Most single storey rear extensions in Brighton and Hove can be built without a full planning application, but the exceptions catch people out more often here than in most towns. Between the conservation areas, the sheer number of converted flats and the South Downs National Park sitting on the city's northern edge, the honest answer is usually "probably not, but check first". Here is how to work out which side of the line your project falls on before you spend money on drawings.
Permitted development rights let you extend a house without applying for planning permission, provided you stay inside a fairly rigid set of rules. For a single storey rear extension, the headline figures are the ones to check against your own garden.
Every one of these is a hard limit rather than a guideline. Go over by even a small margin and the whole extension becomes unauthorised, which is a problem that tends to surface years later during a sale.
Brighton and Hove has more than thirty conservation areas, covering large parts of Kemp Town, Montpelier and Clifton Hill, Round Hill, Queen's Park, Willett Estate and much of central Hove. Inside one, side extensions lose permitted development rights entirely and cladding is restricted, though a modest rear extension can still be permitted development. If your home is listed, and the Regency squares and terraces contain a great many, you will also need listed building consent regardless of size.
The single biggest catch is flats. Permitted development rights apply to houses only, so if you live in a converted flat or maisonette, which is an enormous share of Brighton's housing stock, any extension needs a planning application. The same applies if your property has already been extended since 1948, because the rules measure from the original house as built, not from where the back wall stands today.
Parts of Patcham, Stanmer, Ovingdean and Rottingdean fall within or adjoin the South Downs National Park, where the National Park Authority is the planning authority and permitted development allowances are tighter. Some properties also carry conditions from their original consent that removed permitted development rights, common on newer estates, which is worth checking in your deeds.
If you want a rear extension deeper than the standard limit, the larger home extension procedure allows up to 6m on a terraced or semi-detached house and 8m on a detached one, still single storey, still within the height limits. You notify Brighton and Hove City Council, they write to your immediate neighbours, and if nobody objects within 21 days it proceeds without a full application.
This suits a lot of Brighton's long, narrow rear gardens on streets like those off Elm Grove or Preston Drove. The fee is modest, typically around £120, and the decision period is eight weeks. The risk is real though: one neighbour objection sends it to a full officer assessment on overshadowing and overlooking, which on tightly packed terraces can go either way.
Even when your extension clearly is permitted development, apply for a Lawful Development Certificate. It costs roughly half a householder application fee, around £130 at the time of writing, and gives you a formal council document confirming the works were lawful. Conveyancing solicitors ask for it routinely, and without one a buyer's surveyor can stall a sale for weeks.
Planning permission and Building Regulations are separate consents, and skipping the second is the more expensive mistake. Every extension needs building control approval for foundations, insulation, structural openings and drainage. Brighton's chalk subsoil and older properties frequently mean deeper foundations than expected, and if you are building near a shared boundary on a terrace you will also need a Party Wall Award agreed with your neighbours before work starts.
A householder application has a statutory eight week determination period, though it is sensible to allow ten to twelve weeks from submission in practice. Conservation area or listed building cases often sit at the longer end.
Usually yes, but the eaves height is capped at 3m within 2m of a boundary, and you will need a Party Wall Agreement before starting. Building off the boundary by even 100mm can simplify both the structure and the conversation with your neighbour.
You can apply for retrospective planning permission or, if the work has stood unchallenged long enough, a Lawful Development Certificate based on the passage of time. Get planning advice before a sale rather than during one, because it is far cheaper to resolve without a deadline.
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