Permitted Development vs Planning Permission
Learn MoreSuccessfully navigating the planning system isn’t easy.
This is partly due to the huge number of planning policy documents and guidance notes available online, but also because some local policies can be quite generic, so applying them to your specific circumstances can be challenging.
That’s why we have created a simple step-by-step guide, explaining how the planning system works in practice and how to make sure you get planning permission.

1. What is planning permission?
Planning permission involves asking your local planning authority if you can carry out specific building works. Ideally, you should first discuss your ideas with an architect or planning consultant. Once they have prepared all the relevant plans, they can submit them to the local authority (council) for them to be assessed by a planning officer.
The planning department’s decision will then either be:
- Approval (subject to condition)
- Refusal
The planning policies referred to by your local authority to assess your application will vary according to where you live, but will certainly include the National Planning Policy Framework (NPPF). This is a high-level policy document that usually focuses on strategic topics. Below the national level, there may also be a regional document. For example, in London, this would be The London Plan.
At a more local level when it comes to householder extensions, your local authority will have a host of different policy documents, the most relevant of which will be their local plan. The documents which make up the local plan will vary from borough to borough but usually the most important will be a core strategy setting out the borough’s vision for the future. The local authority may also refer to a development management policy document, which would typically be useful for property developers working on larger projects.
The most important document for everyday homeowners would be the ‘Residential Design Guidance’, which is a document setting out what kind of designs and sizes specific types of extensions can comprise. For example, it might say that terraced houses can have a single-storey rear extension of 3m deep while semi-detached and detached houses could build slightly deeper. If your local authority has this document, it’s always a very useful place to start when thinking about your ideas as it will set out very clear parameters of what is acceptable or unacceptable. By having a clear understanding of your local authority’s design guidance you will be in a better position to understand how to get planning permission.
2. What are the penalties if you don’t get planning permission?
A failure to obtain planning permission is usually referred to as a ‘planning breach’.
Usually, there would be two reasons for a planning breach.
- Planning permission was never granted (whether it was refused or never applied for)
- A proposed development that has been built fails to adhere to the planning conditions on the decision notice.
That being said, a breach of planning permission is not in itself illegal. If your local authority becomes aware of any particular breach, they will usually pass the case over to an enforcement team who should suggest that one applies for retrospective planning permission to retain what has been built. If your retrospective planning application were to be refused or you built extensions that had previously been refused, the local authority could well issue you with an enforcement notice.
This will make clear what planning breach has occurred and what action needs to be taken to remedy the situation. In most cases, they would ask for the offending extension to be removed in its entirety. It should be noted that it is against the law to disregard an enforcement notice. If one fails to comply with a notice, the council can take legal action through the courts.
3. When do you need planning permission?
There are three main scenarios where you would need planning permission:
- When you want to create a new building
- When you want to extend your current building
- Where you want to change the use of your building.
When it comes to extending houses, certain changes can be made through the use of ‘permitted development’ that do not require planning permission. Before carrying out any works, we would always advise that you first speak to a planning consultant. If you’d like to speak with one of our team, you can call us anytime as we’re experts in how to get planning permission.
4. Outline of the process
The planning permission process can be divided into two separate stages: design and planning.
4.1. Design
- Architect’s survey: A surveyor will take the dimensions of both the inside and outside of your property.
- Existing Drawings: Your architect will take the survey measurements and create a full set of existing plans, sections and elevations to the exact scale of your house.
- Design Meeting: This is the most exciting part, where your ideas come to life. You will have a meeting with your architect and discuss what you are looking to create.
- Preliminary Drawings: This is where an architect’s creativity begins to shine; they take all the ideas gathered from the design meeting and create a full set of floor plans and elevations.
- Revisions: Now you have the opportunity to view your dream home for the first time by looking over the first set of draft plans. As always, there may be small things you might want to change.
- Final Issue: Once all the revisions have been made the full set of drawings will be sent to you for final approval. Your plans can then be submitted.
4.2. Planning Stage
- Submission: Your architect or planning consultant will complete all the relevant forms and submit your application
- Planning Fee: You will receive a payment link from the Planning Portal
- Application received by local authority: Once the fee has been paid, your local authority will download the application from the planning portal
- Validation: The council’s validation team will make sure all the plans are correctly labelled and all relevant forms are completed accurately
- Planning Officer Assigned: Your local authority will assign your application to a planning officer
- Neighbour consultation: Your neighbours will be consulted and given 21 days to make any comments on your application
- Application Review: The local authority planning officer will assess the proposed plans based upon character of the area, design and impact on your neighbours etc.
- Decision: A decision will be issued 8 weeks after the application was validated.
5. What will you need to do when applying for planning permission?
Once your architect has prepared all the relevant drawings, they will submit them on your behalf. The process is relatively straightforward. All the relevant forms can be completed online which involves answering a host of questions about your property and proposal, such as your circumstances, the plot size, whether you’re the sole owner of the property etc.
Once all the forms have been submitted, the following section is where one uploads all the relevant plans. You can then select various options, which will generate the fee to pay. Your consultant will then submit the application online and your local authority will then download the entire submission once payment of their fee has been received.
6. Who can help with planning permission?
6.1. Architect
When it comes to householder extensions, people’s first port of call is usually an architect. When choosing an architect it always helps if they have experience of working in your location as they will understand all the relevant local policies.
6.2. Planning Consultant
The person who assesses your plans once they have been submitted is not an architect but a planning consultant. Local authorities employ teams of planning officers whose job is to understand all the relevant policies and assess your submitted plans. Strangely enough, most architectural degrees focus mainly on design with very little time devoted to local planning policies which one needs in order to get planning permission.
That’s what makes Adara a little different from other architectural practices. Many members of our team previously worked as planning officers for several local authorities so have a very good understanding of how the process works in practice. When this prior knowledge is combined with the creativity of our in-house architects, we have a very high success rate.
7. How much does it cost to get planning permission?
Below are the fees for a single storey 3m deep rear extension and loft conversion to a semi-detached house.
Architects’ fees for planning: Approx. £1,200- £1,600
Local authority fees: £100 – £250
Note that fees may vary according to the specifics of the project being submitted.
8. Who decides and what are the criteria?
Once the application has been submitted, the assigned planning officer will assess your plans against several categories:
- How will your plans affect the character of the area?
- How will your plans affect the living conditions of neighbours?
- How will your plans affect your living conditions?
- Will any trees be affected?
9. Will there be any impact on the public highway?
Hopefully, the architect and planning consultant who prepared your plans will have already thought about all the above questions before the designs were finalized, meaning you won’t have any problems at all.
10. What should I focus on to make sure I get planning permission?
Architect: Always instruct an architect who has a good understanding of local planning policies and has previously worked in the area in which you live.
Planning consultant: If your ideas are relatively straightforward and not controversial, you may not need a planning consultant. But for more complicated projects they can be very useful as they will have a good understanding of all the relevant planning policies and how the planning process works in practice.
Extension size: It’s always a good idea to have a walk up and down your road to see the types of extensions some of your neighbours have built. You can even use Google 3D which is a very useful tool as you can actually measure the various dimensions of neighbouring extensions.
Planning history: It can also be very useful to examine your local authority’s planning register where you will be able to search for previous applications made on your street. The case officer’s delegated reports within those applications will provide very helpful information regarding how your local council will assess your particular extension. This information should be available online via the planning portal.
Communication with the planning officer: We always think it’s a very good idea for your architect to introduce themselves to the planning officers once your application has been submitted. This enables them to make it clear that should any minor changes be required, you will be more than happy to make them. This can potentially avoid your application being refused.
11. How long does it take to get planning permission?
Validation: usually it will take your local authority approximately 1 – 2 weeks to validate your planning application or lawful development certificate after submission.
Householder applications: these applications are usually determined within 8 weeks of validation.
Larger schemes: major planning applications can sometimes take up to 13 weeks to be determined.

What happens once planning permission is approved?
After celebrating, you will then move onto the building control stage:
Detailed Drawings
Your architect will prepare a set of detailed drawings showing features like foundations, steelwork, insulation etc. Essentially this will be a set of plans to make sure your extension meets all the relevant British Standards.
Your architect will prepare a set of detailed drawings showing features like foundations, steelwork, insulation etc. Essentially this will be a set of plans to make sure your extension meets all the relevant British Standards.
Engineer
Once the detailed plans have been prepared, they can be sent to an engineer who will produce a set of structural drawings/calculations, ensuring that all the steel and foundation meet the relevant British Standards.
Submission to building control
Once you have a detailed set of architectural drawings and a full set of structural calculations/drawings, you can submit your application to the local authority building control department. You can either use an approved inspector to do this on your behalf or go direct to your local authority.
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