Common projects: permitted development or planning permission needed?
This table covers typical scenarios for a standard house in England outside a conservation area or Article 4 direction zone. Rules differ in Scotland, Wales and Northern Ireland. Always verify with your local planning authority (LPA) before starting work.
| Project | Permitted development? | Notes |
|---|---|---|
| Single-storey rear extension | Usually yes (within limits) | Max 3 m depth for attached, 4 m for detached; no more than 4 m high. Up to 6 m / 8 m under the neighbour-consultation scheme. |
| Two-storey rear extension | Sometimes (within limits) | Max 3 m from rear wall; must not be within 7 m of the rear boundary. |
| Side extension | Sometimes | Max half the width of the original house. Two-storey side extensions almost always need permission. |
| Loft conversion (no roof extension) | Usually yes | Max 40 m3 (terraced) or 50 m3 (semi/detached). No extension beyond the existing roof slope facing a highway. |
| Dormer loft conversion | Usually yes (rear-facing) | Rear dormers within size limits are usually PD. Front-facing dormers visible from a highway typically need permission. |
| Conservatory or orangery | Usually yes (within limits) | Same limits as single-storey rear extension. Must not cover more than half the garden. |
| Garage conversion | Usually yes | Internal conversion with no external changes is generally PD. External alterations may need permission. |
| Garden room or outbuilding | Usually yes (within limits) | Max 2.5 m height if within 2 m of boundary. Must not cover more than 50% of the garden. |
| Front extension or porch | Usually not | Any extension to the front elevation facing a highway typically needs permission. |
| New driveway (permeable surface) | Usually yes | Permeable surfacing (gravel, block paving with soakaways) is generally PD. Solid impermeable surfaces over 5 m2 need permission. |
| Listed building works (any) | No (LBC required) | Listed Building Consent is required for almost any works affecting character. Separate from planning permission. |
| Works in conservation area | Restricted | PD rights are often removed by Article 4 directions. Check with your LPA before any external alterations. |
| Change of use (e.g. house to flats) | No | Splitting a house into flats or changing use class requires a full planning application. |
| Works to a flat or maisonette | No | Flats have no permitted development rights for extensions or loft conversions. Full planning is always needed. |
PD = permitted development. Rules as at 2026 for England only. Scotland, Wales and Northern Ireland have separate regimes. This table is a guide only; confirm with your local planning authority.
Permitted development rights explained
Permitted development rights are a set of automatic planning permissions granted by Parliament rather than your local council. They allow certain types of works to proceed without a formal planning application, provided they stay within specified limits on size, height, materials and position.
PD rights apply to the property as it was originally built, not as it stands today. If a previous owner already used up some of the PD allowance with an extension, the remaining PD budget is reduced. That is why a Certificate of Lawful Development (CLD), which costs around £129 in England, is often worth obtaining even for PD projects: it is a formal record from the council that your works are lawful.
Some areas have Article 4 directions, which remove some or all PD rights. These are common in conservation areas, National Parks and Areas of Outstanding Natural Beauty. Your council's planning portal or a quick phone call can tell you whether an Article 4 applies to your address.
When you definitely need full planning permission
Always apply for full planning permission if any of these apply:
- The project exceeds the permitted development size limits (even by a small amount).
- The property is a listed building (Listed Building Consent is also required).
- The property is a flat or maisonette.
- The site is in a conservation area and you are altering the roof, adding a dormer, cladding the exterior or extending at the side.
- Your area has an Article 4 direction removing relevant PD rights.
- You are changing the use of the building, for example from a single dwelling to flats, or from residential to commercial.
- The project involves demolishing a building of 115 m2 or more.
- Works would affect a public right of way.
Planning permission vs building regulations: what is the difference?
Planning permission and building regulations are two completely separate legal systems, and you often need both. Planning permission controls whether you can build, where, and how it looks from outside. Building regulations control how the building is constructed to ensure it is structurally safe, fire-resistant, thermally efficient and meets minimum standards.
Many projects that are permitted development still require building regulations approval, including loft conversions, garage conversions, most extensions, and any structural work such as removing a load-bearing wall. Conversely, some projects that need planning permission may have simpler building regulations requirements.
Building regulations are enforced by your local authority building control (LABC) or an approved inspector. Fees vary by project but typically range from £200 for a small conservatory to £2,000+ for a larger extension. Work carried out without sign-off can create problems when you come to sell.
Use the Planning Portal and budget with our planner
The Planning Portal (planningportal.co.uk) has a free interactive house guide to check whether your project needs permission. Our planner helps you set a realistic buying and refurbishment budget before you commit, including planning fees, architect and building regs costs as separate line items.
Retrospective planning: the risks
If you build without planning permission where it was required, the council can issue an enforcement notice requiring you to undo the works at your expense. More practically, it will appear on a local search when you sell, and buyers, surveyors and mortgage lenders will want it resolved. Retrospective planning applications (for lawful development) are possible but not guaranteed to succeed. Do not assume the council will not notice.