Planning a home extension is exciting, but before construction begins there is an important question to answer: do you need planning permission?
The answer is not always yes.
Certain home extensions can potentially be constructed using permitted development rights, while others require a formal planning application.
The important thing is to establish which rules apply to your particular property and proposed design before committing to the build.
What Is Permitted Development?
Permitted development rights allow certain types of improvement to be carried out without making a conventional planning application, provided the project meets the relevant requirements.
This can make straightforward home improvements considerably easier.
However, permitted development is not a blanket permission to build anything you choose.
Restrictions can apply to matters such as the dimensions, position and design of an extension.
Individual properties may also have different rights.
When Might Planning Permission Be Required?
A planning application may be necessary where the proposed extension falls outside permitted development limits.
This could relate to its:
- Size
- Height
- Position
- Proximity to boundaries
- Relationship with the existing property
- Design
- Location
Properties in conservation areas and certain other designated locations may also face additional restrictions.
Listed buildings require particularly careful consideration.
Don’t Assume Your Neighbour’s Extension Sets a Precedent
It is easy to look along the road, see a similar extension and assume the same project can automatically be built on your home.
That can be risky.
Your neighbour may have obtained planning permission, their property may have different permitted development rights, or the work may have been completed under regulations applying at a different time.
Every project should therefore be assessed individually.
Planning Permission and Building Regulations Are Different
This is one of the most common sources of confusion.
Planning permission broadly concerns whether the proposed development is acceptable from a planning perspective.
Building Regulations deal with how the project is constructed.
An extension may therefore not require a traditional planning application but still need to comply with Building Regulations.
These can cover issues including:
- Structural safety
- Insulation
- Fire safety
- Ventilation
- Drainage
- Electrical work
- Energy performance
Biggin Renovations’ extension services include structural construction and the associated work required to turn an approved design into a completed living space.
Why Planning Should Come Before Building
Trying to resolve permissions after work has started can cause major problems.
A proper pre-construction process helps ensure the design is viable, compliant and buildable before substantial money is committed.
It also gives the structural and construction teams a clear set of plans to work from.
Think About the Design at the Same Time
Planning should not simply be treated as a bureaucratic obstacle.
The early design stage is the opportunity to decide how your extension will improve the house.
Consider:
- Where natural light will enter
- How rooms will connect
- Whether walls need removing
- How the new space connects with the garden
- Where furniture will go
- Whether the existing kitchen needs relocating
- Storage
- Heating
- Electrical requirements
A successful extension should solve practical problems rather than merely add floor space.
Structural Considerations
If the new extension requires a large opening to be formed between the existing house and the new space, structural engineering becomes particularly important.
Biggin Renovations undertakes structural steelwork for projects ranging from individual RSJs through to substantial steel-framed extensions.
Planning the structural element early allows the architectural ambition and practical construction requirements to work together.
What About Garage Conversions?
Garage conversions often involve a different set of considerations from completely new extensions.
Some can be relatively straightforward, while others involve planning restrictions, significant structural alterations or changes to windows, doors, insulation and access.
The company’s property conversion services can form part of a broader home improvement project.
Could Permission Affect Your Timescale?
Yes.
If a formal planning application is required, the approval process needs to be built into the overall project timetable.
This is another reason to begin the planning stage well before your ideal construction start date.
Rushing the design simply to start building sooner can create unnecessary problems later.
A Better Approach to Extensions
The best extension projects bring the design, permissions, engineering and construction process together.
Rather than viewing them as separate tasks, consider the entire journey from the outset.
Biggin Renovations Group works across South London, Surrey and Kent, helping homeowners transform existing properties through extensions, renovations, conversions and structural alterations.
To discuss your plans, call 07507 476 504 for a free no-obligation consultation.
Frequently Asked Questions
Does every home extension need planning permission?
No. Some extensions may fall within permitted development rights, although the applicable requirements must be checked for the individual property.
What is the difference between planning and Building Regulations?
Planning relates primarily to whether development is acceptable. Building Regulations govern construction standards including structure, insulation and safety.
Can I build the same extension as my neighbour?
Not necessarily. The planning history and permitted development rights of two neighbouring properties may differ.
Do internal alterations need planning permission?
Many internal alterations do not require ordinary planning permission, although structural changes and work to listed buildings can be subject to other controls.
When should I investigate planning requirements?
As early as possible, ideally during the initial design stage and before construction dates are committed.
