Getting manholes on grade with a resurfaced street is often a difficult task. Heavy concrete risers are often used to build up the chimney so the cover and its frame can be raised, but those rings are cumbersome and require heavy machinery to install.As an alternative, Cretex Specialty Products offers the PRO-RING system, a series of lightweight expanded polypropylene (EPP) risers. These rings come in various shapes and sizes, including round, square and rectangular. The round rings are available in a variety of inner and outer diameter configurations, the latest version with an inner diameter of 24 inches and an
