We have to replace 4 small retaining walls that are currently brick. They go down about 8-10" into the soil where they meet a cinderblock foundation 36" deep (below frost). Would it be ok to just put the new retaining walls on top of this existing foundation? The current walls are about 30-40 years old and are being replaced because they are leaning forward, but there is no settlement int he wall at all. Thanks.