The Clearway Drainage Systems Limited Top Hat provides a seal between the main pipeline and a lateral connection and is comprised of a resin impregnated, fiberglass laminate, shaped to fit within a lateral service connection and wrap around the main pipeline. Thus sealing both the connection and providing a smooth transitional flow between the lateral pipe and the main sewer. Epoxy is utilised in addition to the resin to provide a permanent adhesive, water tight seal.

A robotic device, controlled via cable from a mobile control centre, transports and installs the seal. The procedure is monitored continuously via CCTV. The seal is cured in place using ultra-violet (UV) light within 10 minutes of exposure. Both equipment and material are produced by the same manufacturer. The fiberglass laminates are wet-out with UV-light reactive resin at the manufacturer’s wet-out facility and transported in light proof bags to the site, which eliminates mixing resins in the field.

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  • 10 minute UV Cure
  • Install in live flow (under most circumstances)
  • No mixing of resin in the field (factory wet-out and delivered enclosed, in a gel-state)
  • Resin is only reactive to UV-light, therefore no premature set-off as with ambient cure systems
  • Dual cameras monitoring the positioning of the top hat within the host pipe and a second internal camera monitoring the insertion within the lateral through the transparent bladder unit
  • Glass reinforcing increases structural strength, mitigates shrinkage and allows for a thin wall
  • The thin wall allows for future rehabilitation of the remaining pipe segment
  • Fully structural repair designed as a 50-year solution
  • Tapered edge is bonded to the host wall
  • Fraction of full length lining cost or excavation cost
  • Extensive performance history (12+ years in the U.S. and Globally with over 50,000 installs worldwide)
  • Can be incorporated with a UV-Spot Repair for a full circumferential repair
  • DIBt – German National Technical Approval for both top hat and short liner


The material is an ECR (E-Glass, Corrosion Resistant) fiberglass mat pre-impregnated with either Palatal P-92 Polyester light reactive resin, or Atlac E-Nova RE 3475 Vinyl Ester light reactive resin. The wet-out procedure is performed at the manufacturer’s plant in Austria (in controlled conditions) and is partially cured during the wet-out procedure transforming the resin into a gel-state for safe handling and transportation (no hardeners are required for onsite field mixing). The resin and glass laminate configuration, as a whole, eliminate any need for inner and outer coatings. The manufacturer provides a specially designed A/B Epoxy for application over the outside of the resin at the laminate ends to create an adhesive seal between the repair and the host pipe. The material is available in a variety of wall thicknesses and can be overlapped for extended lengths (typical repair 500mm).

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Typically, resin does not have adhesive properties. To ensure a water-tight seal between the sectional liner and the host pipeline wall, a manufacturer-supplied A-B Epoxy system is supplied and incorporated into the repair procedure. When the glass laminate (gel-state) is wrapped on the bladder, the A-B epoxy paste is mixed on a flat surface and applied towards the laminate ends.

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The applicator (silicone bladder) extends beyond the laminate edge therefore creating a beveled edge against the host wall, compressing the epoxy between the host wall and resin laminate. The result is a sealed, smooth transition to the sectional liner.


In addition to the top hat and short liner patching capabilities of the unit it is also equipped with a 3 Kw electrically powered cutting head. This cutting head is capable of removing deposits and reopening lateral connections in pipes ranging from 150 – 600mm diameter. Due to the unit being powered by electricity there is no requirement for large tow compressors, as with air powered cutters. This minimises both the noise levels and site footprint, along with the reduced fuel consumption reducing the carbon footprint.

The units pan and tilt camera facility and Wincan recording ensure that the finished repair is inspected upon completion and a report in the Wincan format provided to the client. The works are carried out from start to finish with a single vehicle.

The requirement of only one access manhole and a robot range of 100 metres minimises traffic management and disruption, added to this the fast cure times and reduced noise levels and the advantages begin to stack up!

Top Hats & Lining

Clearway offer the latest development in high performance no dig repair solutions that provide a quick and easy method of repairing damaged drainage and sewerage pipes.

The repair system is installed internally and therefore eradicates the need for costly, disruptive and time consuming excavation work.

  • Repairs pipes with a bore diameter of between 70 and 560 mm
  • Repairs can be made to most pipe materials including UPVC, clay, cast iron, ductile iron, stainless steel, pitch fibre and asbestos cement
  • Permanent and watertight pipe repairs
  • Environmentally and ecologically friendly
  • Tested to WRc and international standards
  • 10 year material guarantee
  • Inflammable so ideal for airports, hospitals, stations and other public areas