Do you need planning permission to build an extension in York?

In this article we’ll explore whether or not you need planning permisison to build an extension in York.

An extension is an excellent way to add extra space, add functionality, and increase the value of your property.

Adding a thoughtfully designed extension can provide a much-needed segregated relaxation area, such as a snug or sun room…. or, as is particularly fashionable in recent years, an open-plan kitchen-diner or kitchen-living room.

However, before you embark on your first DIY refurb project or pick up the phone to call a builder, there are planning permission considerations.

Full Planning or Permitted Development for your extension?

Extensions can fall into two categories when it comes to planning permissions – Permitted Development and Full Planning Permission.

Permitted Development rights set out national guidelines allowing certain building works without needing planning permission, subject to certain conditions being met.

Under permitted development, there are two different applications you can submit to your local council “Lawful Development: Proposed Use” and “Prior Approval: Larger Home Extension”.

In many cases, your requirements may be acheived by a permitted development extension.  A Lawful Development: Proposed Use application will provide you a Certificate of Lawfulness confirming your proposed plans meet the criteria.


Why is a Certificate of Lawfulness Important?

Should you come to remortgage or sell your property, it’s important to demonstrate that permissions for your extension have been built in line with permitted development rules.

In the event that you proceeded informally under permitted development and later down the line the legislation is withdrawn or the criteria is altered; you would have no date stamped certificate to demonstrate that it was compliant when it was erected.

Proceeding without the permitted development certificate exposes you to the risk of putting your sale on hold until it’s resolved with your local council. Something particularly problematic if there is a chain on either side of the transaction.

This scenario leaves the success of your sale in the hands of the local council’s planning officer.

Best case scenario your sale is delayed by 8 weeks (planning timescales) and the time taken for your architectural service provider to draw up the plans, then prepare and submit the retrospective application.

In contrast, Full Planning Permission is for more extensive alterations which involves consultation with the local authority and it’s consultants such as the water board, highways etc in addition to your neighbours. As with permitted development, the timescales is also quoted as 8 weeks to get across the line, but can vary depending on your local council’s workloads (all the worse for public spending cuts etc).


What’s the Permitted Development Criteria on Extensions?

For extensions to fall under permitted development, it would need to be to either the rear or side elevations.

If you would like to forwards to your principle (front) elevation, you will need to apply for full planning. This goes for something as minor as adding a bay window.

For the sake of clarity, we’ll address permitted development under a Prior Approval: Large Home Extension application in a subsequent article.


Single Storey Rear Extensions

Dimensions –

  • A terraced or semi-detached house may only extend up to 3m beyond the rear of the original wall
  • A detached house may extend up to 4m beyond the original wall
  • A maximum height of 4m and no higher than the ridge line of the existing house
  • If the extension would be within 2m of a boundary, the maximum height is 3m

Others –

  • If the building which is to be extended is located in a Conservation Areas, Areas of Outstanding Natural Beauty, National Parks and the Broads, Land within World Heritage Sites: no cladding. If you think your scheme would benefit from cladding, you would need to apply for full planning and your local planning and conservation officer would have to be in agreement.

Double Storey Rear Extensions

Dimensions –

  • No double storey side extensions
  • The eaves and ridge cannot be higher than those on the existing house’s.
  • A maximum eaves height of 3m if within 2m of a boundary and no higher than the host house.
  • The extension must be a minimum of 7m from the rear of the boundary
  • The pitch of the roof must match as closely as possible to the host dwelling

Others –

  • Windows and rooflights on the upper floor that are on the sides must be obscured and non-opening.
  • No double storey rear extensions in Conservation Areas, Areas of Outstanding Natural Beauty, National Parks and the Broads, Land within World Heritage Sites

Single Storey Side Extensions:

Dimensions –

  • The maximum height is 4m and must be no higher than the ridge of the original house
  • A maximum eaves height of 3m if within 2m of a boundary, also no higher than the existing house
  • The width of the extension cannot exceed 50% of the width of the original building.

Others –

  • No side extensions in Conservation Areas, Areas of Outstanding Natural Beauty, National Parks and the Broads, Land within World Heritage Sites

We have a great article explaining what a Conservation Area is and have compiled a user friedly table outlining all 35 of them.

What other restrictions apply to all enlargements and extensions?

Your extension and all the outbuildings which include sheds or garages can only make up a maximum of 50% of the original space around the house. So the bigger your garden the greater the flexibility…However, if your garden is substantial enough, could you build an additional house on the adjacent land? These are highly sought after by small developers?

The materials must be in line with the existing house and surrounding context. So if you would like a modern extension which proposes new material such as zink or timber cladding, then you’ll need to apply for full householder planning approval.

Lastly, no verandas. No balconies. No raised platforms (above 30cm).


Where does Extensions (Class A) Permitted Development Not Apply

  • Where the enlarged part of the dwellinghouse would extend beyond a wall which fronts a highway and forms a side elevation of the original dwellinghouse; (think corner plots)
  • Flats and maisonettes
  • Houses which have come into existence as a result of permitted development rights. If you’re not sure, check the planning public access. (One exception, however, are houses arising under the old Class O permitted development for office to dwellinghouse
  • Listed Buildings (that goes for any type of permitted development)

*** According to technical guide from the Ministry of Housing, Communities & Local Government, the definition of a highway is:

“public right of way such as a public road, public footpath and bridleway. For the purposes of the Order it also includes unadopted streets or private ways.

Therefore, the term ‘highway’ covers all rights of way, from a motorway to a public footpath.

Diagram illustrating extensions on corrner plots not being permitted development.
Source: Ministry of Housing, Communities and Local Government – Permitted development rights for householders -Technical Guidance

What’s an Article 4 Direction?

Some councils can impose an article 4 direction, which can remove permitted development rights. This is done to ensure that they have more say on what is built and it is a useful tool to ensure that any developments preserve the character of the local area.


I don’t think I achieve what I need with Permitted Development… what else should I bear in mind?

Another consideration is your local council may have additional guidelines which a planning officer will reference in determining your Full Planning application. In the case of York, for extensions there is the Supplementary Planning Document (SPD) draft House Extensions and Alterations (2012). But there are many others such and have a bearing on your plan. Click here for a comprehensive list of planning policy documents for The City of York.

Lastly, there are occasions where a new build has had it’s permitted development rights removed. Check your council’s planning access for the approval document and the associated conditions. It may look something like this:

“Notwithstanding the provisions of Article 3 of the Town and Country Planning (General Permitted Development) Order 2015 (or any Order revoking or re-enacting that Order), development of the type described in Classes A and B of Schedule 2 Part 1 of that Order shall not be erected or constructed.”

Which is a wordy way of saying you’re not allowed an extension or a dormer unless you apply and are granted full planning permission.


I’m not 100% sure if my extension falls under permitted development?

We appreciate there are many factors at play. If you have a clear vision of what you require, then it’s possible to ask your local council whether or not your project would fall under permitted development.

The City of York Council provides a “Householder enquiry form” to answer this type of query. This consultation service is available to the public or a small fee of £99.

In many circumstances, permitted development is too and you might not acheive what you need. In which case it’s worth exploring other avenues. An architect can be invaluable towards providing insight and new ideas to get you where you want to be.

Will my extension require building control approval?

All extensions regardless of size require building control approval.

We recommend preparing a Full Plans application for submission to building control.

We can prepare the plans, elevations, specification, detailed sections and co-ordinate these with your appointed structural engineer

Did you know we won an award for the quality of our work on this subject? Click here for more information.


Got it? Let’s get started.

Making sure your extension is compliant with planning rules is essential.

We have extensive knowledge of local planning policies and a proven track record guiding clients through the planning and building regs process.

We are happy to provide consultations and guidance specific to your property, giving you the best holistic overview what’s achievable with your requirements and the best strategy to achieve it.

Book your hassle free consultation today!

If you’re really nerdy like us or merely want to learn more about household permitted development, click here to read the official government guidance.