How Big Can My House Extension Be? - Pride Road Architects

How Big Can My House Extension Be?

27/02/2020, by Lisa Raynes, in Main Blog

One thing we get asked is ‘how big can my house extension be?’ or ‘how much can I extend my house without planning permission?’ There is some good news! In May 2019, Pride Road shared an article which reported that the temporary rules allowing bigger single-storey rear extensions without a full planning application were being made permanent.

The permitted development rules now allow you to build an extension without planning permission of up to eight metres if your house is detached – attached properties (semi or terraced) can have a single-storey extension of up to 6 metres, while detached properties can have a single-storey extension of up to 8 metres without planning permission.

But, are there circumstances where you will need permission, even if you’re within this size? Yes! So, if you want a bigger kitchen, an extra bedroom or a utility room – here’s what you need to know:

If you’d like to make any major modifications to your property, it’s likely you’ll need planning permission. This includes changing the use of your home (e.g. to commercial property), or building a new structure.

Starting the work without checking and getting permission first can result in you having to undo everything that’s been done. This will be a huge loss of money, plus extra to undo everything. Therefore, it’s essential you’re 100% clear before proceeding.

Your Permitted Development Rights

Extensions are considered a permitted development if they meet certain criteria, meaning you can perform a certain amount of work on a property without the need for planning permission. These rights come from general planning permission granted by parliament as opposed to your local authority.

While the permitted development rights rules have been relaxed, you do still need to ensure your property isn’t a listed building, isn’t situated in a conservation area and hasn’t already used up its existing permitted development rights.

The extension must not cover any more than half of the original garden (which includes any outbuildings) and must not contravene the ‘right to light’ regulations – which protects the amount of natural light your neighbours receive. As with all extensions, you will also need to share your plans with those neighbours for their approval.

Some other criteria to consider include:

  • If it’s not higher than the highest part of the roof
  • The materials are similar in appearance to the existing house
  • It doesn’t include a veranda or balconies
  • It’s no more than half the area of land
  • Any upper-storey windows are obscure glazed

However, rules can differ based on the type of property, such as flats. Also, as mentioned, there are restrictions if you live in a conservation area, for listed buildings, or for areas of outstanding natural beauty.

If you’re unsure, it’s always best to check with your architect and Local Planning Authority. Don’t simply assume – as the consequences can be huge!

Important: Even if an extension is permitted development, we would still advise you to get a certificate of lawful development. This is needed when you come to sell the house or need to remortgage. We would advise you to wait until you have it before you proceed with the project.

What else do I need to know about my planning permission?

Very often, people don’t realise that conservatories, as well as extensions, can require planning permission. Of course, if your plans fall within permitted development rights it is more likely to be approved, but this will depend on its size.

In all planning application cases you may be asked to submit additional reports and if you live in a conservation area, listed development or recent development you may find your permitted development rights have been revoked.

At Pride Road, one of the things our architects do is ensure our clients are completely comfortable with the planning process. This may be as simple as talking you through permitted development rights or helping with every stage of a full application. We can risk assess things for you, let you know what things might come up, advise on materials, register the application and help you respond if it’s rejected. So don’t worry, you’re in safe hands.

Still not sure?

Simply book an appointment with us, and our architect will come to your house for an initial consultation. We will carefully listen to your household needs and ideas and discuss your budget so that you aware of all required permissions, current regulations and a time frame involved.

Read more:
Do I need planning permission for my extension?
Common mistakes to avoid when extending your home