toothing

Toothing is the practice of leaving alternate bricks projecting from the end face of a wall, creating a rough stepped edge rather than finishing it smoothly. These projecting bricks, called tooths, are left in place specifically to act as mechanical keys when the wall is extended later. The gaps between them receive fresh mortar and new bricks, which lock around the toots and bind the old wall to the new work without relying solely on surface adhesion.

The pattern follows a consistent rhythm. If a wall is built to a temporary stopping point, every other course has its end brick left protruding roughly 4 to 6 inches beyond the face line. The bricks not used as tooths are cut flush or slightly back. This creates a sawtooth profile when viewed end-on. When building resumes, the mason cuts the new bricks to fit around these projections, and fresh mortar beds them in. The result is a stronger bond than would occur if the new wall simply butted against a smooth, finished face.

Toothing is less common now than it was historically, because modern site planning and continuous construction sequences allow walls to be built through in one operation. However, it still appears in renovation work, phased developments, and situations where a wall must stop temporarily at a predetermined point. Some jurisdictions favor toothing for structural continuity; others specify a flush finish with planned keys cut into the mortar bed later. The choice depends on masonry standards, the nature of the delay, and whether temporary weatherproofing of the face matters.

The term toothing comes directly from the resemblance of the stepped edge to teeth. Older masonry texts and specifications use it without explanation, suggesting it was once universal practice. The verb to tooth means to leave these projections intentionally during construction. Poor toothing, bricks left too short, too far back, or spaced irregularly, defeats the purpose and can weaken the joint where walls meet.