Road & sub-base level surveys
Sub-base and binder checked against the road design before the next layer goes on.
As-laid service surveys
As-laid surveys of drainage and ducts, before they're buried
Record it while you can still see it. We survey pipes, chambers and ducts in the open trench with an RTK GNSS rover and photos, then give you an as-laid drawing and data you can hand to the adopting authority, the client or the next contractor.
In short: an as-laid survey records the exact position and level of pipes, chambers and ducts while the trench is still open. We measure them with an RTK GNSS rover, photograph each section and deliver an as-laid drawing in DWG and PDF with a CSV of every point, usually within two working days.
- Records
- Position, level, depth, photos
- Accuracy
- 10–20 mm plan, 20–30 mm level
- Drawing
- Within 2 working days
- From
- £325 per visit
What goes on the as-laid record
- Pipe runs with crown levels at intervals and at every change, and calculated inverts from the pipe size.
- Chambers and manholes: centre positions, cover levels and the pipes in and out.
- Fittings: bends, junctions, connections, rodding eyes and lateral positions for each plot.
- Ducts and utilities: position, depth below finished level and which service is which.
- Crossings and clashes with other services, with the clearance between them.
- Geotagged photos of every section before it's covered.
Why record before backfill
Drainage and ducts are where as-built drawings are least reliable. Runs get moved on site to miss a service or a tree root, depths change, laterals go in where the plot drainage actually came out. Months later, someone redraws the design and calls it the as-built. Then the adoption inspection, a blocked lateral or a new connection finds the truth.
A measured record taken in the open trench, with photos, removes the guesswork. It also protects the groundworker: if a level or a fall is ever questioned, there's a dated record of what was laid.
Check the falls while you still can
Because the levels are recorded as the pipe goes in, we can flag a run that's flatter or steeper than the design, or a backfall, the same day, while it's still cheap to put right.
Typical uses
- Section 104 sewers and Section 38 highway drainage for adoption packs.
- Street works records of what was laid in the highway.
- Private drainage, soakaways and attenuation on housing and commercial sites.
- Utility ducts for power, telecoms and EV charging.
- Land drains and water supply pipes on farms and estates.
Need the finished roads, covers and plots recorded at handover as well? See as-built surveys.
How as-laid recording works
Drawings and control
The drainage or services layout and the site control, so the record lines up with your design.
Call-out or programme
We agree how you'll tell us a run is ready and book visits around the drainage gang.
Record in the trench
Positions, levels and photos taken while the gang carries on further along.
As-laid drawing
DWG, PDF and CSV within two working days, with any fall or position issues flagged straight away.
What an as-laid survey doesn't cover
We record what's visible in the open trench. Services already backfilled need tracing by a utility survey, and the inside condition of a pipe needs a CCTV survey. We don't enter trenches that aren't properly supported or battered; recording is done from the surface with the rover pole, so safe trench support is the site's responsibility. Invert levels calculated from crown levels are labelled as calculated.
Other survey services
See the as-laid survey cost guide for prices.
Tarmac depth surveys
Before-and-after scans that map the thickness actually laid, across the whole road.
Plot & oversite surveys
Slab flatness, brickwork to drawing and drain collar positions, checked plot by plot.
As-built surveys
Finished roads, kerbs, drainage covers and plots recorded, with as-built drawings in DWG and PDF.
Floor flatness surveys
Slabs and screeds scanned edge to edge and checked against SR1-SR3 or your flatness class.
3D measured building surveys
Millimetre-accurate floor plans and elevations for kitchens, extensions and architects.
Topographical surveys
Levels, contours, boundaries, buildings and trees for planning and design, with the full 3D scan.
Dimensure Design Audit
Groundworks and civils drawings reviewed before you dig, on any project: problems found on paper.
Garden surveys
Levels, walls, steps, trees and drains surveyed for garden designers, landscapers and homeowners.
Drone surveys
Aerial mapping tied to RTK GNSS control: scaled orthophotos, levels and contours for whole sites.
Stockpile volume surveys
Every heap of stone, topsoil and spoil measured by drone, in cubic metres and tonnes.
Earthworks volume surveys
Cut and fill against design or a previous survey, topsoil strip depths and muck-shift checks.
Site progress surveys
Monthly drone records of the whole site, compared with last month, for valuations and reports.
GNSS setting out
Site control on Ordnance Survey grid, and pegs for earthworks, drainage, roads and plots.
Pre-start condition surveys
Roads, kerbs, walls and neighbouring buildings recorded by scan, drone and photo before work starts.
Drone roof surveys
Close-up roof inspections without scaffold, with measured roof areas and pitches if needed.
Reporting from your survey data
Already have a scan or your engineer's levels? We process your data and report against design, no visit needed.
As-laid surveys near you
Questions we get asked
What is an as-laid survey?
A record of exactly where a pipe, duct or cable was laid and at what level, taken while the trench is still open. Once it's backfilled, the only way to know where it really went is to dig it up or trace it, so a survey before backfill is the most reliable record you'll ever have.
What do you record?
Pipe runs and their crown levels at regular intervals, bends, junctions and connections, manhole and chamber positions with cover levels, duct positions and depths, crossings with other services, and geotagged photos of each section. Invert levels are calculated from the crown level and the pipe size and are marked as calculated.
Why is an as-laid record needed?
Sewer and highway adoption (Section 104 and Section 38 agreements) need accurate as-built records of drainage. Street works on the highway need records of what was laid and where. Housebuilders and management companies need to know where private drainage and ducts run. And when something goes wrong years later, a measured record with photos saves a lot of digging.
How accurate is an as-laid GNSS survey?
Typically 10 to 20 mm in plan and 20 to 30 mm in level in open sky, checked against site control on every visit. In deep, narrow trenches or close to buildings where the sky is blocked, we transfer levels down from an open point and say so on the record.
Can you come out at short notice when a trench is open?
That's the point of the service, because trenches can't be left open waiting. We agree a call-out arrangement with the site, and on a regular programme we book visits around the drainage gang's programme. Recording is usually done while the gang carries on further along the run.
Does this replace a CCTV drainage survey?
No. We record position and level from the surface before backfill. A CCTV survey after completion checks the inside of the pipe for joints, debris and defects, and adopting authorities often ask for both. Our record and a CCTV survey together make a complete adoption pack.
Book a scan or ask a question
Send the drawing, the location and when you need it. We reply the same working day with a fixed price.