Semtex Trenchless Solutions provides trenchless junction and lateral repair solutions for defective connections between lateral drains and main pipelines.

Depending on the defect, pipe size, junction angle and required repair length, we can install tophat liners, standard junction liners, lateral junction repairs (LJRs) and other localised lining systems. These methods seal and rehabilitate the connection without the need to excavate the junction.

Junction and lateral repairs can address:

• Leaking or defective lateral connections

• Root intrusion around the junction

• Cracked or fractured connections

• Failed mortar or poorly formed junctions

• Groundwater infiltration

• Wastewater exfiltration

• Soil loss around the connection

• Defects around reopened laterals following mainline CIPP

• Deteriorated sections extending into the lateral

• Localised damage within the mainline at the connection

• Failed previous repairs

• Open or poorly sealed junctions

Repair systems

The repair system is selected to suit the condition and geometry of the connection.

Tophat liners extend into the lateral and form a flange around the internal wall of the main pipe. Once cured, they create a sealed transition across the junction.

Standard junction liners are used where a localised repair is required around the connection without the full flange arrangement of a traditional tophat.

Lateral junction repairs (LJRs) can extend further into the lateral and may also reinforce the surrounding section of the mainline. This allows defects within both the junction and adjoining pipework to be repaired as one continuous installation.

Localised junction systems may also be combined with short liners or patch repairs where the defect extends beyond the connection.

Installation process

The mainline and lateral are cleaned and inspected before the junction is measured and prepared.

Roots, protrusions, failed materials and other obstructions are removed so the repair liner can sit correctly against the host pipe.

The resin-impregnated liner is loaded onto a specialist packer and positioned at the connection using CCTV guidance. The packer is then inflated, expanding the liner against the mainline and into the lateral.

Depending on the selected system, curing may be completed using:

• Ambient-cure resin

• Heat-assisted curing

• UV-LED light curing

Once cured, the packer is removed and a final CCTV inspection is completed to confirm the liner position, cure and finished connection.

Integrated rehabilitation

Junction and lateral repairs are commonly installed after mainline CIPP rehabilitation to create a sealed transition between the new mainline liner and the existing lateral.

They can also be used as standalone repairs where the main pipe remains serviceable but the junction or adjoining lateral has failed.

The repair method may be integrated with:

• Mainline CIPP lining

• Localised patch lining

• Short liners

• Robotic lateral reopening

• Pipe end sealing

• Additional lateral lining

Suitability depends on the mainline diameter, lateral diameter, junction angle, pipe condition, access and required repair length. Each connection is inspected and assessed before the repair system is selected.