House Extension Planning Permission
For most extensions, the real job is to separate the national baseline from the measurements, site history and local constraints that decide whether the simpler route still holds up.
Working position
Many house extensions stay on the simpler route only when scale, height, depth, neighbour impact and site history all stay comfortably inside the normal envelope.
What changes it fastest
Depth, height, width, boundary siting, previous additions and heritage controls are the checks most likely to push an extension into a fuller planning route.
Safest next step
Settle the broad rule first, then go local only if the answer still turns on one authority, one restriction or one genuinely borderline measurement.
How To Use This Guide Efficiently
The Broad Planning Position, The Main Tripwires And The Evidence Worth Gathering
What to gather before you spend more
- Measured drawings showing projection, height, roof form and relationship to the original house.
- A note of previous extensions or roof additions that may already have used permitted development allowances.
- Site photos that show frontage visibility, neighbour relationship and any heritage-sensitive context.
Helpful while the route is still broad
The tools are useful for an early steer. Once the project type is clear, the stronger move is usually one good guide and one good local page rather than more browsing.
Thresholds And Practical Checks Worth Treating Seriously
Scale and projection
Rear depth, side width and overall bulk usually decide whether an extension still looks routine.
Use local pages belowNeighbour impact
Loss of light, overbearing effect and awkward boundary siting are where many borderline schemes start to unravel.
Use local pages belowOriginal house baseline
The answer often turns on what counts as the original house and how much earlier development has already changed the position.
Use local pages belowLocal and heritage controls
Conservation areas, listed status and council-specific design expectations can matter more than one headline national rule.
Use local pages belowStart With These Broader Guides Before Going Hyper-Local
These guides deal with the bigger planning questions first, so local pages are only doing the local work they genuinely need to do.
Planning Permission For Extensions
Best for the broad extension route before you narrow down to a subtype.
Open guideBuilding Regulations For Extensions
Helpful when planning and technical approvals are getting mixed together.
Open guideWhat Drawings Do I Need For Planning Permission?
Useful once the extension may be heading toward a formal application or certificate.
Open guideUseful Once The Broad Rule Is Clear Enough To Name
What can I build? Explorer
Use the explorer if you are still choosing between extensions, lofts, outbuildings and other project types.
Explore optionsPlanning decision tool
Use the tool for a first-pass steer before you dive into the local project pages.
Open toolExtension value estimator
Estimate likely value uplift for this kind of project before relying on rough ROI claims or generic rules of thumb.
Estimate valuePlanning route planner
Use the route planner when the live question is which approval path or parallel consent is most likely to matter.
Plan routeProject requirements generator
Use the requirements generator to turn the project into a practical prep pack before drawings or applications move further.
Build prep packPlanning rejection risk analyzer
Use the risk analyzer when you want to see the objections most likely to cause trouble before an application goes in.
Open analyzerBrowse councils first
Choose this route when the local authority or conservation area question matters more than the project type.
Open council hubDo I need planning permission?
Read the core process answer if you are still unsure about the basic planning permission question.
Read answerOfficial Sources Worth Keeping In The Loop
These sources should support the guide above, not replace it. Use them when you need the official baseline or you are close to a formal application decision.
Planning Portal: do you need planning permission?
Use the official starter route when the basic permission question is still unresolved.
Open sourcePlanning Portal: permitted development rights
Use the national baseline when the simpler route may still apply.
Open sourceGOV.UK: before submitting an application
Use the official process guide before paying for a weak application package.
Open sourceFind The Right Local Authority Layer
Go to the area layer once the broad route is clear enough. It matters most where one authority, one heritage context or one local policy culture could change the safer next step.
Bedfordshire
Compare house extension guidance across 3 local authority areas in Bedfordshire, then drill into the right council page.
Compare this areaBerkshire
Compare house extension guidance across 6 local authority areas in Berkshire, then drill into the right council page.
Compare this areaBuckinghamshire
Compare house extension guidance across 2 local authority areas in Buckinghamshire, then drill into the right council page.
Compare this areaCambridgeshire
Compare house extension guidance across 6 local authority areas in Cambridgeshire, then drill into the right council page.
Compare this areaCornwall
Compare house extension guidance across 2 local authority areas in Cornwall, then drill into the right council page.
Compare this areaCounty Durham
Compare house extension guidance across 2 local authority areas in County Durham, then drill into the right council page.
Compare this areaCumbria
Compare house extension guidance across 2 local authority areas in Cumbria, then drill into the right council page.
Compare this areaDerbyshire
Compare house extension guidance across 9 local authority areas in Derbyshire, then drill into the right council page.
Compare this areaDevon
Compare house extension guidance across 10 local authority areas in Devon, then drill into the right council page.
Compare this areaDorset
Compare house extension guidance across 2 local authority areas in Dorset, then drill into the right council page.
Compare this areaEast Sussex
Compare house extension guidance across 6 local authority areas in East Sussex, then drill into the right council page.
Compare this areaEssex
Compare house extension guidance across 12 local authority areas in Essex, then drill into the right council page.
Compare this areaGloucestershire
Compare house extension guidance across 6 local authority areas in Gloucestershire, then drill into the right council page.
Compare this areaGreater London
Compare house extension guidance across 33 local authority areas in Greater London, then drill into the right council page.
Compare this areaHampshire
Compare house extension guidance across 13 local authority areas in Hampshire, then drill into the right council page.
Compare this areaHerefordshire
Compare house extension guidance across 1 local authority areas in Herefordshire, then drill into the right council page.
Compare this areaHertfordshire
Compare house extension guidance across 10 local authority areas in Hertfordshire, then drill into the right council page.
Compare this areaKent
Compare house extension guidance across 12 local authority areas in Kent, then drill into the right council page.
Compare this areaLeicestershire
Compare house extension guidance across 8 local authority areas in Leicestershire, then drill into the right council page.
Compare this areaLincolnshire
Compare house extension guidance across 9 local authority areas in Lincolnshire, then drill into the right council page.
Compare this areaNorfolk
Compare house extension guidance across 7 local authority areas in Norfolk, then drill into the right council page.
Compare this areaNorthamptonshire
Compare house extension guidance across 2 local authority areas in Northamptonshire, then drill into the right council page.
Compare this areaNorthumberland
Compare house extension guidance across 1 local authority areas in Northumberland, then drill into the right council page.
Compare this areaNottinghamshire
Compare house extension guidance across 8 local authority areas in Nottinghamshire, then drill into the right council page.
Compare this areaOxfordshire
Compare house extension guidance across 5 local authority areas in Oxfordshire, then drill into the right council page.
Compare this areaScotland
Compare house extension guidance across 34 local authority areas in Scotland, then drill into the right council page.
Compare this areaShropshire
Compare house extension guidance across 2 local authority areas in Shropshire, then drill into the right council page.
Compare this areaSomerset
Compare house extension guidance across 3 local authority areas in Somerset, then drill into the right council page.
Compare this areaStaffordshire
Compare house extension guidance across 9 local authority areas in Staffordshire, then drill into the right council page.
Compare this areaSuffolk
Compare house extension guidance across 5 local authority areas in Suffolk, then drill into the right council page.
Compare this areaSurrey
Compare house extension guidance across 11 local authority areas in Surrey, then drill into the right council page.
Compare this areaTyne And Wear
Compare house extension guidance across 5 local authority areas in Tyne And Wear, then drill into the right council page.
Compare this areaWales
Compare house extension guidance across 25 local authority areas in Wales, then drill into the right council page.
Compare this areaWarwickshire
Compare house extension guidance across 5 local authority areas in Warwickshire, then drill into the right council page.
Compare this areaWest Sussex
Compare house extension guidance across 7 local authority areas in West Sussex, then drill into the right council page.
Compare this areaWiltshire
Compare house extension guidance across 2 local authority areas in Wiltshire, then drill into the right council page.
Compare this areaWorcestershire
Compare house extension guidance across 6 local authority areas in Worcestershire, then drill into the right council page.
Compare this areaYorkshire
Compare house extension guidance across 16 local authority areas in Yorkshire, then drill into the right council page.
Compare this areaLocal Pages Worth Opening Next
These are practical next reads, chosen to shorten the jump from a broad guide into the local answer rather than send you into another directory trail.
House Extension in Bedford
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideHouse Extension in Central Bedfordshire
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideHouse Extension in Luton
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideHouse Extension in Bracknell Forest
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideHouse Extension in Reading
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideHouse Extension in Slough
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideHouse Extension in West Berkshire
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideHouse Extension in Windsor and Maidenhead
Open a local page that starts with the normal route, then shows the local restriction signals and what to check next.
View local guideTopic Hubs That Matter For This Project Type
Planning Permission
Open this topic hub when the real blocker for house extension is planning permission.
Open topicPermitted Development
Open this topic hub when the real blocker for house extension is permitted development.
Open topicDepth Limits
Open this topic hub when the real blocker for house extension is depth limits.
Open topicHeight Limits
Open this topic hub when the real blocker for house extension is height limits.
Open topic