Building an extension in surrey and London. A Guide to what you need.
Planning what surveys and permissions you need | Building an extension in London and Surrey |
Planning what surveys and permissions you need.
Building an extension in London & Surrey — expert surveying by Cadmap
Thinking about an extension in London or Surrey ( including St George's Hill ) Cadmap provides end-to-end surveying and planning support to get your project from concept to completion — fast, accurate and compliant.
Meta description: Planning surveys for extensions in London and Surrey | Cadmap | Measured building survey London | Topographical survey Surrey | GPR utility survey London | St George's Hill surveys for extensions and planning permission
Why you need professional surveys before you build
Extensions may look straightforward on paper, but hidden problems and incorrect information can cause costly delays: inaccurate site boundaries, buried utilities, party wall disputes, or planning condition failures. Cadmap’s surveys give you the clear, defensible information your architect, structural engineer and local planning authority need.
Where we work
We cover all London boroughs and Surrey districts — domestic and small-commercial projects. We frequently work on properties in and around St George's Hill, Weybridge and surrounding Surrey areas, and understand the local planning expectations and typical constraints in these locations.
Surveys we provide for extensions
We provide a single point of contact and fast turnaround for all the surveys you’re likely to need:
Measured Building Survey (Floor plans, Elevations & Sections) — accurate as-built drawings for architects and building control.
Topographical Survey (Site survey) — contours, levels, boundaries, trees and features for site planning and drainage design.
Utility & Sub-surface Investigation (GPR / Electromagnetic) — locate buried services including non-metallic pipes so you avoid surprises during excavation.
CCTV Drainage Survey — condition and route of foul and surface water drains; essential when connecting into existing systems.
Boundary & Land Registry advice — mark up Title boundaries and provide evidence-ready plans for party wall discussions.
Party Wall Surveying / Notices — guidance on Party Wall Act procedures and preparation of Party Wall Awards (we liaise with specialist party wall surveyors if required).
Measured As-built for Planning Conditions — drawings and reports tailored to local authority planning conditions or Section 73 variations.
Permissions & approvals you’ll likely need (and how Cadmap helps)
Planning Permission or Householder Consent — we provide precise plans and site data to support your planning application and to answer planning officer queries.
Building Regulations Approval — measured drawings and technical data prepared for your structural engineer and building control submission.
Party Wall Agreements — we prepare boundary plans and can coordinate with party wall surveyors.
Drainage and Connection Consents — CCTV surveys, drainage plans and connection details for utilities and local authority approval.
Highways/Vehicle Crossover — if your extension affects access or on-street parking, we can prepare the necessary layout information.
Tree Protection & Ecology — we map protected trees and constraints on site; we can signpost local specialists for ecology reports if needed.
Cadmap works with your architect, structural engineer and planning consultant to make sure surveys feed directly into each permission application — reducing back-and-forth and speeding approval.
Our simple 4‑step process
Quick briefing call — you tell us the site, scope and timescales (we’ll confirm any previous records we need).
Site survey — we carry out measured, accurate surveys using total stations, laser scanning or GPR as required.
Deliverables & support — we supply CAD/DWG/ PDF drawings, topo data and a utility report suitable for planning, building control and contractors.
Post-delivery support — we respond to planning officer queries and provide minor revisions quickly.
Typical deliverables
DWG and PDF measured building plans, elevations and sections
Topographical survey with contours, spot levels and boundary points
Utility location plan and survey report (GPR findings)
CCTV drainage report with video and NDT logs
Photographic site record and tree/vegetation schedule
Why choose Cadmap
Local knowledge — regular projects across London boroughs and Surrey (including St George's Hill), so we know local quirks and officer expectations.
Multi-disciplinary expertise — from GPR and CCTV to measured surveys and planning-ready drawings.
Fast turnarounds — pragmatic, practical data that designers can use straight away.
Clear pricing and scope so you know what you’re buying.
Frequently asked questions
Q: Do I always need a topographical survey for an extension?
A: Not always. Small rear extensions sometimes only need a measured floor plan and elevations, but if you’re changing levels, adding drainage, or altering boundary treatments, a topo is usually needed.
Q: How do you find plastic pipes with GPR?
A: Ground Penetrating Radar combined with electromagnetic locators and our team’s experience can detect many non-metallic services, but no method guarantees 100% detection. We document confidence levels in our utility report.
Q: How long does a survey take?
A: Survey length depends on scope — many domestic surveys are completed on-site in a day with deliverables within a few working days.
Start your project with Cadmap
Planning an extension in London, Surrey or St George's Hill? Send us your address, a brief summary and any architect drawings you have and we’ll respond with a tailored survey proposal and pricing.
Contact Cadmap
Website: www.cadmap.co.uk
Email: info@cadmap.co.uk
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