Is the grapevine-tooled joint as effective in resisting water penetration as a concave joint?
Grapevine, "V," and concave joints are all equally effective. These joints are tooled while applying pressure, which compacts the mortar and produces the most weathertight joint. These are the only joint profiles recommended for exterior use by the Brick Institute of America (BIA). Joints types such as weathered, beaded, struck, flush, raked, and extruded, which are formed by using a trowel or putty knife to cut mortar away without compacting it, are not recommended for exterior use. Joints that aren't tooled are more susceptible to separations along the bond interfaces because of the lack of compression. In addition to not sealing well, struck, raked, and extruded joints create ledges where water can collect.