City officials should too. Decision makers should also look closely at the manufacturer's mixing directions when selecting manhole coatings. Too often manufacturers promote a single solution to manhole rehabilitation without regard for the condition of the substrate. While odor may not be much of a problem, moisture certainly remains a curse to most epoxy manufacturers. Let's face it, most manholes are either wet, damp, moisture saturated, highly humid, or wet from dew, rain, or waterjet surface preparation.
Nothing ruins the coating properties and test results faster than moisture.
Add a trace of moisture in the long buried manhole and adhesion numbers can go from awesome to deplorable in one brush stroke. There are several epoxies that claim moisture tolerance or even the ability to be applied and to bond underwater to various substrates. Unfortunately, the performance of the so called underwater epoxies' varies greatly and city officials should literally put each such epoxy to a real and practical, on-site test. Some of the underwater epoxies can be applied to fresh concrete without the traditional 28-30 day waiting period as the concrete sets. I am surprised how often cement-based grouts and patches are recommended when light weight, moisture tolerant epoxy patching and filler products are alternative solutions.