Most Common Planning Applications in the UK

What are UK homeowners actually applying for planning permission to build? We have the data to answer that definitively.

PlanningLens has analysed over 2,500,000 planning decisions from 226 councils across England and Wales. By categorising each application by project type, we can show you exactly which types of work generate the most planning activity — and how likely each is to succeed.

The Full Ranking

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Rear Extensions: The Nation's Favourite Project

It's not even close. Rear extensions account for more planning decisions than any other single project type — nearly double the next most common category. The classic kitchen-diner expansion remains the UK's go-to home improvement project.

The good news for anyone planning one: rear extensions also have one of the highest approval rates at 90.6%. They're familiar to planning officers, they have strong local precedent on most streets, and their impact on the wider area is minimal because they're at the back of the property.

Many rear extensions don't even need planning permission at all — they fall under permitted development rights. The 186,000 decisions in our dataset represent only those that did require a formal application.

The Garage Surprise

Garages are the second most common application type at 136,603 decisions. This includes new garage builds, garage conversions, and changes to existing garages. The volume reflects how central garages are to UK residential life — and how often homeowners want to modify them, whether that's converting to a home office, building a new one, or replacing an existing structure.

The approval rate of 86.9% is solid but not as high as rear extensions. Garage applications sometimes face resistance when they involve converting the only off-street parking space — highways and parking are common objection points.

Side Extensions: A Close Third

Side extensions account for 102,146 decisions, making them the third most common type. Their 89.8% approval rate is strong, though the "terracing effect" — where a side extension closes the gap between semi-detached houses — is a well-known refusal trigger in some councils.

The volume reflects the popularity of side return extensions in Victorian and Edwardian terraces, particularly in London and the South East. These narrow infill extensions are often combined with rear extensions to create larger open-plan living spaces.

Dormers, Lofts, and Going Up

Dormers (58,175 decisions) and loft conversions (28,968 decisions) together represent a huge volume of applications. Adding upward space is popular because it doesn't consume garden — but it does change the roofline, which is why these project types face more scrutiny than ground-floor extensions.

Dormers have an approval rate of 85.7% — noticeably lower than rear extensions. The gap widens further in councils with strict policies on front dormers or in conservation areas. Our detailed loft conversion analysis breaks this down by council.

The Low-Volume, High-Refusal Types

At the bottom of the volume table are the project types that fewer homeowners attempt — but those who do face the toughest odds.

Flat conversions (3,766 decisions) have the lowest approval rate of any type at just 75.3%. One in four is refused. HMOs (10,481 decisions) are refused at 21.4%. These are the project types where planning permission is a genuine hurdle, not a formality.

By contrast, basements (8,802 decisions) might seem niche but carry a surprisingly reasonable 86.3% approval rate — though this varies enormously by borough, with some London councils having specific basement policies.

Check the approval rate in your council →

What the Volume Data Tells You

High-volume application types are generally safer bets. Not because volume causes approval, but because the same factors that make a project type popular — familiarity, established precedent, lower impact — are the factors that make planning officers comfortable saying yes.

If you're proposing something that your council sees thousands of times a year, like a rear extension, the officer knows exactly what to look for and has a strong framework for approval. If you're proposing something they see rarely, like a basement conversion or an annex, expect more questions and potentially more scrutiny.

This doesn't mean you should avoid less common project types. It means you should do more homework before committing to them — and that homework starts with understanding what your specific council has approved and refused for similar projects.

Your Project, Your Area

National volume and approval data provides the context. But what matters for your project is what's happening in your council and your ward.

PlanningLens analyses 2,500,000+ decisions broken down by council, ward, and project type. Enter your postcode and you'll see approval rates specific to your area — not national averages that smooth over the enormous variation between councils.

The best time to learn this is before you brief an architect. The second best time is now.