320mm Polypropylene Riser (Black)

The 320mm Polypropylene Riser is the standard solution for adjusting the height of an inspection chamber (manhole) during installation. When your chamber base is buried deep in a trench, these risers sit securely on top of the base (or each other) to bring the access point up to the finished surface of your garden, driveway, or patio. Each riser provides a vertical lift of 200mm and features a ribbed design for maximum structural integrity against ground pressure. Designed for “shallow access” applications, these risers are lightweight and easy to handle compared to traditional concrete rings. They feature a simple “click-fit” or push-fit system with an integral sealing ring (sold separately or included depending on the pack) to ensure the shaft remains watertight and prevents groundwater from leaking into the drainage system. Once the desired height is reached, the top riser is finished with a 320mm circular or square cover and frame. Made from 100% recycled polypropylene, this riser is both environmentally friendly and resistant to the corrosive chemicals and salts found in the soil. Modular & Stackable: Each riser adds 200mm of height, allowing you to easily build up the chamber shaft to the exact ground level required. High Structural Strength: The ribbed outer wall provides excellent resistance to lateral ground pressure and prevents the chamber from shifting or collapsing. Lightweight Construction: Much easier to transport and install than concrete alternatives, significantly reducing labor time and the need for heavy machinery. Easy to Cut: If the final riser is slightly too high for your finish level, it can be easily cut to size with a fine-toothed saw. Standard Compatibility: Specifically designed to fit our 320mm 5-Inlet Chamber Base and all standard 320mm manhole covers and frames.