What size extension can I build without planning permission? This article looks at if you can build an extension without planning permission in the UK.

Do I Need Planning Permission to Build an Extension?

Yes, in a nutshell, although there are certain limitations. Although adding a new structure to your property can first seem like a great idea, if you understand the regulations, you'll realise how difficult it can be to gain planning permissions. 

However, given that permitted development rights were increased in 2013 under the Larger Home Extension Scheme, it should not be surprising that demand for single-storey extensions and conservatories in conservation areas has significantly increased among architects, builders, and double-glazing companies across England.

Due to this, we determined that now would be the best moment to specify the precise scale of a structure that can be erected without receiving planning clearance, especially in conservation zones.

It may be quite thrilling and sometimes a little intimidating to plan a home extension. There are various factors to take into account, from selecting the best experts for the project to selecting the ideal design and spending plan. Making sure that all expansion requirements are followed and that planning permission is requested when legally necessary are two issues that are on many people's minds.

In addition, a house could be regarded as an authorised development, which exempts it from the need to file a planning application. The biggest advantage of doing this is that you can start your project considerably sooner because you won't have to wait the twelve weeks required to request planning clearance. Additionally, you might save hundreds of pounds on the application expenses.

For an extension, you would need planning approval if it was closer to the public roadway. No extension may extend higher than the roof's highest point. You would need planning clearance for the extension if it were higher than the roof.  

What Size Extension Can I Build Without Planning Permission?

Furthermore, if you do not reside in a conservation area (an AONB or national park for example), the maximum for single-storey back expansions increases to eight metres for detached dwellings and six metres for other property types, subject to prior clearance.

Of course, the essential language here is "subject to prior consent," which implies that for these larger extensions, you must tell the council of your intentions, after which the council will confer with your neighbours to highlight any objections. If there are any complaints, it will be up to your local planning authority to decide whether the expansion may go forward based on the impact on the amenity of neighbouring houses.

What Is The Maximum Extension On Homes In Conservation Areas Without Planning Permission?

Depending on the results of the Neighbour Consultation Scheme, single-story extension projects are authorised in conservation zones as long as the detached property extensions and connected property extensions do not go beyond the original home's back wall by more than 3m and 4m, respectively.

Is Your Property A House?

You cannot construct an extension without receiving full planning approval since authorised development rights do not apply to flats, maisonettes, or any other sort of construction. Be aware that your property might not have approved development rights if it has previously undergone a change of use or been transformed into a home.

Permitted development rights are legal laws that enable you to enlarge your house without obtaining planning approval as long as certain requirements are followed. If you wish to do anything more, you'll probably need to apply for household planning permission; a planning expert may be able to assist you in completing your project effectively.

Has The House Been Extended Since 1948?

If so, your permissible development limit will be reduced by these expansions. In the event that a house has already been enlarged, whether by you or the previous owners, you cannot do so without planning approval. This regulation applies to extensions granted after July 1, 1948.

Is Your Property Listed Or On 'Designated Land?'

The term "designated land" (also known as "designated landscape") refers to geographical regions that have been deemed important by statute at the international, national, or municipal level or that have been noted in development plans or other documents.

Other "protected" regions are the Norfolk or Suffolk Broads and National Parks. If your land is subject to an "Article 4" directive, your allowed development rights may even have been eliminated. Hopefully, the only restriction on your ability to construct on the designated property is that you are not able to add a side extension, a second story, or outside cladding.

Are There Any Conditions Or Limits To Extending Without Planning Permission?

Terraced & Semi-Detached Homes

Without planning permission or the cooperation of the neighbours, extensions to a terraced or semi-detached residential property are not permitted if they exceed 4 metres in height, 3 metres in length, or are two storeys high.

However, under the neighbour consultation plan, homeowners are allowed to add up to 6 metres to a terraced or semi-detached house, providing that all impacted neighbours agree in favour of the extension.

After your neighbours have had 21 days to object, the local administration must give the "all clear." When a valid development certificate is granted, which might take up to 8 weeks, you can begin your more involved expansion project.

Detached Homes

Detached dwellings are also subject to height limits, however, you are permitted to expand your home's back by up to 4 metres without the neighbours' or the local government's consent. The method for extending detached dwellings up to 8 metres is the same as for attached homes under the neighbour consultation programme.

Rural & Listed Homes

If you're fortunate enough to reside in a conservation area or an area of outstanding natural beauty, your extension must be one story and no taller than 4 metres. Stone, pebbledash, render, lumber, plastic, or tiles are not permitted to be used to clad the structure.

No matter the proposal, listed homes require Listed Building Consent. If the development lies inside the perimeter of a listed building, planning approval could be necessary. However, in rare circumstances, a building permit may already have been approved. We're here to help you with this.

Contact a skilled and qualified team of architects if you have any more queries about extending your residential home, with or without planning permission.

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Kirk-Brown Ltd are experienced in producing working drawings for building extension and conversions. These drawings are fully compliant with the related Part of the Approved Documents and can be submitted for Planning Approval and Building Control Approval.

We can additionally create specifications for the project and organise any administration required. If you have any questions regarding our services please simply get in touch to speak with our chartered surveyor.