Do You Need Planning Permission or Is Permitted Development Enough?

February 2026

If you are thinking about extending, renovating, or reconfiguring your home in London, one of the first questions that usually comes up is whether you actually need planning permission. You may have heard friends or builders say, “It’s fine, it’s permitted development,” while others warn you that you must go through a full planning application. The reality sits somewhere in between.

Understanding the difference between planning permission and permitted development rights can save you time, money, and stress. It can also prevent costly mistakes that only come to light when you try to sell your home or if the council gets involved mid-build. This article is designed to help you make an informed early-stage decision about which route applies to your project, before you get too far down the line.

Planning Permission vs Permitted Development Explained Simply

Planning permission is formal approval from your local authority to carry out a specific type of development. It involves submitting drawings, supporting documents, and waiting for a decision, which can take several weeks or longer.

Permitted development, often shortened to PD, is a set of national rules that allow certain types of work to be carried out without applying for full planning permission. These rights are automatically granted to many homes, as long as the proposed works stay within strict limits and conditions.

In London, where housing stock is varied and space is at a premium, permitted development plays a big role in helping homeowners adapt their properties. However, it is also one of the most misunderstood parts of the planning system.

When Permitted Development Is Usually Enough

For many common home improvements, permitted development is designed to cover exactly the sort of changes homeowners want to make.

Internal Renovations

If your project is entirely internal, planning permission is rarely required. Updating kitchens or bathrooms, rewiring, reconfiguring layouts, or redecorating all fall outside planning control in most cases. Even removing or adding internal walls is generally fine from a planning perspective.

That said, internal works are still subject to building regulations. Structural changes, insulation upgrades, and fire safety measures must meet current standards, regardless of whether planning permission is needed.

Loft Conversions

Loft conversions are one of the most popular home improvements in London, and many can be carried out under permitted development.

As a general rule, loft extensions are permitted if they stay within volume limits. For terraced houses, this is typically up to 40 cubic metres. For detached and semi-detached houses, the allowance usually increases to 50 cubic metres. The extension must not extend beyond the roof slope of the principal elevation that faces the street, and materials should be similar in appearance to the existing house.

Roof height cannot be increased, and side-facing windows usually need to be obscure glazed. While these rules sound straightforward, small design changes can quickly tip a loft conversion out of PD territory.

Rear Extensions

Single-storey rear extensions are often possible under permitted development, which is why so many London homes have added kitchen or living space at the back.

The depth and height limits depend on the type of property. For houses, rear extensions are typically allowed up to three or four metres deep, depending on whether the house is detached or not. Heights are also restricted, particularly near boundaries.

There is also a larger home extension scheme that allows deeper extensions in some cases, but this usually involves a prior approval process with the council. While this is not full planning permission, it is not automatic either.

Garage Conversions

Converting an existing garage into habitable space is often permitted, as long as the work does not involve extending the building or changing its overall use. Many garage conversions are internal alterations, which planning does not usually control.

However, parking requirements, conservation area rules, and previous planning conditions can all affect whether PD rights apply.

When Full Planning Permission Is Required

While permitted development covers a lot, there are clear situations where planning permission is unavoidable.

Listed Buildings and Conservation Areas

If your property is listed, permitted development rights are very limited or removed entirely. Almost all alterations, both internal and external, will require listed building consent, and often planning permission as well.

Conservation areas also come with additional restrictions. While some permitted development rights still apply, they are often reduced, particularly for visible changes such as extensions, roof alterations, or new windows. Many London boroughs have extensive conservation areas, so this is always one of the first things to check.

Extensions Beyond Permitted Limits

If your proposed extension exceeds the size or height limits set out under PD rules, you will need full planning permission. This commonly applies to rear extensions that go deeper than the allowed three or four metres, or side extensions that are wider than half the original house.

Two-storey extensions almost always require planning permission, as do extensions that significantly alter the character of the property.

Major Structural Changes

Adding additional storeys, significantly altering the front façade, or making changes that impact how the building is perceived from the street will usually trigger the need for planning permission.

In dense urban areas like London, councils pay close attention to how development affects neighbours, daylight, privacy, and the overall streetscape. These factors are assessed through the planning process rather than permitted development.

Change of Use

Changing how a building is used often requires planning permission. Examples include converting a single house into flats, turning a commercial property into residential use, or using part of your home for certain business purposes.

Some changes of use are allowed under permitted development, but these are subject to specific criteria and often involve a prior approval application.

London-Specific Considerations You Should Not Ignore

London has its own planning quirks, and these can have a big impact on whether permitted development is enough for your project.

Article 4 Directions

Many London councils use Article 4 Directions to remove permitted development rights in specific areas. This is often done to protect the character of neighbourhoods or manage housing supply.

If your property is in an area covered by an Article 4 Direction, works that would normally fall under permitted development may require planning permission instead. This can catch homeowners out, especially with loft conversions or changes of use.

Always check with your local authority or planning consultant before assuming PD rights apply.

Lawful Development Certificates

While not compulsory, applying for a Lawful Development Certificate, often called an LDC, is strongly recommended when carrying out work under permitted development.

An LDC is formal confirmation from the council that your proposed or completed works are lawful and do not require planning permission. This document can be invaluable if you sell your home in the future or if questions arise about the legality of the works.

Without an LDC, you may struggle to prove that your development was permitted, even if it fully complied with the rules at the time.

Building Regulations Are Separate

One of the most common misconceptions is that permitted development means no approval is needed at all. In reality, planning and building regulations are two separate systems.

Almost all structural work, extensions, loft conversions, and garage conversions require building regulations approval. This covers areas such as structural safety, insulation, ventilation, soundproofing, and fire safety.

Skipping building regulations approval can lead to serious problems, including enforcement action and difficulty selling your property.

Why Early Advice Matters

At the early stages of a project, it can be tempting to rely on online guides or hearsay. While general information is helpful, small details can make a big difference in planning terms.

The age of the property, previous extensions, local planning policies, and even how your house compares to its neighbours can all affect whether permitted development applies. What worked for the house next door may not work for yours.

Speaking to an architect, planning consultant, or experienced designer early on can help you understand your options clearly. This can shape the design from the outset, reducing the risk of delays or redesigns later.

Making the Right Call for Your Project

So, do you need planning permission, or is permitted development enough? For many smaller, rear-facing, or internal projects in London, permitted development can be a straightforward and efficient route. It allows homeowners to improve their properties without the time and uncertainty of a full planning application.

However, PD rights are not a blanket approval. They come with conditions, limitations, and local exceptions that must be carefully checked. Conservation areas, listed buildings, Article 4 Directions, and ambitious designs often push projects into planning permission territory.

The safest approach is to treat permitted development as a legal framework rather than a shortcut. Confirm that your proposals comply, consider applying for a Lawful Development Certificate, and always factor in building regulations.

By understanding the difference early on, you can move forward with confidence, knowing that your project is not only well designed, but also legally sound.

Sources

Do I need planning permission? HomeOwners Alliance, https://hoa.org.uk/advice/guides-for-homeowners/i-am-improving/do-i-need-planning-permission/.

Home renovating: Do I need planning permission? London’s Built Environment Community, Feb 2021. https://nla.london/news/home-renovating-do-i-need-planning-permission.

Planning Permission for Home Renovation, Tango Interiors, https://www.tangointeriors.co.uk/planning-permission-for-home-renovations/. 

Building Regulations in London - Permitted Development VS Full Planning Permission, RoseLinePremier Construction & Design, https://www.roselinepremier.com/articles/building-regulations-in-london-permitted-development-vs-full-planning-permission/.