What is Permitted Development and how can I use it for my extension project?
Not all structural changes made to your home require planning permission. Depending on the scale of the project, it may fall under something called Permitted Development. But if you haven’t come across Permitted Development you may not be aware of the criteria and how it works. Below we cover the basics so you can decide how you can use it for your extension project.
What are permitted development rights?
Permitted Development rights is a government scheme that lays out a set of criteria of structural changes that can be made without the need to apply for full planning permission.
Different types of permitted development are available depending on the property type, which apply to most houses but not maisonettes and flats, where planning permission has to be sought.
What does permitted development allow you to do?
While the boundaries of Permitted Development changes depending on the work you propose to carry out, there are specific projects you can complete without asking for planning permission. Below are some of the basic criteria required:
Side extensions
It can only take up 50% of the surrounding land and be less than 4m in height, with eaves and a ridge that does not stand taller than the current property. It must also be no wider than half the width of your existing house. Materials similar to those featured on the existing house must also be used.
Rear extensions
An attached house cannot extend beyond the rear wall of the current property by 6m, for detached homes this is 8m. It must use similar materials and be no more than 50% of the land/garden. The eaves and ridge rule is the same as a side extension and it cannot be higher than 4m. This changes to 3m if positioned within 2m of the property boundary.
Two-storey extension
The side elevation cannot have windows in the roof slope or wall and the extension must be no wider than half the width of your existing house. The extension must have eaves and a ridge no taller than the existing property, and a new terrace cannot be any more than 3.5m higher than the next tallest terrace.
Wraparound extension
When a rear and side extension are combined for a wraparound design, criteria for both extensions are used when judging whether or not it can be built within Permitted Development guidelines. However, given the large amount of space required it is unlikely to fall within the allowed boundaries.
Loft conversion
Detached and semi-detached houses can add a maximum of 50 cubic metres additional roof space, while windows cannot be included in any roof slope or wall that forms a side elevation. The roof pitch must remain the same as the existing property and it must feature a dormer wall that sits at least 20cm from the current wall face.
Garage conversion
For this project, you must ensure that the building size is not enlarged and that all works remain internal. However, if a detached garage is being converted into a living space such as a living room or bedroom, planning permission may be needed.
What are the restrictions of Permitted Development rights?
If you live in a flat or maisonette you will not be able to build an extension using Permitted Development rights. Your ability to use them may also be affected if you live in a listed property.
Designated Areas, such as an Area of Outstanding Natural Beauty or a National Park or Conservation Area have restrictions in place that could limit your freedom to use Permitted Development rights.
Self-build projects also have some limitations in place if you are planning to construct a new house that is bigger than the existing one.
Before you start work on any new project you should always check with your local authority. If you are working with an architect they can carry out the required checks on your behalf.
Recent changes to permitted development
Since August 2020 there have been a number of changes to Permitted Development rights. Mercantile to Abode (MA use class) enables you to turn commercial premises into residential spaces without planning permission. Two-storey extensions are now also easier to build, with a fast-track process making the application process much more straightforward.
How to check your Permitted Development rights
If you are planning an extension project in Cambridge and are unsure if your project meets Permitted Development criteria, we are able to help. Book a free consultation and we’ll discuss the project in more detail to see what can be built without requesting planning permission. Call us today on 07984 760 920 or send us a message here and we’ll get right back to you.
