Horizontal cracks are very different than vertical cracks. In most circumstances, vertical cracks are non-structural, whereas horizontal cracking often indicates the foundation wall is moving inward (which is a structural concern). This may be caused by a "pour line" in the concrete, or unusually high soil pressures against the foundation wall. Whether they leak or not, they need to be repaired properly before they become a larger problem. These cannot be repaired from the interior only, they typically need a pressure reduction repair (and waterproofing) on the exterior, as well as being stabilized on the interior.
When your wall has moved inward, we need to reduce the lateral pressures. This can be accomplished by removing the native materials and backfilling with washed rock.
We use a specially designed 2x8 wall to help stabilize your wall. Beware of cheaper and weaker 2x6 walls competitors may use.
The completed wall is ready for the homeowner to insulate, vapour barrier and drywall. A few inches of floor space has been lost, but you can now rest assured your wall is stable.