An extension needs two sets of drawings: one for planning (how it looks), one for building control (how it’s built). Here is what goes in each.
Location plan
- What it shows
- The house and its surroundings, the site edged in red, often at 1:1250 or 1:2500
- For
- Planning
- Usually drawn by
- A plan supplier, architect or designer
Site plan
- What it shows
- The house, the extension and the boundaries, closer up
- For
- Planning
- Usually drawn by
- An architect or designer
Plans and elevations
- What it shows
- The rooms from above, and each side as it will look
- For
- Planning and building control
- Usually drawn by
- An architect or designer
Building regulation drawings
- What it shows
- How it’s built: structure, fire safety, ventilation, damp-proofing, insulation, drains
- For
- Building control (full plans)
- Usually drawn by
- An architect, architectural technologist or designer
Structural calculations
- What it shows
- Foundations, beams and lintels; whether a wall holds the house up
- For
- Building control
- Usually drawn by
- A structural engineer
| Drawing | What it shows | For | Usually drawn by |
|---|---|---|---|
| Location plan | The house and its surroundings, the site edged in red, often at 1:1250 or 1:2500 | Planning | A plan supplier, architect or designer |
| Site plan | The house, the extension and the boundaries, closer up | Planning | An architect or designer |
| Plans and elevations | The rooms from above, and each side as it will look | Planning and building control | An architect or designer |
| Building regulation drawings | How it’s built: structure, fire safety, ventilation, damp-proofing, insulation, drains | Building control (full plans) | An architect, architectural technologist or designer |
| Structural calculations | Foundations, beams and lintels; whether a wall holds the house up | Building control | A structural engineer |
Who can draw them?
In England, anyone can submit a planning application; no architect has to sign it. But only someone on the Register of Architects can call themselves an architect, so check the register if that’s who you’re paying for.
What the building regulation drawings cover
A
- What it covers
- Structure: foundations, walls, beams
B
- What it covers
- Fire safety: escape, and fire spreading to next door
C
- What it covers
- Damp and moisture
F
- What it covers
- Ventilation, such as trickle vents in new windows
L
- What it covers
- Insulation and energy use
| Approved Document | What it covers |
|---|---|
| A | Structure: foundations, walls, beams |
| B | Fire safety: escape, and fire spreading to next door |
| C | Damp and moisture |
| F | Ventilation, such as trickle vents in new windows |
| L | Insulation and energy use |
Before you pay for drawings
- Ask whether the price covers the planning drawings, the building regulation drawings, or both
- Ask who arranges the structural engineer
- Ask for drawings your builder can price from
What would your job cost?
Describe it, and see a typical price for your area. Then ask builders who do this work.
Read next
How we wrote this
Written by Structa. The rules come from the official pages below. General information, not legal advice.
- GOV.UK: Making an application (the plans a planning application needs) (checked 16 October 2026)
- GOV.UK: Approved Documents (the building regulations guidance) (checked 16 October 2026)
- ARB: Information for the public (the Register of Architects) (checked 7 October 2026)
- IStructE: Find a structural engineer (checked 7 October 2026)
- CIAT: Chartered Architectural Technologists (checked 7 October 2026)