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Manhole Rehabilitation Q&A: The Top 5 Questions from Our Webinar

Following NASSCO guidelines, we recommend removing ladder rungs during rehabilitation for two important reasons:

  • Safety concerns: Steps can deteriorate over time, creating hazards for utility workers and maintenance personnel
  • Security issues: Removing rungs prevents unauthorized access to the sewer system

While this is ultimately the owner’s choice, removing ladder rungs is considered best practice in the industry for both safety and long-term system integrity.

When dealing with failing linings:

  • Failed linings must be completely removed before applying new coating systems
  • The root cause of failure should be determined to prevent recurrence (poor adhesion, incompatible resurface, inadequate surface preparation)
  • The removal method depends on the existing coating’s condition:
    • Water blasting is often ineffective on intact linings
    • Abrasive blasting or chipping hammers may be required
  • Each situation requires individual assessment – there’s no one-size-fits-all approach

For manholes with inches of erosion or compromised rebar, we recommend:

  1. Using our composite system with cementitious repair mortar to reinstate the original surface and restore structural integrity
  2. Applying structural epoxy coating for protection against corrosion and I&I
  3. For extensive damage, our trowel-grade materials can be applied up to 1″ thick per lift
  4. Multiple lifts may be required depending on corrosion severity

A thorough condition assessment is critical to determine the best approach for your specific situation.

The recommended mil thickness for our structural epoxies is based primarily on depth, not diameter. We calculate based on resistance to hydrostatic forces, which increase with depth:

  • 0-25 ft depth: 125 mils minimum
  • 26-70 ft depth: Up to 200 mils
  • 70 ft depth: Even greater thickness required

Our technical team can help calculate the exact specifications for your project based on its unique parameters.

For optimal performance in composite systems, we recommend using Epoxytec’s proprietary cementitious materials with our epoxy coatings. Here’s why:

  • Our materials are extensively tested for adhesion compatibility
  • We know the exact properties of our cementitious repair mortars
  • This ensures predictable performance in challenging environments

For infiltration control materials like chemical grouts or hydraulic water stops, we may consider alternatives after proper evaluation, but for cementitious repair mortar or overlay, we strongly recommend using our tested materials.

Have more questions about manhole rehabilitation or our structural epoxy solutions?
Contact your local representative.

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Questions answered by Director of Epoxytec
Vaughn O’Dea