Must the entire annular space be grouted when sliplining with HDPE pipe?

While grouting is not required for every application, generally it is recommended that it be done. Grouting the entire annular space is good practice. It generally represents only 3 % to 5% of the overall project cost.

The annular space must be grouted when the condition of the existing pipe no longer permits it to support soil loads or live loads. Lf the ground water level rises above the host pipe grouting may be required to provide adequate resistance to collapse caused by external hydrostatic forces acting on the liner pipe. More.

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