Building regs guide · England & Wales

Building regulations drawings for extensions, lofts and conversions.

Building regulations drawings for your extension show how the project will actually be built — the construction detail your builder works to and building control signs off. They are different from your planning drawings, and almost every extension needs them.

Most building work needs two separate approvals. Planning decides whether you can build and how it looks; building regulations govern how it is built — the structure, insulation, drainage, ventilation and fire safety. If you want the full background before you read on, see our guide to building regulations for extensions explained.

Estimate my build cost→ Generate my free renovation report→ Check my project feasibility→ See what value it’ll add→ Instant design quote→ Do I need planning permission?→

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Fixed priceDrawings & calcs agreed up front
England & WalesDrawn to the right national standard
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Building regulations drawing package for a house extension, with construction sections through the walls and roof, insulation build-ups and structural details annotated.

What are building regulations drawings for extensions — and do you need them?

A building regulations package is a set of technical drawings and notes that prove your extension will be built to the standards the law requires. You will almost certainly need them for a rear, side or two-storey extension, a loft or garage conversion, a new opening, or any work that removes or alters a load-bearing wall.

Planning permission and building regulations are not the same thing. Even work that does not need planning permission — many single-storey rear extensions under permitted development, for example — still has to meet building regulations. If in doubt, our explainer covers exactly which extensions need approval.

What's included, and when you need them

What's included

  • Floor plans, elevations and cross-sections showing the construction
  • Wall, floor and roof build-ups, with insulation and energy efficiency
  • Structure — foundations, beams and load paths, coordinated with your engineer
  • Drainage, ventilation, and fire safety and means of escape

When you need them

For almost all structural work, yes — extensions, loft and garage conversions, removing load-bearing walls and forming new openings all need building regulations drawings. Building regulations apply across England and Wales, and we produce drawings for homeowners in both.

What a finished package looks like

See a real, anonymised example of the drawings we produce: Building Regulations Drawings example (PDF). It shows the level of construction detail building control expects for a typical extension.

Page from a finished building regulations package, showing a construction section cut through the wall, floor and roof with the insulation specification and beam positions marked.

Do you also need structural calculations?

Usually, yes. Any extension that removes a wall, adds a beam or forms a large opening needs structural calculations from an engineer alongside the drawings. We coordinate both so building control gets one complete, consistent package.

How Arkiplan produces and submits your drawings

We produce your building regulations drawings at a fixed price agreed up front — no hourly billing, no surprises. Your drawings are typically ready within three to six weeks of your design call, depending on the complexity of the project. See how it works or check pricing for your project.

Building regulations for extensions explainedBuilding notice vs full plansStructural calculationsLoft conversions

Building regulations drawings FAQ

What is the difference between planning drawings and building regulations drawings?

Planning drawings show what the project will look like and where it goes, for the planning decision. Building regulations drawings show how it will be built — construction, structure, insulation, drainage and fire safety — for building control.

Do I always need building regulations drawings for an extension?

For almost all structural work, yes — extensions, loft and garage conversions, removing load-bearing walls and new openings all need them, even when the work does not need planning permission.

What is the difference between 'full plans' and a 'building notice'?

A full plans application submits the drawings to building control for checking before work starts, giving you approval in advance. Our guide compares building notice vs full plans in detail.

Who approves building regulations drawings?

Building control — either your local council or an approved private building control body — checks the drawings and inspects the work on site.

Do I need structural calculations as well?

Usually, yes. Any project that removes a wall, adds a beam or forms a large opening needs structural calculations from an engineer alongside the drawings.

How long do building regulations drawings take?

With Arkiplan, your drawings are typically ready within three to six weeks of your design call, depending on the complexity of the project.

Ready to start your extension?

Book a free design call and we'll confirm the drawings and calculations you need, at a fixed price agreed up front.

Estimate my build cost→ Generate my free renovation report→ Check my project feasibility→ See what value it’ll add→ Instant design quote→ Do I need planning permission?→

All free, all online, all in about a minute — no obligation and no card needed.

Book a free design call

This guide is general information, not formal advice; building regulations and building control procedures change and depend on your specific project, property and local authority. We confirm the current position for your project as part of every job.