What is a Structural Epoxy Liner?

A structural epoxy liner is a high-strength, ultra-thick protective coating engineered to restore and line underground water and wastewater infrastructure. These systems are designed as applied and bonded linings that work together with the host substrate to hold back hydrostatic pressure and other forces, while also delivering corrosion protection in below-grade environments.

In addition to their bonded performance, structural epoxy liners provide a safeguard against installation variances. If small areas inadvertently become unbonded, the cured film’s exceptional mechanical strength allows it to span gaps and hold back low-pressure forces such as inflow and infiltration (I&I). This unique combination of adhesion and free-film strength ensures long-term durability in demanding conditions.

Thin Film Protection is Not Enough

Traditional thin-film coatings are not designed to withstand the combined acid attack coupled with backside forces on the liner or film. Structural epoxy liners deliver a balance of properties needed for long-term performance—including acid resistance against hydrogen sulfide (H₂S) corrosion, strong bonding to saturated-surface-dry (SSD) concrete or masonry, and the ability to prevent leaks that otherwise would persist through annular spaces.

With ultra-high build application and verifiable engineering design, structural epoxy systems provide more than protection—they deliver structural lining capability that extends service life while reducing the need for costly replacements.

When Should I Consider a Structural Epoxy Lining System?

Structural epoxy lining systems are ideally suited for sanitary sewer collection systems (manholes and lift stations), stormwater structures, and water distribution assets where I&I, corrosive environments, or external forces threaten asset integrity.

Typical thicknesses for vertically buried structures range from 125 mils (1/8″) to 250 mils (1/4″), depending on the depth and design requirements, and are determined using established engineering standards such as ASCE Manual of Practice 92. For horizontal buried pipelining, thicknesses would be determined by engineered calculations depending on the forces to be accounted for.

Structural epoxy linings create an engineered lining system that restores structural integrity, mitigates I&I, and safeguards critical assets—offering a cost-effective rehabilitation solution that endures for decades.

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Want a deeper dive into the engineering behind structural epoxy lining? Download our white paper Understanding Structural Epoxy Liners for a comprehensive look at terminology, applications, design considerations, and performance insights.