Why walls lean
Earth pushes outward on a wall. A wall that leans back moves its own weight over the soil it retains, so the push has to overcome more mass before the wall could tip. The steeper the wall, the more its stability relies on something other than its own weight: geogrid, steel or a footing.
Batter by system
Crib walls typically stand at a batter of around one in four to one in six, which is why they need room in plan. Keystone and Allan Block units set a smaller batter automatically, often around one in eight to one in twelve. Keymass and rock walls are battered to the engineer's design. Sleeper walls are usually near vertical and rely on their posts and footings. Reinforced block cantilevers are vertical.
What it means for the site
A battered wall occupies more ground at the base than at the top. On a tight boundary that can decide the system. On an estate batter it is invisible. The engineer and the survey resolve it early, which is one reason we ask for boundaries and levels before we recommend a system.
