Layer lines

Layer lines are the horizontal ridges visible on the face of a 3D-printed concrete element, formed by the profile of each successive deposited bead. Their pitch equals the layer height, and their depth depends on the nozzle geometry, the extrusion rate and how much each layer deforms under the weight of the ones above it.

In practice

Layer lines are usually treated as the intended appearance of printed concrete, and much of the market for printed furniture and facade elements is built on that look. They also have practical consequences. Horizontal grooves collect dust and organic growth on exterior faces and guide rainwater sideways rather than shedding it, so the detailing around them matters for durability. On interior surfaces they complicate cleaning and prevent flush contact with other components. Measuring dimensional tolerance is less obvious than on a flat face, since the reference plane sits somewhere between ridge and valley, which needs to be agreed before an element is checked against drawings.

Related terms

• Layer height — the vertical pitch that sets the spacing of the lines.
• Surface finish — the wider question of how the printed face is left or worked.