Permitted Development vs Planning Permission: Advice from Architects London

If you're planning a home extension in London, one of the first questions you'll probably ask is: Do I need planning permission, or can I build under permitted development?

It's a common point of confusion. Many homeowners assume they can start building without approval, only to discover later that their project requires planning permission. Others apply for planning permission when they don't actually need to, adding unnecessary time and costs.

As architects London homeowners trust, we've guided hundreds of clients through this process. Understanding the difference between Permitted Development (PD) and Planning Permission can save you time, money, and a lot of stress.

 What Is Permitted Development?

Permitted Development (PD) allows certain home improvements and extensions to be carried out without submitting a full planning application. These rights are granted by the government, provided your project stays within specific limits and conditions.

Depending on your property, Permitted Development may cover:

• Single-storey rear extensions
• Loft conversions
• Side extensions
• Porches
• Garage conversions
• Rooflights and certain external alterations

However, qualifying for Permitted Development depends on several factors, including your property's location, size, previous extensions, and whether it's in a conservation area.

This is why many residential architects in London recommend checking your eligibility before any design work begins.

 What Is Planning Permission?

Planning permission is formal approval from your local council for developments that fall outside Permitted Development rules.

You'll usually need planning permission if you're planning:

• A large rear extension
• A double-storey extension
• A wraparound extension
• Significant alterations to the front of your property
• Extensions on listed buildings

Work on homes in conservation areas where PD rights are restricted

Projects that exceed height, width, or volume limits

The council reviews how your proposal affects neighbouring properties, the street scene, daylight, privacy, and local planning policies.

When Does Permitted Development Not Apply?

Many London homeowners are surprised to learn that Permitted Development isn't available for every property.

At Extension Architecture, we specialise in helping homeowners navigate every stage of the extension process—from determining whether your project qualifies under Permitted Development to preparing successful planning applications. As experienced architects London homeowners rely on and trusted residential architects in London, our goal is to design beautiful, practical spaces while making the planning process as straightforward as possible. If you're considering extending your home, our team is here to help you move forward with confidence.