Planning Permission vs Building Regulations — What’s the Difference?
One of the biggest areas of confusion for homeowners starting a residential project is understanding the difference between planning permission and Building Regulations.
Although the two are closely linked, they are actually completely separate parts of the design and construction process, each serving a very different purpose.
Understanding the distinction early on can help make the overall process feel much clearer and easier to navigate.
What Is Planning Permission?
Planning permission focuses on how a proposed development looks, how it impacts the surrounding area and whether it is considered acceptable from a planning perspective.
When reviewing a householder planning application, the local authority is generally considering things such as:
The size and scale of the extension
The appearance and design of the proposal
Impact on neighbouring properties
Privacy and overlooking
Relationship to the surrounding street or area
Local planning policies
Planning drawings are therefore primarily concerned with communicating the overall proposal visually.
Typical planning drawings include:
Existing and proposed floor plans
Existing and proposed elevations
Site plans
Location plans
In many cases across Worthing and West Sussex, smaller residential projects may also fall under permitted development, meaning formal planning permission may not always be required.
What Are Building Regulations?
Building Regulations are entirely separate from planning permission.
Rather than focusing on appearance and planning policy, Building Regulations deal with how a project is actually constructed and whether it complies with current technical and safety standards.
This includes areas such as:
Structural stability
Fire safety
Insulation and energy performance
Ventilation
Drainage
Accessibility
Thermal performance
Building Regulations approval is typically required before construction begins, even where planning permission may not be necessary.
What Are Building Regulations Drawings?
Building Regulations drawings are much more detailed technical drawings prepared for construction and Building Control approval.
These drawings often include:
Construction sections
Insulation specifications
Structural coordination
Drainage layouts
Technical junction details
Roof and floor build-ups
Unlike planning drawings, technical drawing packages are intended to provide builders and Building Control with the information required to construct the project correctly and compliantly.
Can Builders Work From Planning Drawings Alone?
In most cases, no.
Planning drawings are usually not detailed enough for construction purposes and generally do not contain the technical information required for Building Regulations approval.
Attempting to build directly from planning drawings alone can often lead to:
Missing information
Delays on site
Confusion during construction
Additional costs later in the process
For this reason, most residential projects move from planning drawings into a dedicated technical design stage before works begin.
Which Comes First?
Typically, the process follows this order:
Planning Approval (if required)
Construction
Although every project is different, this staged approach helps create a much clearer and more manageable process for homeowners.
You can see the FULL PROJECT JOURNEY HERE:
Do I Need Both?
Often, yes.
Many residential projects require both planning approval and Building Regulations approval before construction can begin.
However, some smaller projects may not require formal planning permission if they fall under permitted development, although Building Regulations approval is still commonly needed.
Starting a Residential Project
For many homeowners, simply understanding where planning permission ends and Building Regulations begin can make the process feel significantly less intimidating.
At Downland Studio, projects are approached collaboratively and practically, helping homeowners across Worthing and West Sussex navigate each stage clearly and confidently from initial ideas through to construction-ready drawings.
If you’re considering an extension, loft conversion or internal alteration project and would like some honest advice before getting started, feel free to get in touch for an informal conversation.