Category: Blog

Planning Permission for Extension: What You Need to Know

Home » Blog » Planning Permission for Extension: What You Need to Know


Are you considering building an extension for your home? If so, it’s important to know whether you need planning permission before starting any work. Planning permission is required by law for most extensions, but there are some exceptions. In this blog, we’ll take a closer look at what extensions are and what planning permission entails. We’ll also explore whether you can build an extension without planning permission, how to determine if it’s required, and how to apply for it. We’ll discuss the benefits of engaging an architect or town planner and provide information on the cost of obtaining planning permission. Lastly, we’ll cover what happens if you don’t obtain the necessary planning permission. If you’re looking to build an extension that matches the style of your original house, and need help or advice on planning permission, read on.

Modern Extension

Do you need planning permission for an extension?

Planning permission for homeowners’ extensions in the UK may be required depending on factors like size, location, type and whether there are any planning constraints that limit or removed your permitted development rights. Seeking professional advice from a town planner can help determine if it’s necessary. Compliance with permitted development rights can exempt certain extensions from planning permission. Building regulations still apply even if planning permission is not needed.

What are Extensions?

Extensions refer to additions or enlargements made to an existing property, including building work. They can include single-storey or multi-storey additions, such as rear extensions, side extensions, wrap-around extensions, garden rooms, conservatories, and loft conversions. Single storey extensions are a popular way to enhance living space, accommodate growing families, and create additional rooms. Proper planning and design are essential for successful and functional extensions.

Why is planning permission required for extensions?

Planning permission is necessary for extensions to ensure adherence to local planning policies, including the Local Planning Authority’s (LPA) regulations. It allows for control and regulation, protecting the environment and maintaining the area’s character. Planning permission also considers the impact on neighbouring properties and infrastructure. Obtaining it ensures safe, sustainable, and purposeful extensions.


Can you build an extension without planning permission?

Certain types of extensions and renovation can be constructed without the need for planning permission, such as adding an extension to an existing house. These are known as permitted development rights and allow for minor alterations and additions to a property. However, it must meet all of the required criteria and limitations to qualify for permitted development. Adhering to building regulations is still necessary even if planning permission is not required.

Can extensions be permitted development?

House extensions do have the potential to be considered permitted development. Examples include single-storey rear extensions, loft conversions, and conservatories. However, meeting size limitations, location requirements, and other criteria is crucial. It’s important to consult with the local planning authority or a professional planner to determine if an extension qualifies as permitted development.

Are there any restrictions for permitted development?

Yes, permitted development rights can be restricted or removed by local planning authorities, especially in conservation areas or areas of outstanding natural beauty. Planning conditions imposed on a property, as well as listed buildings and protected areas, may also limit these rights. Additionally, complex or controversial projects may require planning permission despite falling within permitted development rights.

Only houses, including semi-detached houses, can have Permitted Development rights BUT not all houses have permitted development rights. Flats, maisonettes and commercial properties never have permitted development rights, so planning permission is always required. Permitted development rights are always limited so previous developments, even if a long time ago by a previous owner, may have used up some or all of the permitted development allowance for the property.

There can also be planning constraints such as Article 4 direction, conservation area, or even living under a flight path in an area of outstanding natural beauty could have removed your permitted development rights. This means there can be 2 houses, in the same town, doing the exact same project, for example, a 3-meter extension and one could be done under permitted development, while the other needs planning permission even though they are identical.

How to Determine if Planning Permission is Required?

To determine if planning permission is needed for an extension, you can check the permitted development rules via your local council website, the governments planning portal or the General Permitted Development Order. Factors like size, location, and type of extension play a role. Consulting with the local planning authority or a professional planner can provide clarity. Unfortunately there is no one size fits all answer, even if your proposal meets all of the required policies there are other factors to consider including the impact on neighbours and the surrounding area as well as any planning constraints.

Option 1: Submit a Pre-Application to your council

Submitting a pre-application to your local council can be a beneficial first step when seeking planning permission for an extension. You will also This process allows for early feedback and can help identify any potential issues that may arise during the planning permission process, including exemptions. By engaging with the council, you can ensure a clear understanding of their requirements and expectations, including any information provided by the previous owner. Pre-application consultations can also save time and cost by addressing any concerns or changes that need to be made before submitting a formal application. Seeking professional advice from a planning consultant can further enhance this pre-application process.

Pre-Planning Advice

Option 2: Planning By Design can conduct a Planning Appraisal

Engaging the services of a planning consultant, such as Planning By Design, can be highly beneficial when considering an extension. We can provide a comprehensive planning appraisal, evaluating the feasibility and potential issues of your proposed project. Expert advice from a planning consultant can give you an indication of the likelihood of obtaining full planning permission. Additionally, they can assist in developing a robust planning application, increasing the chances of a successful outcome. By utilizing the services of Planning By Design, you are enhancing your chances of obtaining the necessary planning permission for your dream extension.

How to apply for Planning Permission for Extensions?

To apply for planning permission for extensions, you need to prepare architect drawings of your proposed changes. Include existing and proposed elevations, floor plans, block plans, and site location plan. Justify how your proposal meets planning policies and submit a completed application form with supporting documents. Pay the application fee and be ready to negotiate if needed.

What is the benefit of engaging an architect?

Engaging an Architect and a structural engineer for your extension project can offer several benefits. Architects ensure that your plans are feasible and meet building codes. They can help design a functional and aesthetically pleasing extension that meets your needs. Additionally, architects can produce accurate scale drawings to pass the council’s validation process, while a structural engineer can ensure that the extension is structurally sound and meets all necessary safety requirements.

What is the benefit of engaging a Town Planner?

Engaging a Town Planner can be highly beneficial when seeking planning permission for your extension. They offer expert guidance, ensuring compliance with local authority regulations and advising on feasibility. They handle planning applications, including the community infrastructure levy, saving you time and potential legal issues. Working with a Town Planner streamlines the process and maximizes your chances of success.

How Long Does It Take to Get Planning Permission?

The time it takes to obtain planning permission for an extension can vary, but the statutory time frame is 8 weeks for householder applications. Factors such as project complexity and local planning authority workload can affect approval time. Submitting a well-prepared application and allowing 3 to 6 months is recommended. Hiring a professional planner can streamline the process.

What Happens If You Don’t Obtain The Necessary Planning Permission?

If you don’t obtain the necessary planning permission for your extension, you risk receiving an enforcement notice from the local council. This can lead to potential legal repercussions, fines, and the need to undo any unauthorized construction work at your expense. Additionally, not having proper planning permission can potentially devalue your property and cause difficulties in selling or remortgaging it.
Retrospective Planning & Enforcements

How much does Planning Permission cost for an extension?

Planning permission costs for extensions can vary. Use our Free Online Cost Calculator for an instant estimate on architectural design and planning permission. Council application fees in England range from £206 to £462. Be prepared for potential costs associated with plan amendments or resubmissions, as well as delays during the planning process.

Do you need help or advice on planning permission for your extension?

Need help or advice on obtaining planning permission for your extension? Resources like the Planning Portal or your local council website may provide some information, although it can be confusing and seem contradictory in some cases. Consulting with a professional town planner who is familiar with local and national regulations can provide you more clarity for your extension. Contact Us for a free no-obligation consultation.


To summarise, planning permission is a crucial step when it comes to building extensions. It ensures that your project is in compliance with local regulations and safeguards the interests of your neighbours and the community. While there are some cases where you can build an extension without planning permission, it’s important to seek professional guidance to determine if your project falls within the permitted development rights. Engaging an architect and a town planner can greatly assist you throughout the planning permission process and ensure a smooth and efficient application. Remember, obtaining planning permission may take time, so it’s essential to plan ahead and be patient. Failure to obtain the necessary planning permission can result in penalties and even demolition of the structure, so it’s better to be safe than sorry. If you need any help or advice regarding planning permission for your extension, don’t hesitate to reach out to our team of experts who are here to assist you every step of the way.

Return to Blog