Joined: July 2004
||Posted: 29 Dec. 2018,12:17
1 - The peat is the most likely cause of the ground movement, but poor backfilling beneath the patio is also likely to be implicated
2 - A floating slab, dowel-tied to the house foundation, with appropriately positioned movement joints
3 - I'd be sorely tempted to eliminate the retaining wall by lowering the level of the patio. Rely on steps/terraces/ramps to transition from house to patio, but lose all that unnecessary height.
Site Agent - Pavingexpert