Planning guide

When do I need planning permission?

A plain-English guide to which common home projects need planning permission and which are permitted development, and how we confirm the right route for your project before any drawings begin.

Get an instant quote Ask us about your project

Not every project needs a planning application. Many smaller changes fall under permitted development: a set of works the government allows without a formal application, within limits on size, height and position. Larger projects, and almost anything on designated land or a listed building, need planning permission: a formal application to your local council.

The pages below explain where each common project usually sits. They are a guide to the rules in England, not a definitive legal position: the exceptions matter, which is why checking the route for your specific property is one of the very first things we do, on the house, before you commit to anything.

Common projects

Choose your project

Pick the project closest to yours to see whether it typically needs permission, the key limits, and how we can help.

Extending your home

ExtensionsSingle and double-storey, side and rear: the depth, height and coverage rules that decide it.Loft conversionsDormers, hip-to-gable and rooflights, the 40/50m³ volume rule and when it applies.Garage conversionsTurning an integral or attached garage into a room: usually internal, usually permission-free.Additional storeysExtending upwards to add a floor, the newer prior-approval route and its 18m height cap.BasementsConverting a cellar versus digging a new basement, two very different planning positions.ConservatoriesTreated like any extension for planning, but often exempt from building regs.PorchesSmall enough and far enough from the highway? Usually permitted development.

Garden & outdoors

Outbuildings & garden roomsGarden offices, studios and sheds: the coverage, height and 'incidental use' rules.DeckingLow and modest is fine; height and garden coverage are the triggers.Patios & drivewaysRear patios are usually free; front gardens hinge on permeable surfaces.Fences, gates & garden walls1m next to a highway, 2m elsewhere, the heights that need permission.Dropped kerbsA vehicle crossover is a highways matter, and sometimes planning too.

Alterations & repairs

Internal wallsRarely a planning matter, but load-bearing walls are firmly a building-regs one.Doors & windowsLike-for-like is usually fine; bay windows, conservation areas and listing are not.Roof worksRe-roofing and rooflights are usually fine; changing the roof shape is not.External wallsRepairs and painting are free; cladding and render depend on where you live.DemolitionOften needs prior approval; conservation areas and certain buildings need permission.

Change of use & new homes

Change of useBarn to home, shop to flat, office to house, use classes and prior approval.Self-build & new homesA new dwelling always needs permission, and the design is where it is won.Working from homeUsing a room for work is usually fine; a business that changes the character isn't.

Common questions

Planning permission, in brief

When do I need planning permission?

It depends on the project, the property and where it is. Many smaller works, some extensions, loft conversions, outbuildings and exterior changes, are permitted development and need no application, within set limits. Larger works, and anything on designated land or where rights have been removed, need a full planning application. We check which applies to your project before any drawings are produced.

What is the difference between planning permission and permitted development?

Permitted development is a set of works you can carry out without a formal planning application, within national limits. Planning permission is a formal application to your local council for works that fall outside those limits. Where a project is permitted development, a Certificate of Lawful Development can give you written proof.

Can CR Design check whether I need permission?

Yes, confirming the right route is one of the first things we do on every project. We assess your plans against permitted development and local rules, tell you whether you need a full application or a Certificate of Lawful Development, and prepare the drawings either way.

More answers on our FAQs page, or read about our planning permission drawings service.

Still not sure? We'll check it for you

Tell us about your project and we'll confirm whether you need planning permission, permitted development or a Certificate of Lawful Development, then prepare the drawings either way.

Get an instant quote 0191 645 6000