The mortar between your bricks does far more than hold them together. Its shape determines how well the wall sheds rain, how it ages, and how the whole surface looks from the street. Understanding the types of mortar joints helps you spec the right finish for a new project or match the existing joints when you repoint an old wall. Some profiles are built to fight water in harsh climates, while others exist purely for looks. Choose wrong and you can invite moisture problems that crack masonry within a few winters. Here is how each common joint works and where it belongs.
Why Joint Profile Matters
A mason “tools” the mortar joint by pressing a shaped tool along the wet mortar to compact and form it. That tooling does two things. First, it compresses the mortar surface, making it denser and more weather-resistant. Second, it shapes the joint so water either runs off or pools. In climates with freeze-thaw cycles, a joint that traps water lets moisture seep in, freeze, expand, and slowly destroy both mortar and brick. So the profile is not just decoration; it is a durability decision.
Weather-Resistant Joints
Concave Joint
The concave joint is the most popular and most weatherproof profile in the United States. The mason presses a rounded jointing tool into the mortar, creating a smooth, curved-in surface. That curve compresses the mortar tightly and channels water down and away from the wall. It hides minor irregularities well, which is why builders favor it for everything from homes to commercial buildings. If you are unsure what to use in a wet or cold climate, concave is the safe default.
V-Joint
A close cousin of the concave joint, the V-joint is tooled into a sharp inward V shape. It sheds water nearly as well and gives a crisper, more defined shadow line that many people find attractive on contemporary brickwork. It performs strongly in rain and freeze-thaw conditions and is a solid choice for exterior walls where appearance matters.
Weathered Joint
The weathered, or struck, joint is angled so the top of the joint is recessed and the bottom is flush with the brick below. This downward slope sheds water exceptionally well, arguably better than any other profile. It takes skill to tool consistently from below, but on exposed walls in severe weather, it is one of the best performers you can specify.
Joints to Avoid in Wet Climates
Struck Joint
The struck joint is the inverse of the weathered joint: the bottom is recessed and the top is flush, creating a small upward-facing ledge. That ledge collects water, which makes it a poor choice for exterior walls in rainy or freezing regions. It is easier to tool from above, so it shows up on interior work and in dry climates where water is not a concern.
Raked Joint
A raked joint is created by removing mortar to a uniform depth, leaving the joint deeply recessed. The deep shadow lines create a dramatic, textured look prized for accent walls and certain architectural styles. The downside is significant: the recess creates a ledge that holds water and exposes more mortar surface to the weather. Raked joints belong indoors or in dry climates, and even then they need quality mortar and careful sealing.
Decorative and Specialty Joints
Flush Joint
The flush joint is exactly what it sounds like: mortar finished level with the face of the brick, with no tooling beyond a simple wipe. It is quick and gives a clean, minimal appearance. Because it is not compressed by a tool, it is less weather-resistant than a concave or V-joint, so it is best for interior walls or surfaces that will be painted or rendered over.
Extruded or Weeping Joint
The extruded joint, sometimes called a weeping or squeezed joint, is left as it oozes out when the brick is set, with no tooling at all. It produces a rustic, old-world look popular on traditional and farmhouse styles. It offers little weather protection and is not suited to harsh climates, but in the right setting it delivers a lot of character.
Beaded Joint
The beaded joint uses a special tool to form a raised, rounded bead protruding slightly from the wall. It creates a refined, formal appearance once common in historic and high-end masonry. Because the bead projects outward, it is vulnerable to chipping and weathering, so it is mostly reserved for protected or decorative interior applications and restoration work.
Matching Joints When Repointing
If you are repointing an older wall, the goal is to match the existing joint profile so the repair blends in. Examine an undamaged section, identify the profile, and use the matching tool. Equally important is matching the mortar mix. Old soft-lime mortar paired with a modern hard Portland-cement mix can actually crack the historic brick, because the rigid new mortar does not flex the way the old wall was built to. When in doubt on a historic structure, consult a mason experienced in restoration.
How Joints Are Tooled
The tooling step is what gives each joint its shape and durability, and the timing matters. A mason waits until the mortar is “thumbprint hard,” firm enough to hold a shape but still workable, before running the jointing tool. Tool too early and the soft mortar smears; too late and the surface crumbles instead of compacting. The right moment, judged by experience, produces a dense, smooth joint surface that resists water far better than untooled mortar.
Each profile uses a specific tool. A concave joint uses a curved jointer or a length of pipe; a V-joint uses a V-shaped tool; a raked joint uses a skate-wheel raker set to a uniform depth. Quality tools and a steady hand are what separate crisp, professional joints from sloppy ones, which is part of why good masonry is a skilled trade rather than a casual DIY project.
Signs Your Joints Need Repointing
Mortar joints do not last forever, and on older walls they typically need attention before the bricks themselves do. Watch for crumbling or powdery mortar you can scratch out with a key, visible cracks running through the joints, gaps where mortar has fallen away, and any sign of moisture or efflorescence (white mineral staining) on the brick face. Left unaddressed, failing joints let water into the wall, which accelerates freeze-thaw damage and can eventually compromise the structure. Catching it early and repointing the affected sections is far cheaper than rebuilding a wall, and matching the original profile keeps the repair invisible.
Quick Selection Guide
- Wet or freezing climate, exterior: Concave, V-joint, or weathered.
- Best water shedding: Weathered joint.
- Dry climate or interior: Struck, raked, or flush.
- Rustic character: Extruded or weeping.
- Formal or historic detail: Beaded joint.
Final Takeaway
The different types of mortar joints are a balance between weather protection and appearance. For exterior walls in most US climates, a concave or V-joint gives you proven water resistance and a clean look, while a weathered joint is the top performer in harsh conditions. Save the raked, flush, and decorative profiles for interiors or dry regions where their good looks will not cost you in moisture damage. Match the profile and the mortar mix carefully on repairs, and your masonry will stand strong for decades.
