Most push and helical piers install from outside, with excavation along the affected footing, then the soil and landscaping are restored. Some piers and most wall stabilization happen inside the basement. The engineer's plan and your home's layout determine the mix; the inspection covers exactly what gets disturbed.
More detail
Where the work happens depends on the repair and the failure location, and we walk through it specifically at the inspection so there are no surprises. For settlement repaired with piers, the most common approach is exterior: the crew excavates a hole down to the footing at each pier location around the outside of the affected area, installs and load-tests the pier, then backfills. Exterior excavation means temporary disruption to landscaping, and sometimes to a patio, walk, or deck, which we account for in the scope and restore as part of the job. In some situations, piers are installed from inside, breaking through the basement slab at each location, which is the approach when the settlement is under an interior footing or when exterior access is blocked by a driveway, addition, or property line. Interior pier work means slab cutting and patching but spares the landscaping. Bowing-wall stabilization is mostly an interior operation: carbon-fiber straps and steel I-beams are installed from inside the basement against the wall, with little or no exterior digging. Wall anchors are the exception, since they require excavation out in the yard to set the earth anchors in stable soil, which is why they need open yard access. Slab leveling is the least invasive of all, just small injection ports through the slab surface. The engineer's plan, your home's construction, and the site constraints determine the exact mix of interior and exterior work, and the written proposal spells out what will be excavated or cut, and how it will be restored, so you know precisely what to expect before the crew arrives.