Both buildings rest on what was once a tidal flat, and the excavating caused the church to begin settling into its site unevenly.
I discovered this because the wet spot from where it drains was causing the house to settle unevenly, and when I had the foundation checked the tech told me to get that water away from the house.
But the wall had become a problem this spring, the memo said, as sections over the westernmost portion shifted and settled unevenly, and substantially.
This can occur if the house is settling unevenly.
This step is important, because a poor subgrade will allow the concrete slab to settle unevenly, causing cracks or fissures.