Picote Concrete Removal at Heathrow Airport for BAM Nuttall Ltd

Project Snapshot

Client	BAM Nuttall Ltd
Sector	Aviation / Construction
Location	Heathrow Airport Tunnels, London
Services	Picote concrete removal, CCTV drain surveying, high-pressure jetting
Duration	1 month
Challenge	Hardened concrete blockages in live airport tunnel drainage, excavation impossible

Overview

When BAM Nuttall’s drainage investigation at Heathrow Airport uncovered hardened concrete blocking the tunnel drainage system, excavation wasn’t an option. It involves financial pre-qualification, health and safety assessments, a trial run, and then the work itself, carried out at night in a live tunnel handling 500 vehicles an hour.

LDF passed every stage and delivered the full project over the course of a month, removing hardened concrete blockages from Heathrow’s tunnel drainage system using Picote milling technology. Following completion, BAM Nuttall Ltd invited us back to work on additional tunnels.

The Challenge

BAM Nuttall Ltd had been working at Heathrow since 2014, upgrading the main tunnel into the central terminal area as part of a major infrastructure improvement programme. Alongside road resurfacing and upgrades to ventilation, lighting, and fire suppression systems, the project uncovered a significant drainage problem: hardened concrete had accumulated within the tunnel’s drainage system, restricting flow and posing a long-term infrastructure risk.

In a standard commercial setting, concrete blockages of this nature would typically require excavation. At Heathrow Airport, that wasn’t an option. The tunnel carries up to 500 vehicles an hour, aircraft-adjacent infrastructure in one of the world’s busiest aviation environments. Digging up the tunnel floor would have caused operational chaos and enormous cost.

The solution had to be non-invasive, precise, and deliverable entirely at night without disrupting daytime airport operations.

Our Approach

BAM Nuttall had already commissioned a CCTV survey to locate and document the concrete within the drainage system. With the problem mapped, they needed a contractor who could remove it without breaking ground.

LDF’s Operations Supervisor Craig Norton attended the site to assess the scope and confirm that Picote concrete removal was the right solution. Following successful financial and H&S pre-qualification, we were offered a one-night trial, which we passed. The full project ran for a month from that point.

Picote milling is a robotic, internal pipe milling system designed specifically for blockages that can’t be cleared by jetting alone: hardened concrete, grout, slurry, and large solid deposits. The machine uses a combination of twister brushes, a heavy-duty 3mm metal panel, and a front drill head fitted with star carbides to break down and remove blockages from within the pipe without any surface excavation.

We worked one drainage chamber at a time, using strategic CCTV resurveying throughout to confirm successful clearance in each area before moving on. High-pressure jetting was used between stages to flush debris and water through.

The operational constraint was strict: works ran from 9pm to 4:30am each night, with one side of the dual carriageway tunnel closed at a time while traffic used the other. A full rest break was built into every shift between midnight and 1am. LDF’s team briefed at 7:30pm each evening and finished before the morning traffic build-up began.

The Outcome

All targeted blockages were successfully removed over the course of the one-month project. The tunnel drainage system was fully cleared and resurveyed to confirm clearance. The airport’s infrastructure was restored without any excavation, surface disruption, or impact on daytime operations.

Following completion, BAM Nuttall Ltd engaged LDF to return and carry out the same works on additional Heathrow tunnels, the clearest possible measure of a successful delivery.

About This Project Type

Picote milling is used where blockages are too hard or dense to clear by jetting, but excavation isn’t viable, typically in aviation, transport, and infrastructure environments, heritage and listed buildings, and high-traffic commercial sites where closure time must be kept to a minimum.

The process requires precise CCTV survey work before and during removal to confirm clearance chamber by chamber. LDF carries Picote equipment as a standard part of its commercial drainage capability and has delivered Picote projects under H&S pre-qualification, security vetting, and extended anti-social hours working conditions.

Work with LDF

Call our 24-hour helpline: 0800 612 2179
Or visit: london-drainage.com/commercial/

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