Permitted development vs planning permission: what’s the difference?
Founder, Planning to Build
Photo by Joylynn Goh on Unsplash
If you’re planning changes to your home, one of the first questions you’ll face is whether you need planning permission - or whether your project might be covered by permitted development. Both form part of the same planning system, but they apply in different situations and involve very different processes. While permitted development allows certain types of work to go ahead automatically within set limits, planning permission requires a formal application and approval from the local council.
Understanding the difference early can make a significant difference to how smoothly your project progresses. It can help you avoid unnecessary applications, reduce delays and costs, and give you confidence about which route is right before you commit to designs, builders, or professional drawings.
Permitted development vs planning permission
When homeowners talk about “needing planning permission”, they’re usually referring to two different systems: permitted development rights and the planning permission application process. Understanding the difference can save you months of time and thousands of pounds.
Permitted development: pre-approved rights
Permitted Development is a set of national rules that allow certain types of building work without applying for planning permission.
If your project fits within these rules, you can usually go ahead without submitting a planning application to the council.
Typical examples include modest rear extensions, some side extensions, loft conversions and outbuildings like garden rooms or home offices.
The key thing to understand is permitted development isn’t “no rules” - it’s pre-approved rules.
You still have to meet strict limits on things like size and height, distance from boundaries, materials and appearance and impact on neighbours. If you stay within those limits, you don’t need to apply for planning permission.
Planning permission: case-by-case approval
Planning permission is required when your proposal falls outside permitted development.
This means submitting an application to your local council, which they assess based on local planning policies, impact on neighbours, design and appearance, and whether the property is affected by restrictions such as conservation areas or Green Belt designation.
In most cases, local councils aim to reach a decision on a planning application within eight weeks of validation, and for larger or more complex proposals the statutory time limit is 13 weeks.— Planning Portal Guidance
Applying for planning permission usually takes 8–13 weeks, involves higher upfront costs for fees and drawings, and comes with some risk, as there’s no guarantee the proposal will be approved.
That said, planning permission can allow larger extensions, greater flexibility in design, and types of development that aren’t permitted under permitted development rules.
The key differences at a glance
At a high level, permitted development and planning permission differ in how decisions are made, how long the process takes and how much flexibility you have. The table below summarises the key differences most homeowners need to understand.
Permitted development allows certain types of work to go ahead without submitting a formal planning application, as long as national rules are met. | Planning permission requires a formal application to the local council, which they assess before any work can begin. |
|---|---|
The rules for permitted development are set nationally, so they are broadly the same across England. | Planning permission decisions are made using local planning policies, which can vary between councils. |
Because no application is needed, permitted development is usually faster and cheaper to proceed with. | Applying for planning permission is slower and more expensive, due to fees, drawings and consultation periods. |
Permitted development works within strict limits on size, height and design, which must be followed exactly. | Planning permission allows greater flexibility in size and design, subject to council approval. |
If all permitted development rules are met, there is less risk of refusal, as the development is already allowed in principle. | Planning permission is not guaranteed, and proposals can be refused even after time and money have been spent. |
When permitted development is usually better
Permitted development is often the better option when the proposed work is relatively modest and fits within established national limits. Homeowners tend to favour this route when speed, cost certainty and simplicity matter, as there is no formal planning application and far less risk of refusal.
For common projects like smaller rear extensions, loft conversions or garden buildings, permitted development can allow work to move forward quickly, provided the rules are met.
When planning permission is the right route
Planning permission is usually the right approach when a project is larger, more complex, or doesn’t fit within permitted development limits. It may also be necessary where permitted development rights don’t apply at all, such as in certain locations or for particular types of property.
While the process takes longer and approval isn’t guaranteed, planning permission can offer greater flexibility over size, layout and design, making it the better option for more ambitious proposals.
Confirming permitted development with the council
Permitted development rules can be quite detailed, and in some cases it isn’t immediately clear whether a project falls within them or whether planning permission is required. In these situations, homeowners may choose to apply for a Lawful Development Certificate so the council can formally confirm how the rules apply to their proposal.
The council’s role is to assess the proposal against permitted development rules, rather than judge its design or impact. If the rules are met, the council issues a certificate confirming the work is lawful, providing written proof that planning permission was not required.
In most cases, a Lawful Development Certificate is not legally required for work carried out under permitted development. If your project genuinely meets the rules, you can usually proceed without applying for one.
However, because the rules can be complex and open to interpretation, many homeowners choose to apply for a certificate for clarity and reassurance, even though it isn’t mandatory - particularly where the limits are close, the property has been altered before, or future saleability matters.
Once you understand the difference between permitted development and planning permission, the next step is to confirm which route applies to your own home. Many homeowners choose to check this before committing to designs or builders, to avoid delays or unexpected costs later.
From here, you may want to explore a more detailed permitted development guide or use a checker to see how the rules apply to your specific property.