Which of the following methods of mortar joint finishing has the greatest weatherability?

Mortar joint finishes impact water resistance and weatherability:

Concave joint is the most weather-resistant. The joint is compressed and curved inward, forming a

dense, compact surface that sheds water effectively.

Weathered joint slopes outward but is less compact than concave.

Raked joint is recessed and can hold water, less weather-resistant.

Extruded joint protrudes and tends to trap water and dirt.

Therefore, concave joints provide the best weather protection.

Reference:

NCARB ARE 5.0 Review Manual, Materials and Assemblies chapter

Masonry construction standards and detailing guides