Planning Permission vs Permitted Development: What London Homeowners Need to Know

Do I need planning permission for this? Usually you mean a specific job. The kitchen you want to open onto the garden. The unused loft. The side passage used for bins. A garden room at the back.

Those jobs don't all need the same consent. This page is the fork: permitted development, prior approval, or a householder planning application. This isn't legal advice. The Planning Portal and GOV.UK are the official sources.

Kitchen layout sits in the kitchen extension guide. Going up versus building out sits in loft versus extension. The enforcement clock for work already done sits in the 10 year rule for loft conversions. That article isn't rewritten here.

Which Job, Which Consent

Start with the room, then the consent.

The kitchen you want to open. A modest rear on a house is the scheme most likely to stay within permitted development. A deeper rear — past 3 metres on a terrace or semi, or past 4 metres on a detached house — can still be permitted development if it stays within 6 metres or 8 metres and you get prior approval. A wraparound, a wide side, or a taller build more often needs a planning application. Rear versus wraparound is the footprint fork. The side return guide is the bins-alley job.

The unused loft. A rear dormer on a house can be permitted development if the volume, position and design stay inside Class B. Conservation areas, listed buildings and anything past those limits more often need an application. Loft conversion types is the design piece, not this page.

The garden room. Many garden rooms on houses are treated as outbuildings. The limits — and why living in one is not permitted development — are in garden room planning permission. Don't treat this guide as a second outbuilding checklist.

Knocking through. You shouldn't need planning permission to remove an internal wall in a house. Listed buildings are the exception. Building control and the party wall process can still apply. That's removing a load-bearing wall.

Planning Permission and Permitted Development

Planning permission is a formal application to your council. The council looks at the effect on neighbours and the street. Householder applications are the usual route for work on a single house — not a flat.

Permitted development is a general permission from government, not from your borough. If the job stays inside the limits, you don't submit a planning application. It's still a set of rules. It isn't a free pass.

The Planning Portal is clear: these householder rights apply to houses, not to flats or maisonettes. If you live in a flat, assume you need planning permission for external changes. If the house is leasehold, check the lease as well. That's a separate question from planning.

Building regulations are another regime again. They apply to most of this work whether or not you need a planning application.

Permitted Development Limits That Usually Decide It

These are the national householder limits on the Planning Portal extensions page and the loft conversion page. They are measured against the original house — the house as first built, or as it stood on 1 July 1948 if it is older. A previous owner's extension still counts.

Single-storey rear

• Detached: no more than 4 metres beyond the rear wall of the original house
• Semi-detached or terraced: no more than 3 metres
• Height: no more than 4 metres
• Eaves: no higher than the existing eaves
• Larger rears — up to 8 metres detached, or 6 metres on any other house — can still be permitted development if you are not on designated land or a Site of Special Scientific Interest, and you get prior approval

Side extension

• Single storey only
• No more than 4 metres high
• No more than half the width of the original house
• On designated land, including conservation areas, all side extensions need a householder application

Loft enlargement (Class B)

• Volume added, including any previous roof enlargement: 40 cubic metres on a terrace, 50 cubic metres otherwise
• Must not be higher than the existing roof
• Must not extend beyond the existing roof slope on the principal elevation where it fronts a highway — that's why a rear dormer is the usual permitted-development route
• Set back from the eaves; materials similar in appearance to the house
• The house must not be a flat, and must not be on Article 2(3) designated land — that includes conservation areas

The interactive house is a rough check, not a certificate. For the full wording, use the Portal pages and the GOV.UK technical guidance.

When You Need a Planning Application

Expect a householder application, rather than relying on permitted development, when any of these apply.

The property has restrictions

• Conservation area, or other designated land. Side extensions need planning. Class B loft enlargements are not permitted development. Cladding and some other external work are restricted.
• Listed building. You need listed building consent for significant works, inside or out. That's a separate consent from planning.
• Article 4 direction. The council has removed some or all permitted development rights. Common in conservation areas. Check with the borough.
• Already extended. Previous extensions, roof alterations and outbuildings count toward what is left.
• Flat or maisonette. These householder rights do not apply.

The design is past the limits

• The rear or side is larger or taller than the figures above
• The loft volume or position is past Class B
• Materials would not be of a similar appearance to the existing house
• You are building forward of the principal elevation, or a side elevation that fronts a highway

A neighbour having "done the same thing" doesn't decide your house. Their rights may already have been used. They may have planning permission. They may have built without it.

Prior Approval for a Larger Rear

Prior approval is only for a larger single-storey rear. It's still permitted development, with an extra step.

• Terrace or semi: more than 3 metres and up to 6 metres
• Detached: more than 4 metres and up to 8 metres

You apply before you start. The council consults adjoining neighbours. If a neighbour objects, the council decides whether the effect on amenity is acceptable. The official guidance note gives adjoining neighbours a minimum of 21 days to comment, and the council 42 days to determine the application. If they don't notify you within those 42 days, the development may go ahead — provided everything else about permitted development still holds.

It can't be used after you've built. Work that's already up is a different problem.

Check the current fee on the fee calculator. Don't rely on an old figure from a blog.

If You Need a Householder Application

Submit through the Planning Portal or your council. You need enough drawings to describe the proposal — typically a site plan, a location plan, and plans of what you're building.

A householder decision should be made within 8 weeks from validation. That is the Planning Portal householder page. Larger or more complex applications can take 13 weeks. The council should agree any extra time with you in writing. Some London boroughs are slower.

The council publicises the application and consults neighbours. Anyone can comment. A comment isn't an automatic refusal.

Fees are set nationally and they change. As of April 2026 the Portal's householder page lists current bands and points you to the fee calculator. Use that, not a remembered amount.

Many councils offer paid pre-application advice. It isn't binding. It's useful when the house is restricted or the scheme is tight.

Once permission is granted, you normally have 3 years to begin the work. That's GOV.UK and the Town and Country Planning Act. You don't have to finish inside those 3 years. If you haven't started, you apply again. The decision notice can set a different period.

Check Before You Dig

1. Planning history. A previous owner may already have used the allowance. Check the borough's planning search before you assume the rights are intact.
2. Lawful Development Certificate (proposed). Written proof, before you build, that the job is permitted development. Target 8 weeks. Fee via the calculator.
3. Planning Portal. The extensions, loft and outbuildings pages, plus the interactive house.
4. The designer or builder. Part of a proper consultation is checking which route you are actually on.

If the work is already there and you're being asked about enforcement time limits, that's the 10 year rule, not a new set of size limits.

If you want the planning position handled as part of design and build, book a consultation. We look at the kitchen, the loft, the side passage and the garden, and tell you which consent the job needs before you freeze the drawings.

Common Myths

"My neighbour did it, so I can too." Not necessarily. Different rights, a permission you cannot see from the street, or work that was never approved.

"If you cannot see it, you do not need permission." Visibility isn't the test. Size, height, location and the status of the house are.

"Permitted development means no rules." It's a detailed set of limits. Building regulations still apply.

"Internal work never needs consent." In a house, internal alterations including removing a wall usually do not need planning. In a listed building, significant works do. See the Planning Portal internal walls page.

Further Reading

Internal:

• Kitchen extension guide
• Loft vs extension
• Rear vs wraparound
• Side return guide
• Garden room planning
• 10 year rule
• Removing a load-bearing wall
• Extension costs

Official:

• Planning Portal extensions
• Planning Portal loft conversions
• Lawful Development Certificate
• Fee calculator
• GOV.UK when you need planning permission