When do I need planning permission?

You generally need planning permission for: building a new house, converting a property to a different use (e.g. house to flats), large extensions that exceed permitted development limits, building in a conservation area, listed building alterations, building on green belt land, and commercial development. Many smaller projects fall under 'permitted development rights' and don't need planning permission — for example, a single-storey rear extension up to 4 metres (detached) or 3 metres (other houses). Always check with your local planning authority if in doubt.

How long does planning permission take?

The statutory determination period is 8 weeks for most applications and 13 weeks for major developments (10+ homes or 1,000+ sqm). In practice, many applications take longer — especially if additional information is requested or the application goes to committee. You can generally expect a decision within 8–12 weeks for a straightforward householder application, though complex cases can take 6 months or more. Pre-application advice, if offered by your council, can speed things up by identifying issues before you formally apply.

How much does planning permission cost?

The standard fee for a householder application in England is £258 (2025/26). Other fees include: new dwelling £578 per unit, change of use £578, and outline planning permission varies by site area. In Wales, Scotland, and Northern Ireland, the fees are different. On top of the application fee, you may need to pay for architectural drawings, planning consultants, ecological surveys, and other supporting documents — these can add £2,000–£10,000+ depending on complexity.

What happens if I build without planning permission?

If you carry out development without the required planning permission, the local authority can serve an enforcement notice requiring you to undo the work, alter it to make it acceptable, or demolish it entirely. You can apply for 'retrospective planning permission' to try to regularise the situation, but approval isn't guaranteed. If enforcement action is taken and you don't comply, it's a criminal offence. Unauthorised development can also cause problems when you try to sell the property — buyers' solicitors and mortgage lenders will check for planning compliance.

Planning Permission Guide UK — When You Need It & How to Apply | PocketWise

Planning permission controls what you can and can’t build, extend, or change about a property. Here’s when you need it, how to apply, and what it costs.

Do I Need Planning Permission?

Projects That Usually NEED Planning Permission

Project	Why
Building a new house	Always needs full planning permission
Extensions exceeding permitted development limits	See limits below
Loft conversions that alter the roof shape significantly	Dormers may need permission
Converting a house into flats	Change of use
Building a new driveway with non-porous surface	In front of the property
Commercial buildings	Most changes need permission
Work on a listed building	Needs Listed Building Consent as well
Work in a conservation area	Tighter restrictions apply
Demolition	Often needs prior approval
Changing the use of a building	E.g. shop to house, office to residential

Projects That Usually DON’T Need Permission (Permitted Development)

Project	Key limits
Single-storey rear extension	Up to 4m (detached) or 3m (others) — or 6m/8m under prior approval
Garden shed/outbuilding	Max 2.5m height if within 2m of boundary; no more than 50% of garden covered
Loft conversion (roof lights, no dormer)	Up to 40 m³ (terrace) or 50 m³ (detached/semi)
Patio/decking	Max 30cm above ground level
Fences and walls	Up to 2m height (1m next to a highway)
Satellite dish	1 dish, within size limits
Solar panels	On roof (not on listed buildings or conservation area front elevations)
Internal alterations	No planning permission needed (unless listed building)
Replacing windows	Like for like (not in conservation areas — may need permission)
Porch	Max 3 m², 3m high, 2m from highway

Important: Permitted development rights may be removed in conservation areas, Areas of Outstanding Natural Beauty, National Parks, and for flats/maisonettes. Always check.

Planning Permission Fees (England, 2025/26)

Application type	Fee
Householder application (extension, alteration)	£258
Outline planning permission (up to 2.5 hectares)	£578 per 0.1 hectare
Full permission — new dwelling(s)	£578 per dwelling (first 50), then £462 per dwelling
Change of use	£578
Listed Building Consent	£0 (free)
Lawful Development Certificate (confirming PD rights)	£129 (existing) or £258 (proposed)
Advertisement consent	£132
Prior approval (larger home extension)	£120

Fees in Other Nations

Nation	Typical householder fee
England	£258
Wales	£230
Scotland	£300
Northern Ireland	£245

Additional Costs

Item	Typical cost
Architectural drawings	£500–£3,000
Planning consultant	£500–£2,000+
Structural engineer report	£300–£800
Ecological survey (bats, newts, etc.)	£300–£1,500
Tree survey/arboricultural report	£300–£800
Flood risk assessment	£500–£2,000
Heritage/design statement	£500–£1,500
Transport assessment (larger projects)	£2,000–£10,000+

How to Apply for Planning Permission

Step	Action
1	Check if you need permission — contact your local planning authority or check the Planning Portal
2	Pre-application advice (optional but recommended) — meet the planning officer before applying
3	Prepare drawings and documents — hire an architect or use a planning consultant
4	Submit application via the Planning Portal (planningportal.co.uk) or directly to your council
5	Pay the fee
6	Validation — council checks your application is complete
7	Consultation — neighbours notified, site notice erected (21 days)
8	Decision — within 8 weeks (householder) or 13 weeks (major)
9	If approved — check any conditions before starting work
10	If refused — appeal to the Planning Inspectorate or amend and resubmit

Timeline

Stage	Typical duration
Pre-application advice	2–4 weeks
Preparing drawings/documents	2–6 weeks
Validation by council	1–2 weeks
Consultation period	21 days
Decision (householder)	8 weeks from validation
Decision (major development)	13 weeks from validation
Total (straightforward)	12–16 weeks from start to decision

What Happens After Approval

Requirement	Detail
Conditions	Most approvals come with conditions (e.g. materials must match existing, landscaping must be completed, hours of work) — you must comply
Time limit	Usually 3 years to start work — if you don’t begin within this period, permission expires
Building Regulations	Planning permission and Building Regulations are separate — you likely need both
Party Wall Agreement	May be needed if work affects a shared wall or boundary

If Your Application Is Refused

Option	Detail
Ask for the reasons	The decision notice will state why — common reasons: impact on neighbours, scale, design, impact on character of area
Amend and resubmit	Address the reasons for refusal and submit a new application (you can apply again for free within 12 months)
Appeal	Appeal to the Planning Inspectorate — free, but can take 6–12+ months
Hire a planning consultant	Can help strengthen your case for resubmission or appeal

Retrospective Planning Permission

Detail	Information
What it is	Applying for permission after you’ve already built something
Is it legal?	Yes — it’s a valid application type
Is it guaranteed to be approved?	No — assessed on the same criteria as a normal application
If refused	You may be required to undo the work via an enforcement notice
Time limit for enforcement	Generally 4 years for building work, 10 years for change of use
After 4/10 years	If no enforcement action is taken, the development may become lawful (apply for a Lawful Development Certificate)