When Can an Outbuilding Be a Permitted Development?

In this blog, we’ll explain when an outbuilding could be considered permitted development and when planning permission may be required.

Permitted Development Basics  

An outbuilding can often be considered permitted development meaning planning permission is not required. However, there are some important caveats, to be aware of to avoid falling foul of the most common permitted development mistakes. Only houses have permitted development rights but not all houses have permitted development rights. Flats, maisonettes, and commercial properties always need planning permission. 

Planning Constraints  

Planning constraints such as conservation areas, listed buildings, world heritage sites, areas of outstanding natural beauty, article 4 directions or even living under a flight path may limit or remove your permitted development rights. Any previous developments even by a previous owner a long time ago may have used some, or all of your Permitted Development rights, meaning planning permission IS required. 

Planning policies are also ever-changing. Even if your outbuilding is permitted development today, the council can impose new planning constraints that remove your permitted development rights at any time in the future. This could result in a breach of planning, and risk enforcement action. If an enforcement notice is issued and retrospective planning permission is refused you would need to demolish the outbuilding and restore the property back to its original state. 

When Can An Outbuilding Be Permitted Development? 

If your house has permitted development rights and there are no hidden constraints that removed your PD rights, your outbuilding may not need planning permission if it meets ALL of the following:   

• The outbuilding must be single storey only.
• If it is built within two metres of a boundary, its maximum height must not exceed 2.5 metres. If it is built more than two metres from a boundary, the maximum height is 3 metres for a flat roof or 4 metres for a dual-pitched roof. In all cases, the eaves height must not exceed 2.5 metres.
• The outbuilding cannot be located in front of the principal elevation of the house (i.e., it must not be built in front of the main front wall of your house) and must be situated within the curtilage of the original house as it existed on 1st July 1948 (or when it was first built, if later).
• No more than 50% of the total area of land surrounding the original house may be covered by buildings, including any existing extensions, sheds, or other structures.
• The use of the outbuilding must be incidental to the enjoyment of the main dwelling. This includes uses such as a home office, gym, studio, or storage. It must not be used as a separate residential unit or for sleeping accommodation.

However, even if your outbuilding meets these criteria, you may still need planning permission. 

For example, if there are hidden planning constraints or your permitted development rights have been used up by previous developments. 

It is important to note that 20% of our planning applications are retrospective and 99% of these were sure they didn’t need planning permission but got it wrong. 

 With this in mind, it’s best to check with your local planning authority or a chartered town planner before commencing work to limit your risk and expense. 

How to Find Out If You Need Planning Permission?

To find out if you need planning permission you have 2 options. 

The first option is to submit a pre-application to your council.  

This requires architectural drawings showing the property before and after the works, along with a detailed proposal explaining your plans and how they meet the relevant planning policies.  A pre-app costs up to £600 and typically takes 5 to 8 weeks for a response, though it’s not a legal determination and doesn’t guarantee approval. 
 
Alternatively, our town planners can provide a planning appraisal.   

We check the same planning policies, planning history, and planning constraints as the council but without the need for architectural drawings or a detailed proposal. The advantage of a planning appraisal is you’ll get the answers you need within a day instead of waiting weeks. 

A Lawful Development Certificate  

For anything likely to be considered Permitted Development it is always recommended to obtain a Lawful Development Certificate before commencing any works. A Lawful Development Certificate is the only way to prove that your development is Permitted Development and does not need planning permission.

It is also often required when selling or remortgaging your property, to prove to buyers or lenders that all modifications are lawful. Without planning permission or a lawful development certificate your outbuilding may not increase the value of your property. By securing a Lawful Development Certificate, you’re investing in both the future security and potential value of your property.

If you’re considering installing an outbuilding and would like any help or advice contact us for a free no-obligation consultation.