Jan 18, 2026
Planning permission for home extensions gets refused more often than you might expect. Loss of light, overbearing impact, and loss of privacy are the three main reasons local planning authorities turn down extension applications.
These issues can turn a sensible project into a failed planning application, wasting time and money.
Understanding why extensions get refused helps you dodge the same pitfalls. If your extension blocks too much light from a neighbour’s window, feels overbearing, or lets you peer into someone’s private space, planners will usually say no.
These rules protect the living conditions of people living nearby.
Key Takeaways
Loss of light, overbearing impact, and loss of privacy account for most extension refusals in the UK.
Planning authorities use tests like the 45-degree rule and 25-degree rule to see if your extension harms neighbours.
You’ll boost your application’s chances by understanding these guidelines and designing your extension to fit local planning policies.
Understanding Planning Permission and Refusals
Planning permission is a legal must for most building work that changes a property’s size or use. Local planning authorities check applications against their policies and refuse anything that doesn’t measure up.
What Constitutes a Planning Application
A planning application is a formal request to your local authority to do building work or change how you use a property. You need it for extensions, new buildings, and big alterations that go beyond permitted development rights.
You’ll need to submit drawings, site plans, and a description of the work. The council looks over these to see if your plans fit local planning policies and national rules.
Most applications follow a set process. The council makes your proposal public, neighbours can comment, and planning officers weigh your submission against policy before deciding.
Main Reasons for Refusal
Planning refusal happens when your plans clash with policies or harm neighbouring properties. The most common reasons are loss of light, overbearing impact, and privacy concerns.
Loss of light comes up when your extension blocks daylight to someone else’s windows or garden. Authorities use tests like the 25-degree rule and Vertical Sky Component to check this.
Overbearing impact means your development feels too big, too close, or just plain overwhelming for neighbours. If your extension creates a looming presence, it might get rejected.
Privacy issues pop up when new windows or raised structures give you direct views into someone’s home or garden. Officers look at window distances, viewing angles, and whether you can see into private spaces.
Role of Local Planning Authority and Policies
Your local planning authority checks applications against local policies and the National Planning Policy Framework. These rules set standards for height, distance from boundaries, and impact on neighbours.
Planning officers have to assess how your proposal affects others nearby. They look at design standards, whether your extension fits the area, and if it protects neighbour amenity.
Policies can vary by council, but most set guidelines for spacing, height, and minimum garden sizes. Your application needs to show it follows these rules.
Loss of Light: Key Grounds for Extension Refusal
Extensions often fail planning approval if they block too much natural light from neighbouring homes. Planning authorities use technical standards to assess overshadowing and consider complaints about daylight loss.
Overshadowing and Daylight Issues
Overshadowing happens when a new extension blocks natural light from getting to your neighbour’s windows or garden. Planning authorities start with the 25° rule. If your extension breaks a 25° line drawn upwards from the centre of a neighbour’s lowest window, it usually needs a closer look.
The Vertical Sky Component (VSC) is a more detailed check. It measures how much sky you can see from the centre of a window. A VSC of 27% or more is considered good. If your extension drops the VSC below 27% and by 20% or more from what’s there now, the light loss stands out and could mean refusal.
Large rear or side extensions near boundaries cause the biggest headaches. They can block morning or evening sun, cast long shadows over gardens, and make terraced homes feel boxed in.
Right to Light Legal Considerations
Right to light is a separate legal thing from planning permission. It protects your access to a basic level of daylight through existing windows. It doesn’t guarantee sunlight, just enough natural light.
Planning authorities can’t rule on legal rights to light, but they must consider how an extension affects daylight and sunlight under planning policies. If you want to object, focus on how the extension fails planning standards—not just legal rights.
If you lose a lot of light and the council still approves the extension, you might have a legal case. Courts can sometimes stop the build or force changes if the light loss is bad enough.
Daylight and Sunlight Assessments
Councils may ask for a daylight and sunlight assessment if someone wants to build a big extension. This technical report checks how neighbouring properties will be affected using set standards. It looks at both daylight and direct sun.
If your neighbour’s application doesn’t include this, you can prepare your own to back up your objection. A professional assessment carries weight. Sometimes, just pointing out that the basic tests aren’t met will push the council to ask for a full report from the applicant.
This way, you might avoid paying for a full report but still make your point.
Neighbour Objections About Light
Stick to planning grounds in your objection, not personal gripes. Spell out which windows will lose light, when during the day, and how it affects key rooms like kitchens or living rooms.
Photos showing current light levels help. Explain how the extension’s size and position will change things. Reference your local plan’s policies on residential amenity and national planning guidance. If several homes are affected, mention it—broader impacts add weight.
Objections from chartered town planners tend to get more attention. Over 60% of professionally written objections lead to refusals, withdrawals, or changes. Keep your objection clear, based on evidence, and tied to planning policy—not just general complaints.
Loss of Privacy and Overlooking Concerns
Privacy problems crop up when extensions let neighbours see straight into your home or garden. High-up windows, balconies, and terraces can all cause overlooking that makes your place feel exposed.
Overlooking Windows and Private Spaces
Overlooking happens when a new build gives a direct view into your windows or garden. First-floor windows are usually the main culprit. They can look right into bedrooms or living rooms.
Side windows facing your property are especially problematic. They often have sightlines that ground-floor windows don’t. Dormer windows in the roof can also peek into gardens or back rooms.
Your outdoor spaces matter too. Planners check if extensions will let neighbours see into your garden, patio, or seating areas. The closer a new window is to your boundary, the bigger the issue.
To object based on privacy, point out exactly which windows or spaces are affected. Photos showing the view can help.
Design Measures to Protect Privacy
Councils often ask developers to tweak designs to fix overlooking. Obscured glass in bathrooms or landings stops direct views but still lets in light. High-level windows above eye height help too.
Privacy screens or panels can block views from balconies or raised areas. Some windows are angled away from neighbours. Tall fences or hedges take years to grow, so councils don’t always accept them as a quick fix.
Planning authorities try to balance the applicant’s needs with your privacy. They look at window distances and whether the overlooking is worse than before. Changing window positions or sizes can often solve privacy problems without killing the whole project.
Balconies, Terraces, and Elevated Views
Juliet balconies, roof terraces, and walk-on flat roofs let people stand and look down into your property. These spots cause more overlooking than normal windows because people can move around and linger.
Raised patios and tall decking near boundaries are another privacy problem. Even at ground level, a raised platform can let people see over your fence. Planners take these outdoor spaces seriously because they affect your enjoyment of your home.
Inspectors sometimes refuse plans where balconies would create too much overlooking. The visual impact matters as well. Large terraces can feel intrusive, even if they don’t give a direct view inside.
Overbearing and Dominant Design
Extensions that loom over or crowd neighbouring properties—because of their height, bulk, or closeness—often get refused for overbearing impact. Planning authorities look at whether a development harms the character of the area or neighbour amenity because of its scale.
Overbearing Impact on Neighbours
Overbearing impact shows up when an extension feels like it dominates next door. This can happen if it’s too tall, too bulky, or built right up to the boundary. It can make neighbours feel boxed in or overshadowed.
Planning officers check how your extension relates to nearby properties. A two-storey rear extension right on the boundary might feel oppressive, even if it technically passes light rules. The physical presence matters a lot.
Key things planners look at:
Height and size compared to neighbouring homes
Distance from shared boundaries
Loss of outlook from neighbours’ windows
The feeling of being boxed in
One inspector refused extra storeys on a block of flats in Kingston-upon-Thames because the addition felt awkwardly tall and overbearing next to neighbours. It just didn’t fit.
Scale, Character, and Context
Your extension needs to fit the area’s scale and character. Poor design quality that ignores local style often gets rejected.
Councils check if your proposal matches typical building heights, roof shapes, and architectural details. If your extension towers over bungalows or adds a bulky modern look to a Victorian terrace, it might not pass.
They consider:
Usual building heights on your street
Roof shapes and styles
Materials and details
Spacing between homes
Design quality isn’t just about looks. Extensions should show good design that fits the setting. A flat-roofed box on a pitched-roof semi often fails because it clashes with the area.
Mitigation Strategies for Overbearing Extensions
You can reduce overbearing impact by adjusting your design. Try stepping back upper floors from boundaries to shrink the bulk. This gives a bit of breathing room and feels less enclosing.
Roof design helps too. A hipped or pitched roof looks less dominant than a flat roof at the same height. Even lowering the eaves or ridge by half a metre can make your extension feel lighter next to neighbours.
Some good fixes:
Move the extension further from boundaries
Reduce height or width
Use materials that blend in
Break up big blocks with changes in the building line
Drawings that show your extension next to neighbours help prove you’ve thought about the area. Include street views to show how your design fits in.
Policy, Compliance, and Special Restrictions
Extensions have to meet more than just basic planning rules. Knowing about permitted development rights, local frameworks, and boundary law can make or break your project.
PlanSure identifies property-specific red flags before you apply.
Permitted Development and Limitations
Permitted development rights let you build certain extensions without planning permission, but the rules are strict. For single-storey rear extensions, you can go up to 3 metres for attached houses and 4 metres for detached houses.
If you want a two-storey or side extension, you’ll almost always need full planning permission. The General Permitted Development Order spells out the conditions you have to meet—maximum heights, how close you are to boundaries, and what materials you use.
If your extension goes beyond these limits, you’ll need to apply for planning permission. Class A of Part 1 to Schedule 2 holds most of the key permitted development rules for house extensions.
Some areas take away these rights through something called an Article 4 Direction. If you’ve already extended your house, those previous additions count towards your permitted development allowance and could limit what you can do next.
Local Development Plans and Conservation Areas
Your local development plan sets the ground rules for what kinds of extensions are allowed. These policies cover things like design, how much space you need between houses, and the effect on neighbours.
Council planners check your application against these local policies. If you’re in a conservation area, expect tougher restrictions to protect the historic character.
You’ll probably need planning permission for extensions that might be allowed elsewhere. Local planning authorities look closely at designs to make sure they fit the area’s special character.
If your house is listed, you’ll need listed building consent as well as planning permission for most changes. Local plan documents give detailed advice on extension size, materials, and design, so it’s worth checking your council’s website before you start.
Party Wall and Boundary Implications
The Party Wall Act 1996 covers work on shared walls or boundaries. It’s a separate process from planning permission.
If your project affects a party wall, builds right on the boundary, or digs near a neighbour’s foundations, you have to notify the adjoining owners first. Party wall procedures run alongside planning law, not instead of it.
Even if you get planning permission, you still need your neighbours’ party wall consent. If you skip this step, your neighbour can get an injunction to stop the work, and you might be liable for damage.
Building near boundaries means you need to think about both party wall rules and planning policies. Most councils set minimum distances from boundaries for extensions.
Talking to neighbours early on can help you avoid arguments that might otherwise stall your project.
Other Common Grounds for Planning Refusal
Besides overshadowing, overbearing impacts, and privacy issues, councils often refuse extensions because of site density, environmental risks, or traffic safety. These issues usually need specific documents and proof that you meet local planning rules.
Overdevelopment of the Plot
Overdevelopment happens when you leave too little garden or outdoor space after building your extension. Councils look at whether your design keeps enough amenity space and fits the character of the plot.
Most councils have rules about how much garden you have to keep—often 50-60% of the original plot, but it varies. Check your council’s design guide for the exact numbers.
Common overdevelopment issues include:
Too much building, not enough usable outdoor space
Extensions that look squeezed in or cramped
Loss of greenery and natural drainage
Not enough room for bins, bikes, or utilities
Go over your site plans to make sure you keep enough space. Work out what percentage of your plot is covered before and after the proposed work to show you’re following local rules.
Environmental and Flood Risk Factors
If your site is in a flood zone or has ecological features, your planning application will get extra scrutiny. Your extension can’t make flooding worse for you or your neighbours.
If you’re in Flood Zone 2 or 3, you’ll need a flood risk assessment. This proves your project won’t increase flood risk and shows any steps you’re taking to reduce it.
You can check your flood zone status on the planning portal website.
Environmental concerns that can lead to refusal include:
Removing protected trees or hedgerows
Harming bat roosts or bird nesting sites
More surface water runoff with no drainage solution
Pollution from building work affecting habitats or waterways
Sometimes, you’ll need to use sustainable drainage systems (SuDS) like permeable paving, soakaways, or even green roofs to deal with rainwater.
Highway Safety and Access Issues
Extensions that mess with parking, visibility, or access for vehicles often get refused. Councils want to be sure your plans won’t make things dangerous for drivers, cyclists, or pedestrians.
If your extension adds bedrooms or changes how you use your driveway, you may need a transport statement. This explains parking and any traffic impacts.
Your plans should show there’s enough turning space so cars can come and go without backing onto busy roads.
Highway safety problems include:
Taking away parking spaces and not replacing them
Blocking sight lines at junctions
Driveways so narrow they force awkward reversing
More traffic on streets that can’t handle it
Measure your driveway and compare it to your council’s parking standards. A standard parking spot is 2.4m wide by 4.8m long, plus extra for turning.
Strengthening Your Application and Responding to Objections
A solid application with professional guidance and clear evidence can deal with concerns before they become formal objections. Talking to neighbours and responding to their feedback can help avoid delays.
Working with a Planning Consultant
A planning consultant knows local planning policies and national rules inside out. They can review your proposal before you submit anything and spot potential problems, like loss of light or privacy.
Consultants put together detailed documents showing how your plans meet policy. This could include site plans, design statements, or impact assessments.
They know exactly what planning officers want to see. A consultant frames your case in planning terms, not just personal preference, which tends to carry more weight.
If objections come up, a consultant can draft formal responses that address the issues with evidence and policy references. Honestly, this approach often gets better results than trying to handle everything yourself.
Effective Use of Evidence and Assessments
Daylight and sunlight assessments give technical proof that your extension meets standards. These use the 25-degree rule and Vertical Sky Component (VSC) measurements to show neighbouring homes keep enough light.
Include:
Accurate site plans with distances between properties
Shadow studies for different seasons
Photos from neighbours’ perspectives showing current conditions
Cross-sections showing building heights and separation
Professional assessments can back up your case, even if neighbours say otherwise. If you do find a problem, you can tweak your design before the council refuses it.
Clear, scaled drawings help planning officers understand the real impact, not just what neighbours claim. Show window positions, boundaries, and building heights for objective evidence.
Responding to Neighbour Feedback
Answer objections in writing to the planning authority. Stick to planning issues, not personal disputes or property values.
Use specific evidence to counter claims about loss of light or privacy. If someone’s worried about overlooking, explain your window positions, use of obscure glazing, or any privacy screens.
You can offer changes to address real concerns, like adding a privacy screen, moving a window, or lowering the roof a bit. Sometimes, that’s all it takes to resolve an objection.
It’s usually worth speaking to neighbours before you apply. If they know what you’re planning, they might not object—or at least you can deal with their concerns early.
Frequently Asked Questions
Planning authorities refuse extensions for a bunch of reasons—light, privacy, and overbearing impact come up a lot. Knowing these rules helps you design something the council’s likely to approve.
What are the common grounds for refusal of building extensions regarding neighbours' light access?
Planning authorities use the 25-degree rule to check for light obstruction. If your extension blocks a 25-degree line drawn up from the centre of your neighbour’s lowest window, the council will ask for a more detailed assessment.
The Vertical Sky Component (VSC) gives a precise measure of light loss. A window needs at least 27% VSC for good light. If your extension drops a neighbour’s VSC below 27% and cuts it by 20% or more, that’s usually a deal-breaker.
Councils also look at how extensions affect daylight and sunlight in main rooms like kitchens, living rooms, or bedrooms. Losing light in these spaces is a bigger problem than in, say, hallways.
How can a proposed extension affect neighbouring properties' right to privacy?
New windows that look straight into neighbouring gardens or main rooms raise privacy concerns. Councils measure the distance between your windows and the boundaries to judge the risk.
Extensions with balconies, terraces, or raised outdoor spaces get extra attention. These features give views you wouldn’t get from ground-level windows.
If you build a first-floor extension too close to a boundary, neighbours might feel like they’re always being watched. Councils might insist on obscure glass for bathrooms or landings, but they’ll refuse if living room or bedroom windows cause obvious privacy loss.
What regulations govern the impact of property extensions on surrounding buildings?
Local planning authorities follow guidance from the Building Research Establishment for daylight and sunlight. These technical documents set out the calculations planning officers use.
Your local plan has policies on amenity, character, and design. These cover things like minimum distances, maximum heights, and what’s acceptable for neighbours.
The National Planning Policy Framework (NPPF) says councils have to make sure developments offer good amenity for everyone. Planning officers need to show they’ve considered neighbour impacts before saying yes.
In what ways can an extension be considered overbearing to adjacent properties?
Overbearing impact is about the size and closeness of your extension to neighbours. If it feels dominant or oppressive, that’s a red flag.
Height and mass count more than floor area. A two-storey extension near a boundary feels a lot more overbearing than a single-storey one.
Planning inspectors look at whether your extension creates an uncomfortable relationship with the neighbours’ homes. If it’s much taller, deeper, or wider than is typical for your street, you might have a problem.
How close your extension is to your neighbour’s windows or garden matters too. If it’s right outside their main living room window, expect more scrutiny.
What measures can be taken to mitigate potential privacy and light issues when planning an extension?
Setting your extension back from the boundary helps with both light and privacy. Even an extra metre can make a big difference.
Position windows so they don’t look directly into neighbouring homes or gardens. Side-facing windows along boundaries usually cause fewer problems.
If you reduce the height or depth, you might still get the space you need and meet planning rules. Some people win appeals by submitting a revised design that fixes the issues.
Consider roof lights instead of normal windows to bring in light without overlooking. High-level windows with sills above 1.7 metres stop direct views.
You can get a Daylight and Sunlight Assessment before you apply. This report shows you’ve considered the impacts, which can help avoid refusals based on shaky objections.
PlanSure identifies property-specific red flags before you apply.
How does the 'right to light' influence planning permission decisions for extensions?
Right to light is a legal issue, not part of planning permission. Still, councils have to think about how much daylight and sunlight an extension blocks.
You don't actually have a legal right to direct sunlight. But planning policy does try to protect a reasonable amount of natural light for everyone.
Planning authorities won't turn down an application just because a neighbor claims a right to light. If your extension seriously reduces light and fails the VSC test or the 25-degree rule, though, the council might refuse permission.
Councils sometimes ask for technical reports that show how your extension affects your neighbors' light. If you can't show the impact is acceptable, the planning officer will probably recommend refusal—no matter what legal claims about right to light exist.
The two issues—planning permission and right to light—aren't the same. Planning permission looks at general amenity, while right to light is about specific legal limits.
You could get planning permission and still face a legal claim about right to light later. It’s a bit of a headache, honestly, and worth thinking about before you get too far.