When You Need a Topographical Survey in North West London
You definitely need one for:
- Planning permission: most LPAs expect accurate site plans, especially beyond minor works
- New builds, replacement dwellings, significant extensions, outbuildings
- Sloping or irregular sites: where levels affect access, drainage, massing
- Conservation areas: near heritage assets and sensitive neighbours
- Sites with trees: BS5837 arboricultural constraints require accurate topographical data
- Projects needing SuDS, flood-risk assessment, or drainage design
- Brownfield land: with likely underground utilities and services
North West London (Brent, Harrow, Barnet) has a diverse mix of residential, commercial, and heritage properties. Accurate topographical data is essential for any design that interacts with ground levels, drainage, or boundaries.
Costs in North West London (2025)
| Site Size | Typical Price (ex VAT) | | --- | --- | | Up to 0.25 acre (small residential plot) | £595–£600 | | 0.25–1 acre (medium site) | £795–£1,200 | | 1–3 acres (larger or complex sites) | £1,500+ | | 3+ acres | POA (quote required) |
Prices are ex. VAT. London may add travel and complexity premiums. Total cost depends on site size, terrain complexity, access, and required deliverables.
What Affects Cost and Timeline
- Site size and complexity: steep slopes, dense vegetation, urban features increase time
- Detail level required: contour interval (0.5m vs 1m), whether elevations or 3D BIM needed
- Access and occupancy: occupied or furnished sites are slower
- Utilities mapping: optional PAS 128 GPR survey adds cost and time
- Deadline urgency: some firms offer expedited service
Standard Deliverables
| Deliverable | Format/Details | | --- | --- | | 2D site plans | DWG (AutoCAD) + PDF at 1:200 or 1:500 scale | | Building footprints | With threshold, eaves, and ridge levels | | Spot levels and contours | Contour interval specified in brief | | Boundaries | Fences, walls, kerbs | | Trees | Trunk diameter, canopy, height (BS5837) | | Drainage and utilities | Covers, visible utilities, street furniture | | Coordinates | OS National Grid coordinates and georeferencing | | Optional | 3D point cloud, BIM model (RVT/IFC) |
All surveys are georeferenced to OS National Grid with OD heights and comply with RICS standards.
Turnaround Time
| Phase | Typical Duration | | --- | --- | | Booking and lead-in | 5–10 working days | | Fieldwork | ~1 day for ~5,000m² (standard open site; longer for complex sites) | | Drafting and QA | 1–2 working days | | Total | 2–3 weeks from instruction |
Expedited service available on request.
Coverage: Brent, Harrow, Barnet
We provide topographical surveys throughout North West London — including:
- Brent: Wembley, Kilburn, Willesden, Harlesden, Neasden, Dollis Hill
- Harrow: Harrow-on-the-Hill, Harrow Weald, Stanmore, Kenton, Pinner, Northolt
- Barnet: Finchley, Edgware, High Barnet, Chipping Barnet, Mill Hill, Hendon
Plus all surrounding NW, N, HA, and EN postcode areas. Surveyors also cover the Home Counties (Hertfordshire, Surrey, Essex, Buckinghamshire).
Frequently Asked Questions
Q: When do I need a topographical survey in NW London?
You need a topographical survey for most planning applications in Brent, Harrow, and Barnet, especially new builds, major extensions, replacement dwellings, and sites with trees or complex topography. North West London boroughs typically require accurate site plans showing levels, boundaries, and tree positions.
Q: What contour interval do I need?
1m contours are standard for planning applications. Drainage and earthworks design typically require 0.5m contours. Confirm with your design team.
Q: What accuracy can I expect?
RICS standards require ±50mm accuracy for detail points. All surveys are georeferenced to OS National Grid with OD heights.
Q: How long does a topographical survey take in NW London?
Booking lead-in is typically 1–2 weeks. Fieldwork is 1 day for small to medium sites. Drawing production takes 1–2 working days. Total: 2–3 weeks from instruction. Some firms offer expedited service.
Q: Do I need a topographical survey for an extension in Brent, Harrow, or Barnet?
If your extension involves significant earthworks, drainage changes, or affects boundaries, a topographical survey is typically required by the planning authority. For minor single-storey extensions, a measured building survey may suffice — confirm with your local planning department.