If you're planning work on your home, you'll usually fall into one of three buckets: no planning permission needed, covered by Permitted Development rights, or a full planning application required. The trap is in the middle bucket: Permitted Development feels like a free pass, but the limits are detailed, and the consequences of getting it wrong can follow a house for decades. This guide is the plain-English map: what counts as what, how to check, and where the catches are.
The short version: most internal work needs no planning permission, many common extensions and lofts are covered by Permitted Development, and bigger or out-of-area-norm projects need a full application. Building Regulations are a separate process; most projects require them, regardless of whether planning permission is needed.
The three buckets
Almost every home project lands in one of these:
- No planning permission needed
- Covered by Permitted Development (PD); a national right, with conditions
- Full planning application required
If you understand these three, you've got 90% of the picture.
Bucket 1: No planning permission needed
Most interior changes don't need planning permission.
That includes:
- Internal layout changes (knocking through, new partition walls)
- Replacing kitchens and bathrooms
- Decoration, rewiring, replumbing
- Like-for-like replacement windows (outside conservation areas)
- Repairs and maintenance
You may still need Building Regulations approval for structural, electrical, plumbing or fire-safety work, but that's a different process. We come back to it further down.
Bucket 2: Permitted Development (PD)
Permitted Development is a national set of rights that lets you do certain work without applying for planning permission, provided you stay within published limits.
Common projects that often fall under PD:
- Single-storey rear extensions, within size and height limits
- Loft conversions, within volume limits (typically 40m³ for terraced houses, 50m³ for semis and detached)
- Garage conversions (where the garage stays attached and isn't extended)
- Garden outbuildings, below set height and coverage limits
- Replacement windows and doors (with conservation area exceptions)
- Solar panels, below a height limit and not on the front of a flat
The limits are specific. A few examples:
- A single-storey rear extension on a detached house can usually go up to 4m from the original rear wall (8m under the larger home extension scheme, which requires neighbour consultation), and 4m high.
- On a terraced or semi-detached house, those numbers are typically 3m and 6m.
- A loft dormer facing the road usually needs full planning permission, not PD.
A few important catches:
- PD doesn't apply to flats, only to houses
- Listed buildings lose almost all PD rights
- Conservation areas have tighter rules; some PD is removed
- Article 4 directions are local council orders that remove PD rights for a specific area or type of work, common in popular conservation areas and high-demand neighbourhoods
- You may still need other consents: Building Regulations, party wall, and listed building consent
The most useful piece of paper if you're using PD is a Lawful Development Certificate (LDC). It's an optional application that gets the council to formally confirm the work is lawful. It costs less than full planning permission and gives you proof when you come to sell.
Bucket 3: Full planning application
You need a full planning application when:
- The work exceeds PD limits
- The property is a flat
- The property is listed (you'll also need listed building consent)
- You're in a conservation area, or Article 4 area, and the work isn't allowed under the tighter rules
- You're changing the use of the building (e.g. house to HMO, or residential to short-let in some areas)
- You're building something new rather than altering
Full applications take time. The target determination period for householder applications in England is eight weeks. Anything contested takes longer. There are fees; confirm the current amount with your council, as they're updated periodically and differ across England, Wales, Scotland and Northern Ireland. Neighbours are formally consulted.
If your application is refused, you can appeal to the Planning Inspectorate. Appeals are slow, six to nine months is common, and the burden is on you to show the council was wrong.
Why this matters, what happens if you get it wrong
If you do work that needed permission and didn't get it, three things can happen:
- Your council can issue an enforcement notice demanding that the work be undone or applied for retrospectively
- You may need a retrospective application, which costs the same as a normal one and may be refused
- A future buyer's solicitor will spot the lack of consent during conveyancing. Most lenders won't proceed without it being resolved.
In England, the enforcement window for unauthorised building work was extended to 10 years for breaches occurring after April 2024 (it was previously four years). The detail differs in Wales, Scotland and Northern Ireland. Confirm with your local planning authority.
Practical impact: planning issues are one of the most common reasons sales stall at conveyancing. Indemnity insurance can sometimes cover the risk, but it's a workaround, not a fix.
How to check before you start
A clear order of operations:
- Identify which bucket your project sits in. The Planning Portal's interactive house tool is a sensible starting point.
- Check your local restrictions. Is the property listed? In a conservation area? Subject to an Article 4 direction? Your council's planning map will tell you.
- Check what's already been approved on the property. Past applications set a useful precedent. Councils often follow their own previous decisions on the same street. You can check this on Property Looker, which holds 16 million UK planning records.
- Talk to the council's duty planner. Most councils offer free or low-cost pre-application advice for householders. It's worth using.
- If you're using PD, consider a Lawful Development Certificate. Cheap insurance against future disputes.
- Submit your application via your council's portal or via the national Planning Portal.
For anything complex: listed, large, in a conservation area, or a change of use, get a planning consultant or architect involved before you spend money on drawings.
Planning permission vs Building Regulations
This is the most common point of confusion, so worth a short note.
- Planning permission is about whether you're allowed to do the work at all: does it fit the local plan, does it affect neighbours, is it acceptable as a use of the land?
- Building Regulations are about how the work is done: structural safety, insulation, fire, ventilation, drainage, and energy efficiency.
Most building work needs Building Regulations approval, whether or not it needs planning permission. A garage conversion, for example, usually doesn't need planning permission but absolutely needs Building Regs. The short rule: assume Building Regs apply and check planning separately. (We've covered this in more detail in Planning permission vs Building Regulations: what's the difference?)
UK nation notes
The high-level system is similar across the UK, but the detail varies:
- England; Town and Country Planning Act 1990, plus the General Permitted Development Order
- Wales; broadly similar framework with separate Welsh PD rules
- Scotland; similar in shape but with distinct PD rights and a separate process via ePlanning Scotland
- Northern Ireland; handled by the NI Planning Service
If your project is close to the edge of PD limits, the details of your nation's rules matter. Don't assume English guidance applies in Wales, Scotland, or Northern Ireland.
The bottom line
Most home projects either need no planning permission or fall under Permitted Development. The complication is in the limits; a few centimetres or one extra dormer can be the difference between PD and a full application. Getting it wrong rarely makes work impossible, but it can cost time, money, and a future sale.
The cheap insurance is to check before you start. Half an hour with the council's duty planner, a look at the property's planning history, and a Lawful Development Certificate at the end can save you from a problem that resurfaces a decade later when you try to sell.
Before you instruct an architect or buy materials, do you know which of the three buckets your project sits in?
Find planning permissions on Property Looker
Researching a property or planning home improvements? Property Looker holds 16 million UK planning records. Search any address on ukpropertylooker.com to see what's already been approved, refused, or built on the site before you commit. Find your property here: https://ukpropertylooker.com/
Disclaimer: This article is for general information only and does not constitute planning or legal advice. Planning rules vary by location and are updated periodically. Always confirm the current position with your local planning authority.