Introduction

We slipline both pressure (force mains) and gravity lines. Hinterland Group delivers sliplining as one of our in‑house trenchless rehabilitation methods, providing structural renewal with minimal surface disruption while maintaining service continuity with engineered bypass when required. See our in‑house trenchless program on the Pipe Rehabilitation and Services pages.

What sliplining solves

• Restores structural integrity and flow in aging host pipes without open‑cut replacement.

• Limits inflow/infiltration in gravity systems and controls exfiltration/leakage in pressure systems.

• Upsizes selectively where feasible and improves hydraulic performance by removing rough, deteriorated host surfaces.

• Reduces community and traffic disruption relative to dig‑and‑replace.

Materials we install

Hinterland Group installs sliplining with the following liner materials, matched to the hydraulic duty, host pipe condition, and project constraints:

• High‑Density Polyethylene (HDPE): fused segmented sticks for robust, fully restrained joints; widely used for pressure mains and gravity lines.

• Fiberglass‑Reinforced Polymer (FRP): high stiffness for large diameter gravity/culvert applications and sections requiring corrosion resistance.

• Fusible Polyvinyl Chloride (FPVC): restrained joints with PVC hydraulics for pressure applications and gravity segments requiring tight bends and smooth interior surfaces.

All material selection, fusion/assembly, QC documentation, and submittals are performed by Hinterland crews; we self‑perform trenchless methods to propose the most cost‑effective option for each asset. Reference: Pipe Rehabilitation.

Annular grouting (required for sliplining)

After inserting the liner, we pressure‑grout the annular space to:

• Lock the liner in place and transfer loads from the host pipe and surrounding soil.

• Prevent groundwater migration along the annulus and eliminate buoyancy in high water tables.

• Restore bedding/support where hosts have voids.

Our submittals define grout mix design, placement strategy (ports/spacers, lift heights, pressures), temperature control, and monitoring. Grout logs are included in closeout documentation.

Service reinstatement and appurtenances

• Gravity laterals: locate via pre‑CCTV and records, expose as needed, install saddles/tees to the new liner, and verify with post‑CCTV.

• Pressure services and fittings: reconnect tees, bends, and valves with restrained joints; pressure‑rate all appurtenances to system MAOP.

• Structures: coordinate with manhole rehabilitation where required; see Repair & Replacement for integrated mechanical/electrical services.

Acceptance testing and QA/QC

Hinterland’s inspection and testing program combines field QA with owner‑specified acceptance tests:

• Gravity systems: post‑construction CCTV inspection, leakage checks at reconnections, and deflection/ovality verification for thermoplastic liners as specified.

• Pressure systems: hydrostatic pressure test and leakage criteria per contract; where potable, disinfect/sampling as specified by the owner.

• Documentation: test reports, grout logs, fusion logs (if applicable), as‑built CCTV, and redlines. Our Inspection team provides certified operators and robotic cameras for deliverables.

Typical diameter ranges and use cases

Hinterland sliplining is applied from small mains to large trunk lines. Actual limits are project‑specific and validated during design and submittals; our broader trenchless program routinely addresses small to very large diameters across the Southeast.

Host diameter band	Common use cases	Notes
4–24 inches	Small pressure mains (water/force mains), gravity collectors	Often HDPE or FPVC with fully restrained joints for pressure duty; gravity reinstatements via saddles.
30–60 inches	Municipal gravity interceptors, storm drains	FRP or HDPE liners with staged annular grouting; coordinate with manhole rehab.
66–108 inches	Large trunk sewers, culverts, stormwater conduits	High‑stiffness liners with engineered grouting plans and multi‑port placement; traffic‑sensitive corridors.

Note: Hinterland’s trenchless portfolio includes large‑diameter capabilities across methods (e.g., CIPP up to 108" shown on state service pages), and sliplining design envelopes are selected to overlap those ranges where appropriate. See examples and program scale on CIPP South Carolina and CIPP North Carolina.

Execution differences: pressure vs. gravity

• Pressure (force mains)

• Fully restrained joints (fused HDPE/FPVC) and restrained fittings.

• Line stops/bypass to maintain service; in‑house bypass planning and operation per Repair & Replacement.

• Hydrostatic testing to owner criteria; surge analysis as specified.

• Gravity

• Grade and capacity checks during design; hydraulic modeling as required.

• Lateral mapping, reinstatement, and manhole interface coordination.

• CCTV acceptance and inflow/infiltration reduction verification via flow monitoring where specified.

Integration with PRIME delivery

Sliplining is executed within Hinterland’s PRIME model:

• Pipeline Rehabilitation: sliplining alongside CIPP, pipe bursting, geopolymer spincast (Services).

• Repair & Replacement: integrated lift station, mechanical, and electrical scope to support tie‑ins and system controls (Repair & Replacement).

• Inspection: pre‑/post‑CCTV, cleaning, and condition assessment (Inspection).

• Maintenance: scheduled cleaning/assessment to protect asset life (Maintenance Plans).

• Evaluation & Assessment: risk, prioritization, and lifecycle planning (Evaluation & Assessment).

Geographic coverage and rapid response

Headquartered in Riviera Beach, FL, with a secondary wetout facility in Morganton, NC, Hinterland mobilizes rapidly across the Southeast for planned work and emergencies. See Markets We Serve.

Why Hinterland for sliplining

• All trenchless technologies performed in‑house for unbiased method selection and single‑source accountability (Pipe Rehabilitation).

• Integrated bypass pumping and electrical teams to keep systems online during construction (Repair & Replacement).

• Certified inspection crews and advanced CCTV deliverables for transparent QA (Inspection).

• Proven delivery on small to multimillion‑dollar municipal programs; see project portfolio on the Home page.