Structural storm drain lining for pipes that have lost the structural capacity to carry loads safely.

WHEN STRUCTURAL LINING IS REQUIRED

The difference between structural lining and standard rehabilitation lining.

Standard CIPP liners are designed to assume some structural contribution from the host pipe — they provide waterproofing and joint sealing but rely on the host pipe for a portion of the structural load capacity.

Structural CIPP liners are designed for fully deteriorated host pipe — specified to carry full soil weight, groundwater hydrostatic pressure, and traffic loading with zero contribution from the host pipe. These liners are thicker and are manufactured to higher structural property standards.

LiningWorks specifies structural versus standard liner based on camera-documented pipe conditions — wall loss measurements, structural defect extent, and pipe depth and loading conditions specific to each project.

PIPE CONDITIONS REQUIRING STRUCTURAL LINING

When camera inspection calls for structural rather than standard liner specification.

Structural lining is indicated by specific pipe conditions that preclude reliance on any remaining host pipe structural contribution.

• Significant crown wall loss from H2S or chemical corrosion

  When camera and inspection data show crown material loss exceeding approximately 30% of original wall thickness, structural liner specification is required to maintain the designed factor of safety.
• CMP with advanced invert corrosion and wall thinning throughout

  CMP storm drain systems with advanced corrosion often show wall thinning at the invert and bottom half of the pipe — requiring structural liner specification when thinning is severe.
• Deep pipe installations under heavy vehicle traffic with deteriorated host pipe

  Pipes at depth under high-traffic loading — parking decks, loading docks, heavy-haul roads — require structural liner specification when the host pipe cannot reliably contribute to load resistance.
• Partial collapse conditions in large-diameter storm drain mains

  Large-diameter storm drain mains with partial crown collapse require structural liner specification that accounts for spanning the collapse section and carrying full loading with no host pipe contribution at the collapse point.

BEFORE & AFTER

Municipal CMP culvert — structural CIPP lining avoided complete replacement.

A municipal utility district in the Charlotte region had a 24-inch CMP culvert under a collector road that had developed advanced invert corrosion — camera inspection showed wall thinning across approximately 70% of the pipe invert, with complete perforation at one location.

LiningWorks specified a structural CIPP liner designed for zero host pipe contribution, accounting for the measured wall thinning and the 4-foot depth under collector road loading. Installation was completed through headwall access points. Post-installation camera confirmed full liner bond throughout. The road was not closed at any point during installation.