Manholes are essential for accessing and maintaining underground infrastructure, but for those managing them, they often represent recurring headaches. From infiltration and soil washout to failing covers, the issues are rarely minor, and left untreated, they can quickly compromise entire sewer or stormwater systems. If they fail, the damage doesn’t stop at the structure itself. Roadway collapse, public safety risks, and regulatory penalties can follow, often with a high price tag. For municipalities, utilities, and property managers, understanding why manholes deteriorate, when intervention is needed, and the most effective repair methods is critical to protecting both budgets and infrastructure. Continue reading to learn why manholes deteriorate, when they need repairs, and how polyurethane injection Manhole Rehabilitation from Mr. Level works.
Why Do Manholes Deteriorate?
Manholes age just as any other structure. However, exposure to different factors can cause or accelerate the process of deterioration. These factors include:
- Roadway Vibrations: The vibrations of traffic from the roadways where manholes exist on or near can lead to the settlement of support soils around the structure.
- Inflow and Infiltration: As manholes age, the sealant around joints or mortar between bricks may deteriorate. The loss of these crucial sealants can allow inflow and infiltration (also called I/I). I/I is when liquids begin to flow into the manholes through unintended paths, leading to faster aging, as well as further infiltration and soil loss. Additionally, I/I may occur through cracks within the structure.
- Cracks: Cracks can occur within the concrete or bricks that comprise manholes, as well as around the manhole cover. These cracks may point to soil loss or settlement. They also can allow inflow and infiltration.
- Soil Loss: Soil loss from around manholes can accelerate issues such as I/I and cracks within and around the structure. The loss of these support soils can lead to their shifting, which causes cracks and can even lead to their full-blown failure. Sinkholes, roadway collapse, public safety, and fines are all a risk with extreme soil loss and void development.
When Do Manholes Need Repair?
Manholes need consistent maintenance to continue functioning as intended. Additionally, they may also need repairs to prevent failures and extend their lifespan. Manhole rehabilitation should happen when:
- Soil loss is evident through structural signs such as cracks in the manhole or in the above asphalt or concrete, as well as when soil is entering into the sewer or stormwater system manholes connect to.
- Soil loss is evident through geophysical testing such as Ground Penetrating Radar (GPR), Dynamic Cone Penetrometer (DCP) testing, soil samples, or any other geophysical testing.
- Inflow and infiltration is occurring. When I/I occurs, especially for extended periods of time, it speeds up the deterioration of the structure.
Manhole Rehabilitation from Mr. Level
Fortunately, Mr. Level has a solution for the soil loss and I/I that can occur around manholes: manhole rehab via polyurethane injection. The process is simple, minimally invasive, and can seal the structure from I/I, prevent further soil loss, and fill voids that are a detriment to the manhole. Here is how it works:
- Small holes are drilled into the concrete or asphalt that surround the manhole cover.
- Through the holes, polyurethane is injected in its liquid form. The injections may occur directly through the holes, or rods may be placed, depending on how deep the injections need to reach.
- The polyurethane reacts and expands. During the expansion, the polymer seals the manhole, fills voids in the soil, and reestablishes soil contact that supports the entire structure.
- Final geophysics testing may be conducted to ensure the repair is completed to its full ability. The drilled holes are filled, completing the service.
When manholes need repair, services should be done as early as possible. And when cities, municipalities, and utility companies are deciding who should conduct the service, consider Mr. Level for manhole rehabilitation in the Ohio area. Our team’s service is cost effective, less disruptive than alternative options, and can extend the lifespan of manholes. Contact us today to schedule.