Planning Permission vs. Permitted Development: A Plain-English Guide for UK Homeowners

If you're planning to extend your home, build a garden room, or convert your loft, one of the first questions you'll face is: do I need planning permission? The answer is almost always "it depends" — which isn't especially helpful when you're trying to decide whether to spend £200 on a planning application or just get on with the build.

This guide cuts through the jargon and explains the difference between planning permission and permitted development rights, what you can and can't do under each, and how to protect yourself if you're unsure.

What Is Planning Permission?

Planning permission is formal consent from your local council to carry out development or make a change of use to land or buildings. When people think of "getting planning permission," this is what they mean: submitting an application, waiting 8 weeks (or longer), and hoping the planning officer approves it.

Applications are considered against the local development plan and national planning policy. Factors like the impact on neighbours, design quality, traffic, and the character of the area all play a role. Permission can be granted with conditions, refused, or referred to committee if controversial.

In England, a full householder planning application costs £258 (from December 2023). In Wales it's £232. Scotland and Northern Ireland have their own fee structures. If refused, you can appeal — but the process takes months and there's no guarantee of success.

What Is Permitted Development?

Permitted development (PD) rights are a set of national rules that allow certain types of work to be carried out without needing to apply for planning permission. They're essentially a pre-granted permission that Parliament has decided is generally acceptable, provided specific criteria are met.

Permitted development rights exist for householders (Class A through H under the Town and Country Planning (General Permitted Development) Order 2015 as amended), covering extensions, loft conversions, outbuildings, roof alterations, and more.

The critical thing to understand is that PD rights come with conditions and limitations. Just because something is "permitted development in principle" doesn't mean your specific project qualifies. Size limits, height restrictions, proximity to boundaries, and material requirements all apply.

When Permitted Development Rights Don't Apply

PD rights are removed or restricted in certain circumstances:

• Conservation areas — many types of work require full planning permission in designated conservation areas, including cladding, certain extensions, and outbuildings visible from a public highway.
• Listed buildings — if your home is listed, virtually all external alterations (and many internal ones) require listed building consent, regardless of PD rights.
• Article 4 Directions — councils can issue Article 4 Directions that remove specific PD rights in particular areas, often to protect the character of Victorian terraces or other sensitive areas. Check with your local planning authority.
• New-build homes — some developers restrict PD rights on new estates via conditions attached to the original planning consent. Check your title deeds.
• Flats and maisonettes — householder PD rights apply only to houses. If you live in a flat or maisonette, virtually all external alterations require planning permission.

Common Projects: Permission or Not?

Single-Storey Rear Extensions

Under PD rights, you can build a single-storey rear extension up to 4m deep on a detached house, or 3m deep on any other type of house (semi-detached, terraced). The extension cannot exceed 4m in height (3m if within 2m of a boundary). Materials must be "similar in appearance" to the existing house.

There is also a "prior approval" scheme under Class A of the GPDO that allows extensions up to 8m deep on detached houses (6m for others), but these require a neighbour consultation before proceeding. You apply to the council — it's not full planning permission, but it's not purely PD either. Most councils process these within 42 days.

Loft Conversions

Loft conversions with a dormer are generally permitted development provided the volume added doesn't exceed 50 cubic metres for a detached or semi-detached house (40m³ for terraces). Dormers on the principal elevation (the front of the house, usually facing the street) are not permitted development and require full planning permission.

Hip-to-gable conversions fall under PD provided volume limits aren't exceeded. Mansard roofs almost always require permission.

Outbuildings and Garden Rooms

An outbuilding (shed, garden room, home office, pool house) is permitted development provided it is:

• Single storey with a maximum eaves height of 2.5m and maximum overall height of 4m (3m within 2m of a boundary)
• Not forward of the principal elevation
• Not covering more than 50% of the total garden area (including existing outbuildings)
• Not within the curtilage of a listed building

Driveways and Hardstanding

Paving the front garden for a driveway requires planning permission unless the surface is permeable (gravel, permeable block paving, etc.) or water drains to a lawn or garden area rather than the street. This rule was introduced in 2008 to address surface water flooding.

How to Get Certainty: Lawful Development Certificates

If you're relying on PD rights for a project, you should strongly consider applying for a Lawful Development Certificate (LDC). This is a formal statement from the council confirming that your proposed development is lawful and doesn't require planning permission.

An LDC application for a proposed development costs £129 (England) — half the cost of a planning application. It takes 8 weeks. The certificate has no expiry date and provides legal protection if you ever sell the house or if the council later tries to claim you needed permission.

For work that has already been completed without planning permission (and where PD rights were arguably applicable), a certificate of lawfulness for existing development can be applied for. This is particularly useful if you're buying a house where previous work was done without consent.

Practical Advice

• Use the Planning Portal's interactive house guide (planningportal.co.uk) to get a preliminary sense of whether your project might fall under PD rights.
• Call your local planning authority's duty planner for informal pre-application advice — most councils offer this free for simple queries.
• If you're selling or remortgaging, lenders often require either planning permission or an LDC for any significant work done in the last four years.
• Hire a planning consultant or architect if your project is near the boundary of what's permitted — a few hundred pounds of professional advice can save you from enforcement action and costly demolition.

Planning law in England and Wales is genuinely complex and changes regularly. The guidance above is correct as of early 2026, but always verify with your local planning authority or a professional before starting work.