Extension risers are used to raise access points on underground tanks and chambers to suit finished ground levels, ensuring safe access and correct cover depths once installation is complete.
Designed for use with GRAFseptic tanks, wastewater treatment systems, rainwater harvesting systems, soakaway crates, and pump chambers, these risers allow installers to accurately adjust invert and cover levels without altering the tank position.
This provides flexibility on site, particularly where ground levels change or where deeper installations are required.
Available in 300mm and 1000mm heights, GRAF extension risers are manufactured for strength, durability, and long-term underground performance.
They integrate seamlessly with compatible GRAF systems, helping maintain correct alignment, accessibility, and compliance with installation requirements.
A practical solution for achieving correct finished levels, GRAF extension risers simplify installation while supporting reliable long-term system operation.
