What is a mortar joint profile?
A mortar joint profile is the finished shape of grout lines between masonry units, created by tooling the mortar while it sets, which determines water drainage and visual character.
The profile of a mortar joint is the cross-sectional shape of the grout line between bricks, stone, or block. During installation, masons tool (shape) the joint while the mortar is still workable, creating different profiles that serve both structural and aesthetic functions.
Common joint profiles include:
- Concave: A rounded inward curve, the most water-resistant profile because rain sheds off and water cannot pool at the joint edge.
- Weathered: Slopes downward and outward from top to bottom, directing water away from the masonry face.
- Struck: Slopes upward and inward from top to bottom, the opposite of weathered and generally less effective at shedding water.
- Raked: Recessed horizontally with a flat bottom, popular for visual effect but requires careful detailing to prevent water entrapment.
- V-joint: A sharp diagonal V-shape, visually prominent but can trap water if not tooled precisely.
- Flush: Even with the masonry face, the simplest profile but offers no protection to the joint edge itself.
Joint profile directly affects performance. Profiles that slope or curve away from the wall face shed water more effectively and reduce freeze-thaw damage to the mortar. Recessed profiles can trap moisture and accelerate deterioration. Climate, exposure, and building use determine which profiles work best for specific projects. Proper tooling technique ensures the profile performs as intended and the masonry assembly remains watertight.