Planning Drawings vs. Building Regs Drawings: What’s the Difference?

Homeowners in Dorset often get confused between planning drawings and building regs drawings, because while they sound similar, they serve different purposes. If you’re planning a home extension or renovation in Dorset, it’s important to know the difference. In this guide, we’ll explain each type, why both matter, and how Rosenkelly Architectural Design can help.

What Are Planning Drawings?

Planning drawings are the plans you submit to the local council (like Dorset Council) to get planning permission. They focus on the design of your project – showing what you want to build and how it will look – but they don't show all the construction details.

Purpose: To illustrate your proposed design for approval. They show the size, shape, and appearance of your extension or new build.
What’s Included: Simplified site plans, floor plans, and elevation views (showing existing and proposed structures). These highlight how the project fits with your property and surroundings.
Level of Detail: They note basic dimensions and proposed materials but include no technical specs (no structural beams, insulation, etc.).

At Rosenkelly Architectural Design, we create clear planning drawings as the first step. Our team makes sure these drawings meet Dorset Council’s requirements and convey your vision. This makes the planning application process smoother, whether your project is a small extension or a new build.

What Are Building Regs Drawings?

Building regulations drawings (often just building regs drawings) are detailed plans that show how your project will comply with the Building Regulations – the UK’s building standards. These typically come after you secure planning permission (if required) and serve as the technical blueprint for construction.

Purpose: To show how your project will be built safely and to code. These plans are submitted for Building Control approval and guide your builder during construction.
What’s Included: All the technical specifications for the build. This includes foundation design, structural details (walls, roof, beams), insulation and ventilation, drainage, and placement of critical elements like electrical wiring and smoke alarms. In short, every important construction detail is covered.
Compliance Focus: They ensure the design meets all building rules for structure, fire safety, energy efficiency, etc. Unlike planning drawings, the focus here isn’t on looks but on meeting safety and quality standards.

At Rosenkelly, once planning is approved we prepare comprehensive building regs drawings for your project. We’ll specify the necessary materials and construction methods so building control can approve the plans and your builder knows exactly what to do.

Why Both Matter in Dorset Projects

In many Dorset projects, you will need both planning and building regs drawings because each serves a different purpose:

Planning vs. Building Control: These are separate approvals. Planning permission (from Dorset Council) gives you legal permission to build, while Building Control approval ensures the construction is safe and meets code. Skipping either one when it’s needed can lead to legal issues or unsafe results.
Local Rules & Safety: Dorset has specific planning policies (especially in conservation or coastal areas). Good planning drawings help show your design meets those local rules. Meanwhile, building regs drawings ensure the project is technically sound for local conditions and all safety standards (structure, fire, insulation) are addressed.
Avoiding Pitfalls: Having both sets of drawings keeps your project on track. For example, if you start building without approved building regs plans, inspectors can halt the work. Likewise, if a builder works only from planning drawings, missing technical details could cause costly errors. Using both means your project is legal, safe, and less likely to face delays.

Do I Need Both for My Project?

Different projects require different approvals. Generally:

Extensions: Most home extensions need both planning and building regs drawings. Some small extensions fall under permitted development (no planning application needed), but they still require building regs approval for the work.
Loft Conversions: Typically always need building regs drawings (for the new floor structure, insulation, stairs, etc.). Planning drawings are only needed if the conversion significantly changes your roof shape (or if your home is in a special designated area).
Garage Conversions & Internal Alterations: These usually don't need planning permission (since the outside of the house isn't changing much), but they do need building regs drawings to ensure the new living space meets standards (insulation, structural support for any new openings, etc.).
New Builds: Any new house or major rebuild will require both planning permission (with full design drawings) and building regulations approval (with detailed construction drawings).

If you’re unsure, ask an expert. Rosenkelly can quickly tell you which drawings and permissions your specific project in Dorset will need, so you don’t waste time or miss anything important.

How Rosenkelly Architectural Design Helps

As a local Dorset architectural design firm, we guide you through both stages:

Personal Guidance: We start with a friendly consultation to understand your project. We’ll advise whether you need planning permission, building regs approval, or both. Our advice is clear and honest — no unnecessary work if you don’t need it.
Planning Application Support: If you need planning permission, we handle the process for you. That means producing professional planning drawings, filing the application, and liaising with Dorset Council to get approval with minimal fuss.
Technical Drawings & Support: When it’s time for building regs, we create the detailed technical drawings your builder and the inspectors need. We coordinate with structural engineers for any calculations and ensure everything meets the latest standards. We also remain available during construction to answer questions and assist with inspections.

If you have a project in Dorset and want clarity on planning vs building regs drawings, get in touch with Rosenkelly Architectural Design. We’re happy to advise you and can provide a no-obligation quote to prepare the required drawings. Let us handle the paperwork and technical details, so you can focus on making your dream project a reality.

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