What Can You Build Without Planning Permission?

Most home improvements in England don't need planning permission. Rear extensions, loft conversions, porches, garden rooms, fences, solar panels — all of these can be built under "permitted development" rights, within specific limits. Exceed those limits, and you need a full planning application.

The problem is that the limits are confusing. They vary by house type, by location, and by what your neighbours have already built. Get it wrong and your council can force you to tear it down.

This guide covers every major project type. For each one, we explain the permitted development rules — and then show you what actually happens when people do apply for planning permission, using real data from over 2 million decisions across 226 UK councils.

The Quick Reference: What Needs Permission and What Doesn't

Here's the overview. Every project type, whether it typically needs permission, and what the approval rate looks like when it does.

Two things jump out. First, the project types that are most commonly permitted development (porches, conservatories) also have the highest approval rates when they do need permission. Second, the types that always need permission (two-storey extensions, annexes, change of use) cluster at the bottom — between 79% and 83%.

That's not a coincidence. The projects that councils allow without permission are the ones they're most relaxed about. When you're applying for something outside permitted development, you're already in trickier territory.

Check what gets approved near your postcode →

Rear Extensions Without Planning Permission

Rear extensions are the UK's most popular home improvement — and most of them don't need planning permission. Under permitted development, you can build a single-storey rear extension subject to these limits:

Go beyond these limits and you need a full planning application. Our data shows 405,216 rear extension decisions where people did apply — with an 83.0% approval rate. That means roughly 1 in 6 rear extension applications get refused.

The most common reasons for refusal? Overbearing impact on neighbours, loss of light to adjacent properties, and extensions that are disproportionate to the original house.

Real rear extension decisions from our data

The pattern is clear: simple, single-storey rear extensions sail through. The moment you combine a rear extension with a front addition or a first-floor element, the risk jumps significantly.

Full guide: rear extension planning permission →

Loft Conversions Without Planning Permission

A loft conversion can add a bedroom, a bathroom, and tens of thousands in value — and many don't need planning permission. The key factor is which way the dormer faces.

When people do need to apply — typically for front dormers, oversized conversions, or properties in conservation areas — our data shows 146,320 loft conversion decisions with an 83.9% approval rate.

Front dormers are where most refusals happen. Planning officers are protective of streetscapes, and a box dormer on a Victorian terrace that has no existing dormers is a hard sell. Pitched or hipped dormers that match the existing roof design fare significantly better.

Real loft conversion decisions from our data

Porches Without Planning Permission

Porches are one of the easiest things to build without planning permission — and when they do need it, they're almost never refused.

That's it. Three rules. Meet all three and you don't need permission. Our dataset shows 20,548 porch decisions — those that did need an application — with a 90.6% approval rate. Porches are about as low-risk as planning applications get.

Garden Rooms, Offices, and Outbuildings

Garden offices boomed during Covid and haven't slowed down. The good news: most qualify as outbuildings under permitted development.

The "not self-contained living accommodation" rule is where people get caught. A garden office is fine. A garden room for yoga is fine. A garden building with a bed, a kitchen, and a bathroom that you rent out on Airbnb is not fine — that's a material change of use and needs planning permission.

When garden buildings do need permission, our data shows 52,101 decisions with an 84.3% approval rate. The main refusal reasons are excessive size, impact on neighbours' amenity, and use as separate accommodation.

Check garden building approvals near you →

Conservatories Without Planning Permission

Conservatories follow the same permitted development rules as single-storey rear extensions. They're one of the most reliably approved project types — 20,987 decisions in our dataset with a 92.0% approval rate.

The only real risk is if you're in a conservation area (where rear extensions need permission), or if the conservatory is unusually large and triggers neighbour objections about overshadowing.

Side Extensions

Single-storey side extensions can be permitted development — but the rules are tighter than for rear extensions.

Two-storey side extensions are never permitted development — they always need planning permission. Our data shows 82,656 side extension decisions with an 84.8% approval rate. The most common refusal reason is the "terracing effect" — when a side extension fills the gap between semi-detached houses, creating the appearance of a terrace.

Full guide: side extension planning permission →

Two-Storey Extensions: Always Need Permission

There's no permitted development route for two-storey extensions. You always need planning permission.

Two-storey extensions have one of the lower approval rates in our dataset at 82.9%. That means roughly 1 in 6 gets refused. The extra height means more impact on neighbours — more overshadowing, more overlooking, more visual bulk. Councils apply stricter tests around the "45-degree rule" for light and the impact on the streetscene.

Our single-storey vs two-storey analysis breaks down the gap in detail.

Front Extensions: Rarely Permitted Development

Front extensions are the riskiest extension type. They're almost never permitted development (the front of your house faces the highway, so the PD exemption for rear-only extensions doesn't apply), and they change the appearance of the property as seen from the street.

Our data shows 20,106 front extension decisions with an 83.0% approval rate. That's the joint-lowest for extension types. Refusals almost always cite impact on the streetscene and character of the area.

We've written a full analysis of why front extensions get refused — including what designs actually get approved.

Solar Panels Without Planning Permission

Solar panels on your roof are permitted development in most cases. You don't need planning permission unless:

• You're in a conservation area, AONB, or World Heritage Site and the panels would face the highway
• The panels protrude more than 200mm from the roof surface
• The panels would be higher than the highest part of the roof (excluding chimneys)
• Your property is listed

When permission is needed, 21,058 solar panel decisions show an 88.2% approval rate. Refusals are concentrated in conservation areas and on listed buildings where officers consider the visual impact unacceptable.

Fences, Walls, and Gates

Fences and walls are permitted development if they're no more than 2 metres high (or 1 metre if next to a highway). Gates follow the same rules.

When permission is needed — typically for taller fences or boundary walls in prominent locations — 86,212 decisions in our dataset show an 86.8% approval rate.

Dropped Kerbs

Creating a new vehicle crossover (dropped kerb) requires approval from your highways authority, not planning permission. However, if you need to pave over your front garden to create the driveway, you may need planning permission for the hardstanding unless it's permeable paving.

Our dataset shows 16,851 dropped kerb-related decisions with an 80.0% approval rate — one of the lower rates, often because the access raises safety concerns or the council is protecting on-street parking.

Where Permitted Development Doesn't Apply

All of the permitted development rights above can be removed or restricted. You have fewer PD rights — or none at all — if:

If any of these apply to you, always check with your council before building. A Lawful Development Certificate (about £103) gives you legal confirmation that your project is permitted development.

What Happens If You Build Without Permission

If you build something that needed planning permission and didn't get it, your council can issue an enforcement notice requiring you to demolish the work or restore the property to its original state. This isn't theoretical — it happens.

You can apply for retrospective planning permission, but there's no guarantee it'll be granted. And if enforcement action is already underway, you're in a weaker negotiating position.

The time limits for enforcement are 4 years for building works and 10 years for changes of use. After these periods, if no enforcement action has been taken, the development becomes lawful. But relying on the time limit is a risky strategy — we've written more about this in our guide to building without planning permission.

Where People Get Caught Out

The permitted development rules above look straightforward on paper. In practice, people get tripped up by the same handful of issues:

• Conservation areas. PD rights are drastically reduced. Rear dormers, side extensions, and cladding that would be fine elsewhere all need permission. Many homeowners don't even know they're in a conservation area until they get an enforcement letter.
• Article 4 directions. Your council can strip PD rights from specific streets or areas. Common in historic town centres and for HMO conversions. There's no central register — you have to check with your council.
• Flats and maisonettes. Almost no PD rights. If you live in a flat, assume you need permission for any external change.
• Previous extensions eating your allowance. The PD limits are cumulative. If a previous owner built a 3m rear extension, that's 3m of your allowance already used. If they added a rear dormer, that volume counts against your 40/50m³ roof limit.
• Assuming "no one will notice." Neighbours report unauthorised development. Councils investigate. Enforcement notices get issued. The 4-year rule is not a strategy — it's a last resort.

What This Means For You

Here's the practical takeaway. Before you build anything:

1. Confirm your PD rights still apply. Are you in a conservation area? Has an Article 4 direction removed your rights? Has a previous owner already used part of your allowance? If you're unsure, a Lawful Development Certificate (£103) gives you legal certainty.
2. If you need planning permission, check what's been approved nearby. National approval rates are useful benchmarks, but your odds depend on your street, your ward, and your council's policies. An approved extension three doors down is your strongest evidence.
3. Keep it simple. The data is clear: straightforward projects (single-storey rear extensions, porches, conservatories) have the highest approval rates. The moment you combine multiple elements or push the scale, refusal rates climb.
4. Research before you spend. Architect drawings cost £1,500–£4,000. A planning application costs £258. A refused application means both are wasted. Ten minutes checking what your council actually approves in your area is the cheapest insurance available.

The Bottom Line

Most common home improvements — rear extensions, rear dormers, porches, garden rooms, conservatories, solar panels, fences — can be built without planning permission under permitted development, subject to specific limits.

When you do need to apply, the approval rates range from 80% to 92%, depending on the project type. The projects that councils are most relaxed about (porches, conservatories) have the highest rates. The ones that push boundaries (two-storey extensions, front extensions, annexes) sit lower.

But these are national averages. Your odds depend on your council, your ward, and what's been approved nearby. A project that sails through in one borough might get refused in the next.