Adjustable foundation wall arrangement

An adjustable foundation wall arrangement having first and second foundation walls running generally parallel to each other and a third foundation wall being disposed between the first and second foundation walls. The first and second foundation walls are preferably prefabricated and the third foundation wall is prefabricated in two portions. On site, one of the third foundation wall portions is aligned to the first foundation wall and the other of the third foundation wall portions is aligned to the second foundation wall. This alignment typically leaves a small space between the inner ends of the third foundation wall portions. This small space, preformed in the shape of a receptor for a key stud, is at least partially filled by the key stud to tie the third foundation wall portions to each other. Alternatively, or preferably in combination with the key stud, a cap tie connects the third foundation wall portions to each other. The cap tie includes two ends, and each end abuts a cap plate, one of which in turn connects to the first foundation wall and the other of which connects to the second foundation wall.