When Can a Loft Conversion Be a Permitted Development?

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

Permitted Development Basics  

A loft conversion 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 loft conversion 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 loft conversion and restore the property back to its original state. 

When Can A Loft Conversion Be Permitted Development? 

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

• The loft extension must not increase the space by more than 40 cubic meters for terraced houses, or 50 cubic meters for detached or semi-detached houses.  
• Roof extensions, apart from hip to gable extensions, must be set back at least 20 centimetres from the original eaves. 
• The new roof must not be higher than the existing roofline. 
• The conversion cannot extend forward, past the front of the house, or make significant changes to the roof facing the road.   
• Windows on the side must be made of obscure frosted glass, and they must either be non-opening or only open at least 1.7 meters above the floor. 
• The materials used for the extension must look similar to those used in the existing house. 

However, even if your loft conversion 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 loft conversion 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 converting or extending your loft space and would like any help or advice contact us for a free no-obligation consultation.