What is batter in walls?

What is batter in walls?

Batter is the receding slope of a wall face: the face leans back, away from the viewer and towards the ground or water it retains. It is typical of retaining walls, quay walls and dry stone walls. The Dutch term is “sleping”, which also covers a wall that has started to lean backwards unintentionally, for example through settlement.

Reading a batter

Batter is given as a ratio or an angle. A batter of 1 in 20 means the face steps back 1 unit for every 20 units of height. That is 50 mm per metre of height, about 2.9 degrees from vertical. A 3 m high wall with a 1 in 20 batter is therefore 150 mm further back at the top than at the foot. Some sources write the ratio the other way round (rise to run, such as 20:1), so always check which way a drawing or specification means it.

Leaning the wall into the retained material improves its resistance to overturning. How much batter a wall needs depends on its type and design; for anything beyond a low garden wall, that is a job for a structural engineer.

Application: measuring and judging

  1. Measure with a plumb bob. Hang it from the top edge in front of the face and measure the horizontal distance to the wall at top and bottom. The difference divided by the height gives the batter.
  2. Build with a batter board. Fix a tapered strip to a straightedge so it thickens 10 mm per 200 mm of length. Hold it against the work: when the spirit level on its outer edge reads plumb, the face has the right batter.
  3. Designed or defect? A designed batter is uniform along the wall and free of cracks. Lean caused by settlement is usually local and comes with cracks, open joints or sticking windows.
  4. Monitor suspect walls. Mark fixed points, measure again after a few months and call in an engineer if the lean is increasing.
Designed batter or defect?Uniform along the wall, free ofcracks→Typical of a designed batterLean is local, with cracks, openjoints or sticking windows→Typical of settlement: monitor thewallLean is increasing when measuredagain after a few months→Call in an engineerWall leans forward→Not batter: batter always slopesback
How to tell a designed batter from unintended lean. A designed batter is uniform along the wall and free of cracks; lean caused by settlement is usually local and comes with cracks, open joints or sticking windows. Monitor suspect walls by marking fixed points and measuring again after a few months. Batter always slopes back, never forward.

Common mistake: mistaking a wall leaning forward for batter. Batter always slopes back.

Related terms

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