The permitted development rules for side extensions
A single-storey side extension is permitted development on a house if it is no wider than half the width of the original house, no higher than 4 m, with eaves no higher than 3 m where it comes within 2 m of a boundary, and finished in materials similar in appearance to the house.
Anything wider than half the original house, any two-storey side extension, and any side extension on a flat needs planning permission. Garage conversions that keep the walls are usually permitted development; extending beyond them is assessed as a side extension.
What changes in Woking
Side extensions are not permitted development in a conservation area at all, so there a planning application is always required.
The local constraints that most often decide the route in Woking are listed below, taken from our Woking area page. Each one is a reason to confirm the address on Woking's constraints map before relying on permitted development.
- Green Belt. Green Belt surrounds Woking's urban area, taking in land around Horsell Common, Hook Heath, Pyrford, Byfleet, Brookwood and Mayford. Where planning permission is needed, extensions to houses in the Green Belt must not be disproportionate to the original dwelling, and outbuildings face a stricter test on size, siting and effect on openness. Check the council's constraints map to see whether your plot is inside the boundary. Source
- Thames Basin Heaths Special Protection Area. Horsell Common and the heathland to the north and west of the borough form part of the Thames Basin Heaths Special Protection Area. New dwellings within 400 m of the SPA are normally resisted and those within 5 km usually have to contribute to mitigation. Extensions, lofts and garden rooms to an existing house are usually unaffected, but a new dwelling, an annexe or a flat conversion will need to address the SPA policy. Source
- Conservation areas. Woking's conservation areas include parts of Horsell, Hook Heath, Byfleet, Pyrford and Brookwood Cemetery. Roof extensions are not permitted development inside them, and officers apply the character appraisal to extensions, dormers and boundary treatments. Check the council's constraints map for the exact boundaries before relying on permitted development. Source
- Article 4 directions. Some areas of the borough have Article 4 directions that remove particular permitted development rights, typically for front alterations, roof works or boundary changes in sensitive residential areas. The extent varies street by street, so check the council's constraints map for your address before relying on permitted development. Source
- Basingstoke Canal, River Wey and Bourne flood risk. The Basingstoke Canal runs through the middle of the borough, the River Wey forms the eastern edge through Byfleet and Pyrford, and the Bourne and Hoe Stream cross the west and south. Land alongside them sits in Flood Zones 2 and 3, so ground-floor extensions and outbuildings there may need a flood risk statement with the application. Source
- Listed buildings. Pyrford, Byfleet, Horsell and Old Woking contain listed houses, churches and farm buildings, and Brookwood Cemetery has many listed structures. Listed building consent is needed for almost any alteration, internal or external. Source
What Woking planning officers look for
Woking Borough Council officers assess householder applications against the Core Strategy, the Development Management Policies DPD and the council's supplementary guidance on residential extensions. On the semis in Horsell, Maybury, Knaphill and Byfleet they tend to look for two-storey side extensions set back from the front wall and below the main ridge, a gap kept to the side boundary so the pair does not read as a terrace, and rear extensions that pass the 45-degree test to the neighbour's nearest habitable window. On Hook Heath and in Pyrford the emphasis shifts to plot coverage, tree protection and the spacious, wooded character of the road. In the Green Belt officers usually measure the extension against the original dwelling by floorspace or volume and treat outbuildings more strictly. Common refusal reasons are full-width box dormers, side extensions that create a terracing effect, and disproportionate additions in the Green Belt. The council offers a paid pre-application service. Decisions can run past the statutory 8 weeks; allow 8–12 weeks.
Fees and timelines
The council fee for a householder application is £528 and for a Lawful Development Certificate £264 (England, from 1 April 2025; verify before applying). Both are decided within 8 weeks of validation.
Our own fee for the drawings and the application is fixed once quoted and depends on the project type, its size and the constraints above. Answer six questions in the quote tool and we email you an indicative figure within minutes, then a written fixed-fee quote within 24 hours.
