Sections for Planning Application in London
For a London planning application, a measured building survey must include floor plans, elevations, sections, and usually a site or block plan. Cross-sections are particularly important for extensions, basement excavations, and buildings with level changes.
Required Sections and Drawings
| Drawing Type | What to Include | Standard Scale | | --- | --- | --- | | Floor plans | Each floor showing rooms, wall thicknesses, door and window openings, structural elements, staircases | 1:50 or 1:100 | | External elevations | All 4 façades showing window and door positions, heights, architectural features, brickwork patterns (critical in Conservation Areas) | 1:50, 1:100, or 1:200 | | Cross-sections | Vertical slices showing floor-to-ceiling heights, floor-to-floor levels, roof pitch and structure, split levels, ground levels | 1:50, 1:100, or 1:200 | | Roof plans | Roof shape, chimneys, parapet walls, roofing material locations (essential for attic conversions) | 1:50, 1:100, or 1:200 | | Site or block plan | Property on Ordnance Survey base map showing boundaries, neighbouring buildings, access, topography | 1:500 or 1:200 | | Reflected ceiling plans | Ceiling features and heights (optional but helpful for complex projects) | 1:50 or 1:100 |
Key Requirements for London Planning
| Requirement | Detail | | --- | --- | | Scale bar | All drawings must include a linear scale bar | | Existing vs. proposed | Plans must show existing versus proposed works clearly | | Conservation areas | Exact mapping of architectural features, brickwork, and window styles required | | Rights of Light | Critical for assessments in dense urban rows | | GIA calculation | Required for calculating Gross Internal Area for CIL charges |
When Sections Are Required
| Project Type | Sections Required? | | --- | --- | | House extension | Yes — at least one cross-section showing extension relationship | | Loft conversion | Yes — section through roof and new dormer | | Basement excavation | Yes — multiple sections showing all levels | | Change of use | Yes — if levels or floor structure changes | | New build | Yes — site sections and building cross-sections | | Split-level buildings | Yes — to show level changes |
2025 Costs in London
| Property Type | Size | Cost (ex VAT) | | --- | --- | --- | | Small residential | Up to 2,000 sq ft | £450–£850 | | Medium residential or commercial | 2,000–10,000 sq ft | £850–£1,800 | | Large or complex property | 10,000+ sq ft | £1,800–£3,500+ | | Average measured survey | — | ~£1,400 (higher in London) | | Basic starting price | — | From £495 |
Price factors: property size, number of floors, complexity, internal and external survey, 2D versus 3D BIM required, site access difficulty, congestion charges.
Deliverables Format
| Format | Use | | --- | --- | | PDF | Standard for planning submission | | CAD-ready DWG | For architects and design teams | | Point cloud data | 3D laser scanning | | 3D BIM or Revit | Optional — from £550 |
Most London boroughs (Camden, Westminster, Tower Hamlets, etc.) require these surveys for validation, especially for complex or high-value projects.
Sections vs. Elevations: What's the Difference?
| Drawing | What It Shows | | --- | --- | | Elevation | Vertical view of a façade — front, back, or side | | Cross-section | Horizontal cut through the building — shows interior levels, floor thickness, roof structure |
You need both elevations and cross-sections for a complete planning submission.
Frequently Asked Questions
Q: How many cross-sections do I need for a London planning application?
At least one cross-section is typically required. For extensions, one section through the existing building and proposed extension is standard. Basement projects may require multiple sections.
Q: What scale should cross-sections be at?
1:50 for detailed design work. 1:100 for planning applications. Check your borough's requirements.
Q: Do I need sections for a simple house extension?
Yes — at least one cross-section is required to show the relationship between existing and proposed works, floor levels, and ceiling heights.
Q: What is the difference between a section and an elevation?
An elevation shows the outside of a building wall. A cross-section shows what is inside the building — like cutting it in half to see floor levels, ceiling heights, and roof structure.
Q: Can I submit drawings without a scale bar?
No — all drawings must include a linear scale bar. Submissions without scale bars will be rejected as invalid.
Q: Do I need sections for a basement planning application?
Yes — basement projects require multiple cross-sections showing all levels, retaining walls, waterproofing, and structural relationships to existing building.