Polyurethane vs Foam: When to Use a Structural Polyurethane Lining for Manhole Rehabilitation

Within infrastructure maintenance and rehabilitation, manholes play a crucial role in the proper functioning of sewer systems. Over time, these valuable assets can deteriorate due to environmental factors and lack of maintenance. Among the various options available to restore their structural integrity and extend their lifespan, Sprayroq’s SprayWall structural polyurethane lining has emerged as a highly effective and industry-leading solution when compared to foam-based methods. Below, we will explore the benefits of a structural polyurethane lining for manhole rehabilitation and understand why it surpasses foam-based alternatives.   

Strength and Durability 

Structural polyurethane linings offer remarkable strength and durability, making them an ideal choice for structural manhole rehabilitation. The lining material is specifically engineered to withstand heavy loads and typical municipal wastewater exposure. It forms a robust barrier that protects the manhole structure from further deterioration, preventing cracks, leaks, and infiltration of groundwater. Unlike foam-based solutions, which may lack the necessary strength, structural polyurethane linings provide long-lasting structural integrity to the manhole, ensuring its reliable performance over an extended period.  



One of the key advantages of structural polyurethane linings is their excellent ability to withstand hydrostatic pressures from a high groundwater table. Additionally, the lining can conform to irregular surfaces and adhere tightly to the manhole structure, creating a seamless and watertight seal. In contrast, foam-based solutions often struggle to maintain proper adhesion as they lack the sufficient tensile strength needed to resist hydrostatic pressures, leading to potential issues such as cracks or separation from the substrate. 


Chemical Resistance 

Manholes are exposed to a variety of corrosive substances and gases. Structural polyurethane linings possess exceptional resistance, protecting the manhole from corrosion and deterioration caused by these aggressive elements. The lining acts as a barrier, preventing penetration and safeguarding the underlying structure. Foam-based alternatives generally lack the same level of resistance, making them more susceptible to damage and requiring more frequent maintenance. 


Reduced Installation Time and Cost 

Another significant benefit of structural polyurethane linings is their efficient installation process, resulting in reduced downtime and reduced sewer bypass pumping costs. The lining can be applied quickly, ensuring minimal disruption to the surrounding area. With its excellent bonding and rapid curing time, the manhole can be put back into service much faster than with other methods, minimizing disruption to the community and leading to significant savings in labor and operational costs. 


Environmental Sustainability 

Structural polyurethane linings are formulated to be environmentally friendly. They contain no volatile organic compounds (VOCs), reducing the emission of harmful substances into the environment during the application process. For example, Sprayroq’s SprayWall lining is ANSI 61 certified for drinking water contact. Additionally, the long-lasting nature of the lining minimizes the need for frequent maintenance or replacement, resulting in reduced waste generation. In contrast, foam-based solutions may contain higher levels of VOCs and may require more frequent application, leading to a higher environmental impact.   

When it comes to structural manhole rehabilitation, SprayWall polyurethane lining is the obvious choice. Its exceptional strength, durability, adaptability, and corrosion resistance make it a superior option for protecting and extending the lifespan of your infrastructure assets. The reduced installation time and cost, coupled with the environmental sustainability of the lining, further solidify its position as the preferred solution in the industry. By leveraging the benefits of the SprayWall structural polyurethane lining, municipalities, and infrastructure managers can ensure the long-term integrity and functionality of their manhole systems, leading to improved efficiency and reduced maintenance expenses. 

For more information on how Sprayroq’s SprayWall Structural Lining can help rehabilitate your aging infrastructure, click here!