Most single storey rear extensions in Croydon can be built without a full planning application, thanks to permitted development rights. The catch is that those rights have hard limits on size, height and location, and plenty of homes in the borough sit in conservation areas or have had their rights removed. This guide sets out what you can build, when you must apply, and how to check before you spend money on drawings.
Permitted development is a national set of rules that lets homeowners extend without a planning application, provided the work stays within set limits. For a detached house, a single storey rear extension can project up to 4 metres from the original rear wall. For a semi detached or terraced house, which covers most of Croydon's Victorian and 1930s stock, the limit is 3 metres.
Under the larger home extension scheme, those figures rise to 8 metres for detached and 6 metres for semis and terraces, but only after you complete a prior approval application. The council notifies your neighbours and, if nobody objects within 21 days, you can proceed. The extension must also stay under 4 metres in height, or 3 metres at the eaves if it sits within 2 metres of a boundary.
Croydon has more than 20 conservation areas, including Bradmore Green in Old Coulsdon, Norwood Grove, Chatsworth Road, and the Webb Estate in Purley. If your house is in one, side extensions and rear extensions over one storey need full permission, and cladding or altering the front elevation is restricted. Listed buildings need listed building consent for almost any change.
Many newer estates and converted houses had permitted development rights removed as a condition of the original approval. This is common on developments built since the 1990s and on almost every flat. If you own a flat or maisonette, you have no permitted development rights for extensions at all. The only reliable way to know is to check your title deeds and the original planning decision on Croydon Council's online planning register.
The safest route, whether or not you think you qualify, is a Lawful Development Certificate. This is a formal confirmation from Croydon Council that your extension is permitted development, and it costs around half the fee of a full application. Mortgage lenders and buyers often ask for it when you sell, so it pays for itself. Expect a decision in about 8 weeks.
If you do need full householder planning permission, the application fee is set nationally and currently sits a little under 300 pounds. On top of that you will need scaled drawings, usually 600 to 1,500 pounds from an architectural technician for a straightforward extension. The council's target is 8 weeks for a decision, though it can stretch longer when officers are busy or neighbours object.
Even when no planning application is needed, every extension still needs building regulations approval. This covers structural work, foundations, insulation, drainage, fire safety and electrics. You can use Croydon's building control team or an approved private inspector, and the fees typically fall between 500 and 1,200 pounds depending on the floor area.
Your builder should be handling this as part of the job, with inspections at foundation, damp course, drainage and completion stages. You should also budget for a party wall agreement if you are building on or near a shared boundary with a neighbour, which is standard for the terraced streets around Thornton Heath, Addiscombe and South Norwood. A surveyor's fees for this usually run from 700 to 1,500 pounds per neighbour.
Only through the prior approval route under the larger home extension scheme. You notify the council, they consult neighbours for 21 days, and if there are no valid objections you can build up to 6 metres on a terrace or semi.
The council can serve an enforcement notice requiring you to alter or demolish the work, and it will cause problems when you sell. You can apply for retrospective permission, but there is no guarantee it will be granted.
Most loft conversions and garage conversions are permitted development on houses outside conservation areas, provided volume limits are respected. Both still require building regulations approval regardless.