Wraparound extensions in Hounslow depend on the house. Typical homes here: Edwardian and Arts and Crafts houses in Bedford Park and Chiswick; Victorian terraces in Brentford, Old Isleworth and around Chiswick High Road. Designations to check first: Conservation areas; Article 4 directions; Thames flood zones. Applications are decided by London Borough of Hounslow and the Hounslow Local Plan 2015–2030.
The permitted development rules for wraparound extensions
A wraparound combines a side-return infill with a rear extension. Permitted development assesses each part separately, so the side element must stay within half the width of the original house and the rear element within 3 m or 4 m, and the two together must not exceed 50 per cent of the land around the original house.
Because the combined footprint is treated as an extension wrapping the corner, most wraparounds on London terraces fall outside permitted development and need a householder planning application. A Lawful Development Certificate is worth pursuing only where each element clearly meets its own limits.
What changes in Hounslow
The side element is not permitted development in a conservation area, so a wraparound there always needs planning permission, designed to the area's appraisal.
The local constraints that most often decide the route in Hounslow are listed below, taken from our Hounslow area page. Each one is a reason to confirm the address on Hounslow's constraints map before relying on permitted development.
- Conservation areas. Hounslow has numerous conservation areas, concentrated in Chiswick (including Bedford Park, Strand-on-the-Green and Chiswick House), Brentford and Old Isleworth. Source
- Article 4 directions. Bedford Park has long-standing Article 4 directions removing permitted development rights for external alterations, so even minor changes to windows, roofs and front gardens need permission.
- Thames flood zones. Land close to the Thames at Chiswick, Brentford and Isleworth falls within Flood Zones 2 and 3. Source
- Green Belt and Metropolitan Open Land. Osterley Park, parts of Hanworth, Cranford and the Duke of Northumberland's River corridor are Green Belt or Metropolitan Open Land.
What Hounslow planning officers look for
Hounslow generally follows the London-wide conventions for householder extensions: single-storey rear extensions of 3 to 4 m are usually acceptable where they respect the 45-degree rule to neighbours' windows, and refusals most often cite excessive depth, loss of daylight or bulk in two-storey schemes. In Chiswick's conservation areas officers expect traditional materials and resist front dormers and boxy roof extensions. Pre-application advice is available for a fee and is worth using for anything in Bedford Park or on the riverside.
Fees and timelines
Hounslow 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
- 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 Hounslow: planning: the council's own constraints map, validation checklist and pre-application service.
