“CarbonSeal was recommended as an extremely strong system, that installs quickly
and protects against Hydrogen Sulfide gas found in most sewage systems…
We’ve always had good response from HJ3 and success with their systems.”

Adam S., Waste Water Contractor, Southwest USA

CARBONSEAL™: The Highest Strength and Resistance to Harsh Environments


Manhole repair

CarbonSeal Manhole Repair Systems are designed to strengthen your manholes to resist soil movement
and surface cracking, while protecting your manhole from harmful hydrogen sulfide gas exposure.

CarbonSeal lightweight and conforms to the inside surface of masonry and concrete manholes for
easy installation. Following installation, the systems are tested until determined to be pinhole free.

manhole repair

Flexible CarbonSeal Carbon Fiber
wrap bonded to inside of manhole

manhole carbonseal repair

CarbonSeal system spark tested to
assure a pin-hole free surface

CarbonSeal Systems are approved for use in waste water applications including

waste water application chart

Arizona Manhole Repair Case Study

Hydrogen sulfide gas, present in most sewage systems, rises up the manhole shafts and interacts with the bacteria found on the concrete, producing sulfuric acid. As the brick or concrete manholes degrade, spalling can occur. Not only is the structural integrity of the manhole threatened, but too much infiltration into the sewer system often leads to back ups and a costly shut down for clean up. 

arizona manhole repair

HJ3 removes degraded concrete, cleans the surface, and installs CarbonSeal quickset grout to resurface the manhole. The CarbonSeal carbon fiber system is then installed to strengthen the surface to restrict future cracking. CarbonSeal topcoat is then applied to seal and protect the manhole from future chemical attack.

manhole cfrp

manhole frp

repair manhole


Getting Started

The CarbonSeal products are designed with you in mind. To help you determine which CarbonSeal Manhole Repair System
is the best solution for your application, HJ3 provides the following tools:

  • Electronic Worksheets
  • Engineering Drawings
  • On-site Assessment
  • Testing Support
  • Case Histories
  • References

If you have a specific manhole application you would like reviewed, please contact an HJ3 Project Manager to schedule an on-site survey. Or request and complete the Manhole Repair Worksheet, and HJ3’s engineering team will diagnose the problem and send you engineered systems in a matter of days. Contact HJ3 at
877-303-0453 or fill out the form.

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