Spray-on epoxy coating requires that all active infiltration be stopped with concrete patching or chemical grout injection, and the entire host structure must be completely dry before applying the product. Heat generated during the curing process causes air bubbles behind the coating to expand and rupture, creating pinholes in the epoxy coating. Sewer gases seep through the pinholes and deteriorate the wall surface. Swelling and expansion of the concrete wall results in cracking and peeling - and deterioration of the host structure gets progressively worse.
Cement coatings do not stop active infiltration. Instead, cement coatings typically stress crack, and those cracks that form in pre-cast concrete or brick structures will re-crack any cement rehab coating product.
Fiberglass bag liners try to achieve the same effect as the Poly-Triplex liner system, but since they lack the patented, non-porous inner membrane, they do not stop active infiltration. Instead, active leaks are already present when the bladder is removed. The leaks push the liner away from the host structure, creating large bubbles that fill with water. Pinholes are formed, gases seep through, and deterioration of the structure continues.
Before applying polyurethane coating, all active infiltration must be stopped with concrete patching or chemical grout injection, and the entire host structure must be completely dry before applying the product. When drying, the polyurethane coating becomes hollow as it pulls off the host structure - hiding the real problem of future infiltration sheeting down behind the material undetected, and leaking into the structure where the coating ends. Continued infiltration and deterioration is inevitable.