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Gunpowder Outfall Sewer Transition Structure and Manhole Rehabilitation

Warren’s epoxy rehabilitates sewer while meeting aggressive schedule and minimizing disruptions

Client Type





Baltimore, MD

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At a Glance

  • Aggressive schedule
  • Concrete and brick manholes
  • Corrosion
  • Invert lining
  • Manhole repair
  • Outfall chamber
  • Residential neighborhood
  • Surface replacement
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Our master applicator, A&W Coatings, used Warren Environmental’s epoxy coating system to line sewer structures and manholes, including lining 15 feet up and downstream of the invert of the outfall structure. The concrete and brick surfaces were extremely deteriorated, especially within the manhole chamber where rebar and wire mesh were exposed. Large sections of the brick wall were replaced with new bricks and then lined with our epoxy. The outfall structure required 500 mils of Warren’s epoxy, which was applied in a single coat.

The project involved a variety of challenges that A&W Coatings had to overcome, including minimizing the disruption to the surrounding residential neighborhood. The team accomplished this by implementing overnight shifts when necessary. Another challenge involved the acceptable downtime of the system. The flow could only be stopped for 40 minutes at a time, which required unique methods to prep, coat, and inspect the application within those intervals.

The project was completed in 2015 and both the outfall structure and manholes were re-inspected in 2018 by a NACE II inspector. Results showed that the structures were in great condition and had no defects.


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