A hybrid cementitious mixture is applied to faults in the manhole to effectively plug gaps in risers and leakage from faulty seals and holes. The mixture can either be sprayed onto the manhole surface or hand applied by trowel. The mortar can be applied up to two inches thick and can be used as a stand-alone repair or to restore the manhole surface in preparation for epoxy coating.
This procedure restores the manhole to the correct surface plane. In addition, defects and infiltration due to faulty risers, chimney and frame are eliminated. After the defective manhole has been cut away, a new chimney is sealed to the cone. The chimney is cut to allow the frame to sit flush with the surface and a quick drying concrete solution creates a tight seal collar.
A cast-in-place concrete liner is designed to rehabilitate existing manholes. Modular forms are constructed inside the manhole structure, then a monolithic concrete pour between the form and the existing wall creates a solid manhole surface. The procedure is quick and requires no interruption of flow.