Side extensions in Guildford depend on the house. Typical homes here: Victorian and Edwardian terraces and villas around Guildford town centre and in Charlotteville; 1930s semi-detached houses in Stoughton, Burpham and Merrow. Designations to check first: Green Belt; Surrey Hills National Landscape; Conservation areas and Article 4 directions. Applications are decided by Guildford Borough Council and the Guildford Borough Local Plan: Strategy and Sites 2019 and Development Management Policies 2023.
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 Guildford
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 Guildford are listed below, taken from our Guildford area page. Each one is a reason to confirm the address on Guildford's constraints map before relying on permitted development.
- Green Belt. Most of the borough outside Guildford town and the larger villages is Green Belt, including land around Shalford, Send, Ripley, East Horsley and Effingham. Source
- Surrey Hills National Landscape. The Surrey Hills National Landscape (formerly the Surrey Hills Area of Outstanding Natural Beauty) covers the downs and wooded slopes south and east of the town, including land around Shalford, the Horsleys and Effingham. Source
- Conservation areas and Article 4 directions. Guildford town centre, Charlotteville and Onslow Village are conservation areas, and many of the villages, including Shalford, Ripley, Send, East Horsley and Effingham, have designated centres. Source
- Thames Basin Heaths Special Protection Area. The heathland around Ash and the north-west of the borough forms part of the Thames Basin Heaths Special Protection Area. Source
- River Wey flood risk. The River Wey and the Wey Navigation run through Guildford town centre and on through Shalford, Send and Ripley, and land alongside them sits in Flood Zones 2 and 3. Source
- Listed buildings. Guildford town centre, Shalford, Ripley, Send, the Horsleys and Effingham contain many listed houses, cottages and churches. Source
What Guildford planning officers look for
Guildford Borough Council officers assess householder applications against the Local Plan: Strategy and Sites, the Development Management Policies and the council's supplementary guidance on residential extensions. On the 1930s semis in Stoughton, Burpham and Merrow 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. In the Green Belt and the Surrey Hills 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 on village plots.
Fees and timelines
Guildford 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.
- Guildford Borough Council: planning: the council's own constraints map, validation checklist and pre-application service.
