Repairing a highway drain by digging it up is slow, expensive and disruptive in roughly that order. UV-cured lining does the same repair from inside the pipe: a resin-impregnated liner is installed through an existing access point and cured in place with ultraviolet light, leaving a new pipe inside the old one. No trench, no reinstatement, and the carriageway back in use the same day on most jobs.
How UV lining works
- The line is cleaned and surveyed by CCTV so the defect, the bore and the connections are all known before anything is ordered.
- A liner cut to length is winched into position and inflated against the host pipe.
- A UV light train is drawn through it at a controlled speed, curing the resin as it goes.
- The liner is re-surveyed, and any lateral connections are reinstated by cutter.
The curing speed is the point. A UV liner cures in minutes rather than the hours a hot-water or ambient-cure liner needs, and the cure is driven by the light train rather than by pipe temperature, so it is far more predictable in cold and wet conditions — which, on a South West highway in February, matters.
Why it suits highways work
The road opens sooner
Traffic management is usually the largest single cost on a highway drainage repair, and it is charged by the day. Cutting a three-day excavation to a single shift removes most of that cost before any pipework is priced. Shorter occupancy also means fewer days of coned-off carriageway, which is a safety benefit as much as a programme one.
No excavation, no buried surprises
Trenching next to a live carriageway means dealing with unrecorded services, verge reinstatement and, on older roads, whatever previous generations left behind. Working inside the pipe avoids all of it. It also avoids the risk of undermining the pavement construction.
Less waste, less disturbance
A no-dig repair generates no arisings, no imported stone and no tarmac. There is no surface vegetation to lose and no spoil to cart away, which is straightforwardly cheaper as well as being the reason no-dig sits comfortably inside our ISO 14001 environmental management system.
A design life, not a patch
A correctly installed liner is a structural repair with a design life measured in decades, and its smooth bore usually improves flow compared with the pipe it replaced. Sectional patches are available where only a short length has failed.
Where it fits, and where it does not
UV lining is well suited to cracked, leaking, root-infiltrated or deteriorated storm drains and sewers beneath carriageways, footways and verges, and to extending the life of an ageing system that is structurally tired but geometrically sound.
It is not the answer to everything. A pipe that has lost line and level, collapsed, or been displaced — by a pile, by settlement, by an earlier excavation — needs the obstruction dealt with first, and sometimes needs open-cut. Heavy silt or protruding connections have to be cleared before a liner will sit properly. The honest sequence is survey first, then decide; anyone quoting a liner off a photograph is guessing. See CCTV sewer surveys and lining and no-dig repair.
For an example of the survey-first approach on a large culverted system, see our culvert surveys for AECOM on the Siston and Warmley flood defence scheme.
Working on the network
Highway drainage work is as much about permits, notices and liaison as it is about pipes. Exjet handles highways notices, client and stakeholder notification and the site-specific method statements in house, and we act as Principal Contractor for CDM where the scheme requires it. Our engineers are directly employed rather than subcontracted, which is what makes that paperwork match what actually happens on site.
Talk to Exjet about your drains
Exjet Services has been solving drainage and sewer problems across Devon, Cornwall, Somerset and Dorset since 1986, with commercial and planned work right across the South West. Our engineers are directly employed, and we are certified to ISO 9001, ISO 14001 and ISO 45001.
Related services: lining and no-dig repair, CCTV sewer surveys, planned drainage maintenance and civil engineering works. See also who we work with.
Blocked now? Ring 0800 328 6655 — answered any hour — or request a quote.