Do You Need Planning Permission for a House Extension?

Do you need planning permission for a house extension? In this guide we will go through the questions you need to ask in order to find out.

Extending your house can seem like a complex prospect, especially if you’ve never built anything before. To know what you’re getting into, you’ll need to understand the planning permission rules and whether they apply to you.

In this article we've outlined some simple questions you can ask to determine whether your house extension needs planning permission or whether it can be built on what's called permitted development. 

Photo Credit @Outsite Co

House extension without planning permission

Does my house have permitted development rights?

The first question to ask is whether your house has permitted development rights in the first place.

If your house does not have permitted development rights, then you will need to apply for planning permission. 

Most Victorian, suburban, terraced and detached houses in the UK have permitted development rights. common examples of houses which do not have these rights include:

- Houses which have had large works before.
- Houses with article 4 actions against them.
- New build dense housing and apartments.


Photo Credit @Kai Bossom

Suburban UK House Permitted Development

Do I need planning permission for a 3 meter extension?

If you have permitted development rights, you can build a 3 meter house extension without the need for planning permission in most cases. 

Typically the maximum size of a house extension with no planning permission will be 3 metres in depth, 4 metres in height and the width of your house.

If you are in doubt, you should always check the permitted development rules and how they relate to your property.

Photo Credit @Louis Reed

3 meter extension permitted development

Can I build a house extension to a listed building without planning permission? 

The short answer is you will need planning permission and listed building consent if you house is a listed building.

Building a house extension on a listed building can be complex and depends on a building by building basis. If you'd like more information on whether your listed building house extension is possible, we offer free consultations to answer your questions.

Image Credit @Cat Miller

Listed Building House Extension

Can I build a house extension in a conservation area without planning permission?

For most conservation areas, you can build a house extension without planning permission as long as it follows the rules on size.

Additionally, your extension needs to follow the rules the conservation area outlines for appearance and materials. It is recommended to confirm with your council that permitted development will be allowed and which rules you should follow.  

Image Credit @Kai Bossom 

Conservation area house extension

My house is in the green belt, can I build a house extension without planning permission?

Houses in the green belt will always need planning permission for any alterations or extensions. 

Furthermore, the size of these house extensions must not rise above a certain threshold as outlined by your local council. 

Each council provides different thresholds if you'd like to find out more we provide short meetings to check whether your project is feasible.

Image Credit @Magda V 

Green belt House extension

My house extension does not need planning permission, what else should I know?

If your house extension is acceptable under permitted development and does not need planning permission, be aware that there are still things you will need. 

We recommend - even when your house extension does not need planning permission - that you apply for prior approval or a certificate of lawful development.

All building work requires building regulations compliance, meaning you need a local or approved building inspector.

House extensions also require structural work, meaning you will need a structural engineer. 

If you are in doubt, a good architect can manage this process and everything else in order to make sure everything runs smoothly and on budget.

Image Credit @Sven Brandsma

Black Kitchen House Extension

I've built my house extension and now I need planning permission, what should I do?

Sometimes you may find you've built a house extension and only know you need planning permission afterwards. 

This may mean your local council issue an enforcement notice or demand you formally apply for planning permission. 

In these cases, it's important to get your planning application right to avoid having to demolish your hard work.

We are experts in dealing with retrospective planning applications and enforcement notices and can offer advice on how to give your application the best chances possible.

Image Credit @Jason Briscoe

Light filled house extension


Find out if your house extension needs planning permission

Our expertise in planning policy can help you secure your house extension permission

Book a Free Consultation

Tel: +44 20 8638 5243
Email: info@seanpaynearchdesign.com

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