Planning permission and building regulations approval are not the same thing. They are two entirely separate legal systems, administered separately, applied for separately, and enforced separately. Planning permission is concerned with whether a development is appropriate in its location. Building regulations are concerned with whether the work is structurally sound, safe, and energy-efficient. Many projects require both. Assuming one covers the other is one of the most common and costly mistakes homeowners make.
What Planning Permission Actually Controls
Planning permission exists to manage how land and buildings are used and developed. Without it, anyone could build anything anywhere, regardless of the effect on neighbours, road safety, or the wider area. The local planning authority assesses each application against national planning policy and local development plans.
What it scrutinises is largely about the proposal’s relationship to its surroundings. That means the siting and scale of a building, its height relative to neighbouring properties, the percentage of a plot it occupies, and its external appearance: materials, brickwork, roof tiles, window proportions. It also takes in landscaping considerations, highway access, and the impact that the development would have on the general environment.
Key things planning permission addresses:
- The location, siting, height and footprint of new buildings or extensions
- External appearance, including materials and how they match existing structures
- Landscaping considerations and the effect on the street scene
- Highway access and any traffic implications
- The impact on neighbours’ daylight, privacy, and outlook
- Effects on the general environment, including trees and drainage
Planning applications for householder projects, such as an extension or loft conversion, are typically decided within eight weeks. That clock only starts once a valid application is submitted, so factor in the time needed to prepare drawings and supporting documents. Expect the full process to run considerably longer than eight weeks end-to-end.
What Building Regulations Actually Control
Where planning permission looks outward at a proposal’s effect on the surrounding area, building regulations look inward at the technical quality of the construction itself. They set legal minimum standards for the design and construction of buildings to protect the health and safety of people in and around them. They apply whether or not planning permission is required.
Building control approval is administered by building control bodies, either your local authority’s building control team or an approved inspector from the private sector. They check both the submitted plans and the actual work on site, at key stages, against the requirements of the regulations.
Building regulations cover a broad range of technical standards:
- Structural stability of walls, floors, and roofs
- Fire safety, including means of escape and fire-resistant construction
- Thermal efficiency and energy performance
- Sound insulation between dwellings and between rooms
- Drainage, sanitary pipework, and damp-proofing
- Safe staircase design, balustrade heights, and headroom
- Electrical installation design, inspection, and testing
- Access and the impact on usability for people with disabilities
Failing to get building control approval is a legal offence. The building control body can require you to open up finished work for inspection, or even require you to demolish and rebuild it. More practically, you will have no completion certificate, and that will cause problems when you come to sell.
When You Need One, the Other, or Both
This is where confusion is most common, and where the cost of getting it wrong is highest. The table below sets out the typical positions.
| Scenario | Planning Permission | Building Regulations |
|---|---|---|
| Large rear extension | Usually required | Yes |
| Small single-storey rear extension (within PD limits) | Not required | Yes |
| Loft conversion | Often permitted development | Yes |
| New garage (detached) | Often permitted development | Depends on size and use |
| Internal remodel, no structural work | Not required | Unlikely |
| Internal remodel with structural changes | Not required | Yes |
| Change of use (e.g. office to residential) | Yes | Yes |
| New dwelling | Yes | Yes |
Permitted Development Rights allow certain types of building work to proceed without a planning application. But permitted development is not an exemption from building regulations. The two systems operate independently. A rear extension that falls comfortably within permitted development limits still requires building control approval before work starts.
It is also worth knowing that permitted development rights can be removed. Properties in national parks, Areas of Outstanding Natural Beauty, and World Heritage Sites have restricted rights. Flats and maisonettes do not benefit from the standard householder permitted development rights at all. If you are unsure whether your property’s permitted development rights are intact, check with your local planning authority before assuming you do not need to apply.
For loft conversions specifically, both approvals are typically needed. The loft conversion process involves structural alterations, new staircases, and fire safety measures, all of which are squarely within building regulations territory, regardless of whether planning permission is needed.
Listed Buildings and Conservation Areas
If your property is a listed building, the rules are stricter still. Listed building consent is a third, separate form of approval, distinct from both planning permission and building regulations. It is required for any works that would affect the character of the listed building, internally or externally, and that includes alterations that would ordinarily be considered minor.
Permitted development rights do not apply to listed buildings. You will need listed building consent, and in many cases planning permission as well, before any building work begins. The conservation officer at your local council is the right starting point. They can advise on what is likely to be acceptable and what conditions might be attached to any consent. Secondary glazing on listed buildings is a good example of the kind of alteration that requires specialist advice before proceeding.
Properties in conservation areas also face tighter controls than standard residential properties. Permitted development rights are either removed or restricted, and the local planning authority will apply greater scrutiny to the external appearance of any proposal, including materials and how they sit within the character of the area.
The Consequences of Getting It Wrong
Skipping either approval is not a minor administrative oversight. It is a legal breach with real-world consequences.
On the planning side, the local planning authority can issue an enforcement notice requiring you to reverse any unauthorised works. Historically, enforcement action for new dwellings or building work completed without permission had to begin within four years. Recent reforms under the Levelling Up and Regeneration Act 2023 are changing those limitation periods, so the window for enforcement is shifting. Do not assume time passing means you are safe.
On the building regulations side, the consequences are more immediate. The building control body can require you to expose completed work for inspection, or instruct you to put right anything that does not comply. You will not receive a completion certificate. Without one, conveyancers acting for buyers will flag the gap during a sale, and the transaction can stall. Retrospective building regulations approval, sometimes called a regularisation certificate, is possible in some cases, but it is more expensive and less certain than doing it correctly from the start.
For anyone buying or selling a property where work has been carried out, the party wall and related approval process is another area where missing documentation creates problems at the point of sale.
Quick Reference Summary
| Planning Permission | Building Regulations | |
|---|---|---|
| What it covers | Land use, appearance, impact on surroundings | Structural safety, fire, energy, drainage, access |
| Who decides | Local planning authority | Local authority building control or approved inspector |
| When applied for | Before work starts | Before work starts (plans) and during construction |
| Typical timescale | 8 weeks minimum | Ongoing through construction |
| Applies to listed buildings | Yes, plus listed building consent | Yes |
| Permitted development exemption | Yes, in some cases | No |
| Proof of compliance | Decision notice | Completion certificate |
| Risk of non-compliance | Enforcement notice, demolition order | Prosecution, remedial works, no completion certificate |
Next Steps
If you are planning any building work, start by establishing which approvals apply before instructing a contractor. Your local planning authority’s pre-application advice service can tell you whether planning permission is needed and flag any constraints specific to your property. For building regulations, contact either your local authority building control team or an approved inspector early, so plans can be checked before work begins rather than after problems emerge on site.
If the property involved is listed or sits within a conservation area, speak to your council’s conservation officer before making any formal applications. The sequence matters: applying for the wrong thing first, or in the wrong order, adds delay and cost.
For a detailed breakdown of what building a new home from scratch involves in terms of costs and approvals, the guide to building a house in the UK covers both sides of the regulatory picture alongside the financial planning involved.
Frequently Asked Questions
In most cases involving structural building work, yes. Planning permission covers the appearance and impact of a development on its surroundings, while building regulations approval covers the technical and safety standards of the construction itself. The two are separate applications and one does not replace the other.
No. Permitted development rights only remove the need for a planning application. Building regulations still apply regardless of whether planning permission is required. You must notify your local authority building control team or an approved inspector before work begins.
You could be prosecuted and fined. The building control body can also require you to open up or undo completed work at your own expense. Without a completion certificate, you will face difficulties when selling the property, as conveyancers and mortgage lenders will flag the missing documentation.
Often yes. Listed building consent is required for any works affecting the character of the listed building, but if the works also constitute development in planning terms, a separate planning application is needed too. Permitted development rights do not apply to listed buildings, so you cannot rely on them to bypass either requirement.
Most householder applications, such as extensions or loft conversions, are decided within eight weeks of a valid application being submitted. The full process typically takes longer once you account for the time needed to prepare drawings and supporting documents before submission.