Croydon lofts split by street. The Victorian and Edwardian terraces of Addiscombe, South Norwood, Thornton Heath and Selhurst have deep roof slopes that suit a rear dormer. The 1930s semis of Purley, Shirley, Coulsdon, Sanderstead and Selsdon are hipped, so the choice is between a rear dormer and a hip-to-gable end. The large detached houses of the Webb Estate, Kenley and Woodcote are the cases where conservation or Green Belt status can change the route. A loft project here starts by finding out which of those three you are in.
The permitted development rules for loft conversions
A loft conversion with a rear dormer is permitted development on a house if the added roof volume is no more than 40 m³ on a terraced house or 50 m³ on a semi-detached or detached house, the dormer sits at least 200 mm back from the eaves and no higher than the ridge, there is no dormer on the roof slope facing the road, materials are similar in appearance, and side windows are obscure-glazed.
Flats and maisonettes have no permitted development rights, so a loft to a top-floor flat always needs planning permission. Full-width box dormers that reach the ridge, and hip-to-gable conversions on semis whose volume exceeds 50 m³, also fall outside the allowance.
What changes in Croydon
Roof extensions are not permitted development in a conservation area, so a dormer or hip-to-gable there needs a householder planning application designed to the area's appraisal.
The local constraints that most often decide the route in Croydon are listed below, taken from our Croydon area page. Each one is a reason to confirm the address on Croydon's constraints map before relying on permitted development.
- Conservation areas and Local Areas of Special Character. Croydon has numerous conservation areas, including the Webb Estate, Chatsworth Road, Church Street, Norwood Grove and Bradmore Green, plus Local Areas of Special Character identified in the Local Plan. Source
- Green Belt and Metropolitan Open Land. The southern third of the borough, including Coulsdon, Kenley, Sanderstead, Selsdon and Addington, contains extensive Green Belt and Metropolitan Open Land. Source
- Article 4 directions. Croydon has Article 4 directions in several conservation areas, including the Webb Estate, removing permitted development for front alterations, boundary treatments and some roof works. Source
- Flood risk: Wandle and surface water. The River Wandle rises in Croydon and parts of Waddon, Beddington borders and the town centre carry fluvial or surface-water flood risk. Source
How Croydon judges a dormer now that its design guide has gone
Croydon's Suburban Design Guide (SPD2), which included detailed roof extension guidance, was revoked by the council on 25 July 2022 and stopped being used to decide planning applications from the next day. The council's own planning pages say the Local Plan and wider development plan policies are unchanged, and that replacement guidance on residential extensions and alterations is to be developed. We therefore treat any older rule of thumb about dormer width as a design starting point, not a test the council applies.
The test that remains is in the Croydon Local Plan (2018). Policy DM10.1 asks proposals to respect the development pattern, scale and appearance of the surrounding area, and DM10.7 asks that the design of a roof form positively contributes to the character of the local and wider area by being sympathetic with its local context. In practice a dormer is judged against its own street: the roofs of the neighbouring terrace or the hips of the neighbouring semis.
Where roof work is more restricted in conservation areas and the Green Belt
Croydon has 21 conservation areas, and the council states that planning permission is required for extensions and alterations to the roof in them. Article 4 directions apply in three: Chatsworth Road, The Waldrons and Kenley Aerodrome. In Chatsworth Road the direction, in force since 21 January 2016, requires planning permission for all alterations to the roof of a dwelling house. Always check a property against the council's conservation area and Article 4 pages before assuming a loft route.
On houses in the Metropolitan Green Belt or Metropolitan Open Land, Policy DM26.2 says extensions should not be more than 20% of the original floor space or volume, or 100 square metres, whichever is smaller. Policy DM26.3 adds that the council looks at all previous extensions since 1948 and at the use of roof spaces as living areas when deciding whether an extension is disproportionate, so a loft can count on a house in Sanderstead, Selsdon or Coulsdon that has already been extended.
What Croydon planning officers look for
Refusals most often cite two-storey side extensions without a set-back that create a terracing effect, rear extensions that breach the 45-degree line, oversized rear dormers that wrap the hip, and any loss of gaps between houses in Local Areas of Special Character. Hip-to-gable lofts on ordinary semis are generally accepted. Pre-application advice is available for a fee, and decision times often exceed the statutory 8 weeks; allow 10–14 weeks.
Fees and timelines
Croydon decides a householder application or a Lawful Development Certificate within 8 weeks of validation. The council fee is £528 for a householder application and £264 for a Lawful Development Certificate (England, from 1 April 2025; verify before applying).
Our own fee is fixed once quoted. The quote tool gives an indicative figure in minutes and a written quote follows within 24 hours.
Primary sources
- Croydon Council: Supplementary planning documents and guidance (SPD2 revocation)
- Croydon Council: Croydon Local Plan 2018 (policies DM10 and DM26)
- Croydon Council: Conservation areas
- Croydon Council: Chatsworth Road Conservation Area Article 4 direction
- The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2: the permitted development limits quoted above.
- Planning Portal: do you need permission: the national guidance and the application service every council accepts.
- London Borough of Croydon: planning: the council's own constraints map, validation checklist and pre-application service.
