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Guildford · Loft conversion · Checked 30 Oct 2026

Do I need planning permission for a loft conversion in Guildford?

Short answer

Often not. A rear dormer adding no more than 40 m³ of roof volume on a terraced house, or 50 m³ on a semi-detached or detached house, set back from the eaves and below the ridge, is normally permitted development; front dormers, larger volumes and any loft to a flat need planning permission. In a conservation area roof extensions always need planning permission. Guildford has conservation areas and Article 4 directions that remove some permitted development rights, so we check the address on Guildford's constraints map before advising a route.

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Loft conversions 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 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 Guildford

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 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

In Onslow Village and Charlotteville the character appraisal drives decisions on materials, roof form and frontages. 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. The council offers a paid pre-application service.

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).

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Primary sources

02Questions

Loft conversions in Guildford: common questions

How is the 40 m³ or 50 m³ measured?

It is the volume added beyond the original roof slope, including any earlier roof extensions, not the floor area of the new room. We calculate it on the drawings and include the calculation in the Lawful Development Certificate application.

Can I have a front dormer?

Not under permitted development: nothing may extend beyond the plane of the roof slope facing a highway. Front rooflights are fine. A front dormer needs planning permission and most councils refuse them unless the street already has them.

Do I need Building Regulations approval as well?

Yes, always. Permitted development and planning permission concern what you may build; Building Regulations govern how it is built, including the new floor structure, the stair, fire escape and insulation. We prepare that package after the planning route is confirmed.

How long does Guildford take to decide?

The statutory period is 8 weeks from validation for both a householder application and a Lawful Development Certificate, and 42 days for a larger home extension prior approval. Decisions can run past the statutory 8 weeks; allow 8–12 weeks.

03Examples

Example projects that face these questions

Proposed loft floor plan for an L-shaped rear dormer loft conversion on a Victorian terrace in HackneyExample project
Loft conversionStoke Newington, Hackney

Loft Conversion in Stoke Newington, Hackney

L-shaped rear dormer loft conversion to a two-storey Victorian terrace, adding a double bedroom and en-suite within the 40 m³ permitted development allowance.

Typical route: Permitted development, proved with a Lawful Development Certificate

Proposed loft floor plan for a hip-to-gable and rear dormer conversion to an Edwardian semi in TwickenhamExample project
Loft conversionTwickenham, Richmond

Loft Conversion in Twickenham, Richmond upon Thames

Hip-to-gable roof extension with a rear dormer to an Edwardian semi-detached house in a Twickenham conservation area, creating a master bedroom and bathroom in the roof.

Typical route: Householder planning application in an Article 4 conservation area

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Planning a loft conversion in Guildford?

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