If you’re planning a home extension, loft conversion or major renovation in the UK, two approvals usually come up early in the process: planning permission and building regulations.
Although they’re often mentioned together, they serve very different purposes. Confusing them is one of the most common reasons residential projects are delayed, redesigned, or end up costing far more than expected.
In simple terms:
- Planning permission controls what you are allowed to build and how it affects its surroundings.
- Building regulations control how the work must be carried out, ensuring safety, performance and legal compliance.
Understanding the difference before committing to a design or speaking to a builder can save you time, stress and money.
What Is Planning Permission?
Planning permission is concerned with the impact of development on its context. It is assessed by your local planning authority and focuses on how a proposal fits within its surroundings.
Typical considerations include:
- Appearance and scale – size, height, massing and materials
- Impact on neighbours – loss of daylight, overlooking or privacy
- Street and area character – consistency with surrounding properties
- Location constraints – conservation areas, listed buildings or local policies
You will usually need planning permission for:
- Rear or side extensions
- Loft conversions with dormers
- Outbuildings in sensitive locations
- Changes of use
Some works fall under permitted development rights, meaning a formal planning application may not be required. However, these rights are limited by height, volume, footprint and location. Even though approval is normally not required, we recommend getting the council’s certificate. If you’re unsure what applies to your property, a professional planning permission assessment can confirm this early.
What Do Planning Permission Drawings Include?
Planning permission drawings typically include:
- Existing and proposed floor plans
- Existing and proposed elevations
- Roof plans (where required)
- Site or block plans showing the property in context
- Location plans based on Ordnance Survey data
For more complex projects — such as listed buildings or properties within conservation areas — additional documents may be required, including heritage statements or design and access statements.
Clear, accurate planning drawings reduce the risk of objections, requests for amendments or refusal and form the foundation for later technical design stages.
What Are Building Regulations?
Building regulations (often referred to as Building Control) set the minimum legal standards for how construction work must be carried out. They focus on safety, performance and usability. Even when planning permission is not required, building regulations approval almost always is.
Building regulations drawings explain how a project will be built to comply with UK Building Regulations. They are submitted to Building Control for approval before construction begins and provide contractors with clear, detailed instructions on how the work must be carried out on site.
What Do Building Regulations Drawings Include?
Building regulations drawings are far more detailed than planning drawings and typically cover:
- Structural safety – foundations, beams and load-bearing elements
- Fire safety – escape routes, alarms and fire separation
- Energy efficiency – insulation levels and thermal performance
- Ventilation and drainage – moisture control and air quality
- Accessibility and safety – stairs, guarding and critical dimensions
During construction, Building Control carry out site visits at key stages. Once the work complies with all requirements, a completion certificate is issued — a critical document for future sales, refinancing, or remortgaging.
Where Most Homeowners Get Caught Out
A common and costly misunderstanding is assuming that planning permission means a project is ready to build.
In reality, many delays and budget overruns happen before construction even starts, when it becomes clear that:
- Technical drawings are missing
- Structural design hasn’t been considered
- Building regulations requirements weren’t integrated early
- Planning-approved designs don’t work technically or financially
This often leads to redesigns, revised submissions, and increased costs.
Planning Tip for Homeowners (Free Feasibility Check)
Before submitting a planning application or paying for detailed drawings, it’s worth checking whether your proposal is likely to be approved and what constraints apply to your property.
At Studio Casa, we offer a free feasibility check to help homeowners understand planning risk, permitted development limits, and building regulations considerations early — helping avoid redesigns, delays and unnecessary costs.
👉 Check your project feasibility free of charge
Do I Need Both Planning Permission and Building Regulations?
Planning permission and building regulations are separate approvals. Obtaining one does not automatically cover the other.
In most cases:
- Extensions and loft conversions require both
- Internal structural works (such as removing a load-bearing wall) usually require building regulations only
- Small detached outbuildings may require planning permission but be exempt from building regulations in specific circumstances
Understanding which approvals apply — and in what order — is essential to avoid problems later.
How Planning Permission and Building Regulations Should Work Together
Ideally, planning permission and building regulations should not be treated as isolated stages.
- Planning approval confirms what you’re allowed to build
- Building regulations define how it must be built
When both are considered together from the start, projects run more smoothly and predictably.
At Studio Casa, we prepare planning permission drawings with building regulations and structural design already in mind. Once planning is approved, we develop the detailed technical drawings and calculations required for building control approval.
This coordinated approach:
- Reduces delays
- Prevents redesign after planning approval
- Improves cost certainty
- Protects homeowners throughout construction
Conclusion: Planning Permission vs Building Regulations
Planning permission ensures your project fits its surroundings.
Building regulations ensure it is built safely, efficiently and legally.
Many residential projects require both — and understanding the difference early can make the entire renovation process clearer, faster and less stressful.
Before investing time or money, it’s worth checking whether your ideas are realistic, compliant and likely to be approved.
If you’re planning an extension or loft conversion and want early clarity, we offer a free feasibility check. Share a few details about your property and your plans, and one of our experts will review your proposal and advise on planning risk, constraints and next steps — with no obligation.