Our experience with most basement waterproofing projects is very simple.
Most cracked foundations are the result of one or more of the following:
The concrete being placed or poured should have been reinforced horizontally as well as vertically. Without STEEL REBAR reinforcement being part of the component for concrete, it is virtually useless (particularly when you have hydrostatic pressure coming from your 8′ deep soil, clay or aggregate).
The lack of reinforcement will cause the concrete to separate or break at the point where it has the most hydrostatic pressure applied (mother nature).
It will start out as a small crack and if not rectified will eventually turn into a larger crack with freezing and moisture from the fall through the winter. The size of the crack will increase and allow water to penetrate through. This type of defect in the concrete foundation should only be repaired from the outside. You want to stop the water from the outside.
In our opinion, repairing or injecting a type of epoxy for the interior of the concrete is only a temporary fix and not long-term basement waterproofing. Water will find its way in somewhere else.
With basement waterproofing, usually we have to excavate the problem area or areas right down to the footing.
We then check the weeping tile to make sure that after we leave the area that it is in good shape. If it too is defective, we must repair it.
We will clean and grind the area. After locating the crack or cracks, we grind a wedge type groove in this area to a depth of at least 5/8″. We then tuck point a dry mortar (non-shrink type), such as a pre-hydrated mortar or a hydraulic mortar.
Both should be monitored and brushed while mortar is setting to ensure no cracks are visible. We then install a water membrane and if required for concrete block, we will parge the wall first, before we install our water membrane.
If it is a stone foundation, we will tuck point all defective mortar joints prior to installing a trowel on water membrane to ensure that all voids and protrusions are completely covered, creating a 100% seal for the foundation.
We backfill soil/clay/aggregate and return all landscaping, interlock or steps back to original state.
We back up our basement waterproofing with a minimum 20-year warranty.