strike

To strike is to trim and finish a mortar joint by drawing a tool across it after the mortar has begun to set but while it is still workable. The tool, usually a jointer or trowel, cuts away excess mortar that squeezed out during brick laying, leaving a clean, finished joint. The result can be flush with the brick face, slightly recessed, or finished at an intentional angle to shed water.

The timing of striking is critical. If done too soon, while mortar is soft, the joint collapses and bleeds. If done too late, after the mortar hardens, the tool drags and tears rather than cuts cleanly. The ideal moment is when the mortar has firmed enough to hold shape but remains plastic enough to cut without crumbling. This window typically arrives within 30 minutes to 2 hours of laying, depending on mortar mix, temperature, and humidity.

The angle and depth of the strike affect both appearance and performance. A recessed joint, cut 6 to 12 millimetres deep, sheds water reliably and creates visual shadow lines that accentuate coursing. A flush strike is faster but requires care to avoid a hollow appearance. Sloped joints (struck at a downward angle to one side) are common on commercial work and direct water away from the joint face.

Tool and technique

Strikers come in two main forms: the jointer (a U-shaped or V-shaped tool that cuts vertical and horizontal joints) and the slicker trowel or striking trowel (wider and flatter, used with a pushing or dragging motion). A pointing trowel and a brickset chisel can substitute in small repair work. The tool must be kept clean and slightly wet during use to prevent mortar sticking and dragging.

Striking is a fundamental skill in bricklaying, not a finishing afterthought. Poor striking leaves joints prone to water ingress, reduces the visual quality of the work, and can compromise the longevity of the wall. Because it requires hand control and judgment, it remains a skilled operation despite mechanisation elsewhere in masonry.