Planning guide
Permitted development for extensions and lofts
Permitted development is a standing national permission. If your project stays inside the limits and none of the exclusions apply, you can build without a planning application. The rules are detailed rather than complicated, and they reward reading properly.
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The principle in one paragraph
Government sets out classes of development that are permitted without an application, subject to conditions on size, position, height, materials and location. Your council does not grant it and cannot refuse it, but it can confirm whether your scheme qualifies, and it can have removed the rights for your particular house or area. The limits change from time to time, so the Planning Portal and your local planning authority are the authoritative sources, not a builder's memory.
The conditions that matter most in practice
These are the ones that decide most real projects.
- Rear depth limits, which differ between detached houses and semis or terraces
- The larger home extension route, where deeper single storey rear extensions can go ahead after prior approval and a neighbour consultation
- Height limits at the eaves and overall, particularly within two metres of a boundary
- How much of the garden can be covered in total by all buildings
- Materials being similar in appearance to the existing house
- Side extensions being limited to single storey and to half the width of the original house
- Roof volume allowances for loft conversions, with lower limits on terraces than detached homes
- No verandas, balconies or raised platforms, and side facing upper windows needing obscure glazing
How prior approval works
Prior approval is not full planning permission and it is not a formality either. You notify the council with drawings, they notify the adjoining neighbours, and if nobody objects within the consultation period the work can proceed. If a neighbour does object, the council considers the impact on their amenity, mainly light and outlook, and decides.
It is a genuinely useful route for a deeper rear extension, and it is quicker than a full application. The practical advice is simple. Speak to your neighbours before the letters arrive, not after.
Where permitted development rights do not exist at all
- Flats, maisonettes and most converted buildings
- Listed buildings, where consent is required regardless of size
- Houses where a planning condition removed the rights, common on newer estates
- Areas covered by an Article 4 direction
- Some rights are reduced within conservation areas and protected landscapes, including much of the High Weald
Check first, build once
We establish the planning route at the free site visit, before drawings and before a fixed price written quote is issued. Forty plus years of Kent projects means we have taken most routes more than once.
FAQs
Common questions
Is permitted development the same everywhere in England?
The national rules are, but local designations change what applies to your house. Conservation areas, protected landscapes and Article 4 directions all restrict it.
Does permitted development mean no paperwork at all?
No. Building regulations still apply, and a lawful development certificate is strongly recommended as proof for future sale.
How long does prior approval take?
It is a defined consultation and determination period rather than an open ended one. Your council will confirm the current timescale when you submit.
Can a neighbour block a permitted development extension?
Not by objecting in principle. Under prior approval the council weighs the impact on their amenity, so a reasonable, well designed scheme normally proceeds.
Do loft conversions have their own allowance?
Yes, based on added roof volume, with a lower allowance for terraced houses. Dormers must not go forward of the roof plane facing the highway.
What if my house was already extended by a previous owner?
That earlier work counts against the allowance. Rights attach to the original house as built, not to each new owner.
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