SprayWall® Structural Lining: Engineering with Unmatched Strength

In the realm of trenchless technology, finding a rehabilitation solution that offers not only ease of installation but also exceptional structural integrity is paramount. Sprayroq’s SprayWall structural lining system stands out as the industry-leading choice for rehabilitating underground assets such as manholes, large-diameter pipes, and other critical infrastructure. Below, we will dive into the technical capabilities of SprayWall, focusing on its strength and durability, and compare these features with traditional Class A concrete to illustrate why SprayWall is the superior choice for your trenchless needs. 

Understanding the Structural Capabilities of SprayWall 

SprayWall is a spray-applied, 100% solids polyurethane coating designed to provide both structural enhancement and corrosion resistance. One of the most remarkable features of SprayWall is its impressive mechanical properties, which are crucial for the longevity and reliability of underground infrastructure. 

Compressive Strength

SprayWall boasts a compressive strength exceeding 18,000 psi, as measured by ASTM D 695 standards. To put this into perspective, typical Class A concrete has a compressive strength of about 4,000 psi. This means that SprayWall offers more than four times the compressive strength of standard concrete allowing it to, when applied in a manhole for example, act as its own independent structure as demonstrated by a 2021 University of Texas at Arlington study. Such high compressive strength ensures that SprayWall can withstand enormous hydrostatic, soil, and traffic loads, which is essential for underground applications where pressure is a constant factor. 

Tensile Strength

With a tensile strength greater than 7,450 psi, according to ASTM D 638, SprayWall significantly surpasses the capabilities of Class A concrete, which typically exhibits a tensile strength of around 400 psi. This superior tensile strength is critical in environments where forces might cause materials to stretch or pull apart. For underground structures, the ability of SprayWall to resist these forces means a reduced risk of cracks and structural failure, ensuring a longer service life and fewer maintenance needs. 

Third-Party D-Load Testing

In addition to ASTM testing, SprayWall has also demonstrated exceptional load-bearing performance in other rigorous testing environments. For example, according to third-party D-Load testing, which assesses the ability of a pipe or structure to withstand deformation under external loads, SprayWall significantly reinforces the host structure. The enhanced load-bearing capacity ensures that rehabilitated structures can handle increased service loads without compromising their structural integrity. 

D-Load Rating

The Advantages of Polyurethane over Concrete 

While concrete has been a staple in construction for decades, polyurethane systems like SprayWall offer several distinct advantages that are particularly beneficial in trenchless applications: 

Abrasion Resistance: One of the standout properties of SprayWall is its exceptional abrasion resistance. SprayWall’s ability to withstand such conditions is quantified by its impressive ASTM D4060 Taber Abrasion test results, demonstrating minimal weight loss under severe abrasive forces. This is particularly important in underground environments where sediment or debris flow can cause significant wear and tear over time, which is particularly beneficial in applications such as sewer lines and drainage pipes where the flow of gritty materials is constant.

Corrosion Resistance: SprayWall is inherently resistant to the chemicals typically found in municipal raw sewage flows. This chemical resistance is something that concrete cannot match, as it is prone to degradation from typical water and wastewater environments, leading to costly repairs and reduced lifespan.

Rapid Cure Time: One of the standout features of SprayWall is its rapid curing time. Within seconds of application, SprayWall is tack-free, and within an hour, it has already achieved its initial cure and can be returned to service. This quick turnaround is crucial for minimizing downtime in essential services, a benefit that concrete, with its lengthy curing period, cannot offer.

Seamless Application: SprayWall is applied in a continuous process, creating a seamless, joint-free lining that eliminates weak points and potential leak paths. This monolithic lining significantly enhances the watertightness of the structure, a critical factor in maintaining the integrity of underground systems. 

SprayWall in Action: Real-World Applications 

The practical applications of SprayWall are as diverse as they are impressive. For instance, in the rehabilitation of aging manholes, which are often subjected to both environmental stress and biogenic attack, SprayWall not only restores structural integrity but also adds decades to the service life of the asset. The product’s rapid application and cure times mean that traffic disruptions and service downtimes are kept to a minimum, a crucial consideration in urban settings. 

Moreover, SprayWall has been employed in larger-scale projects, such as lining large-diameter pipes and culverts where its ability to conform to irregular surfaces and bond securely with existing materials has been invaluable. These applications demonstrate not only the versatility of SprayWall but also its capability to deliver results where traditional materials might fail. 


In the field of trenchless rehabilitation, the structural capabilities of a lining material are critical to the success and longevity of the project. Sprayroq’s SprayWall lining offers superior strength, durability, and longevity compared to traditional concrete solutions. With its impressive compressive and tensile strengths, rapid cure time, and resistance to biogenic and environmental stressors, SprayWall provides an advanced, reliable, and cost-effective solution for maintaining and enhancing the integrity of underground infrastructure. For infrastructure managers looking to invest in the future of their assets, choosing SprayWall means opting for a solution that not only meets but exceeds the structural demands of trenchless rehabilitation.