights are reduced or removed in conservation areas, for listed buildings, and where Article 4 Directions have been made. In much of prime central London, permitted development rights are significantly curtailed — in practice, this means planning permission is required for a wider range of works than would be the case in a standard suburban property.
Building regulations
Building regulations control *how* you build — the technical standards to which work must be carried out. They cover structural safety, fire safety, thermal performance, ventilation, electrical safety, drainage, accessibility, and a range of other technical requirements. Building regulations approval is given (or withheld) by the local authority building control department, or by an approved inspector from the private sector.
Building regulations approval is required for most structural and significant building work, including:
- —Extensions of any kind
- —Loft conversions
- —Basement conversions
- —Structural alterations — removing load-bearing walls, installing steel beams, altering foundations
- —New drainage connections
- —Installation of a new bathroom or kitchen that involves drainage work
- —Electrical work that is not classified as minor work
- —Heating system installations
Notably, building regulations apply to a substantial amount of internal work that does not require planning permission. You can freely alter the internal layout of your property without planning permission — but if you are removing a load-bearing wall, you will need building regulations approval for the structural work.
How building regulations approval works
There are two routes: a Full Plans application, which involves submitting detailed drawings and specifications before work starts and receiving approval in advance; and a Building Notice, which allows work to start more quickly but without detailed pre-approval of the design.
For complex projects — particularly those involving structural work, basements, or significant alterations — the Full Plans route is strongly preferable. It gives you certainty that the design is compliant before work starts and protects you if questions are raised later.
Building control inspectors visit the site at key stages — foundation, structure, drainage, insulation, completion — to verify that work complies with the approved plans and the technical standards. A completion certificate is issued when the work is signed off. This document is important: it is required when you sell the property and for insurance purposes.
Retrospective building regulations approval (regularisation) is available for work that was carried out without consent, but it is not a process you want to go through. It is more expensive, less certain, and may require opening up finished work for inspection.
The key differences in practice
| Planning Permission | Building Regulations | |
|---|---|---|
| Controls | *What* you build | *How* you build |
| Concern | Land use, visual impact, neighbours | Structural safety, fire, energy, drainage |
| When required | External changes, changes of use | Most structural and significant building work |
| Internal works | Rarely applies | Often applies |
| Who decides | Local planning authority | Building control (local authority or approved inspector) |
| Consequence of ignoring | Enforcement notice, possible demolition | Safety risk, problems on sale, regularisation cost |
Do you need both?
Frequently, yes. An extension typically requires both planning permission (for the external addition) and building regulations approval (for the structural, thermal, and drainage work involved). Certain internal projects require building regulations only. A change of external appearance that does not involve significant construction work might require planning only.
For listed buildings, a third layer — listed building consent — is also required, as separate from both planning permission and building regulations.
How ASAAN handles approvals
We manage the full approvals process on behalf of our clients as part of our project management service:
- —We assess at the design stage what consents are required
- —We prepare and submit planning applications, including design and access statements where required
- —We appoint building control and manage the inspection and sign-off process
- —We coordinate party wall processes (see our Party Wall Act guide) and listed building consent where applicable
- —We ensure a completion certificate is issued at the end of every project
Our clients do not need to navigate any of this themselves. If you have a project in mind and want to understand what approvals it is likely to require, contact us to discuss it, or view our portfolio to see the range of projects we have delivered.
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