Why Joint Profile Matters
The mortar joint accounts for 15-20% of a masonry wall’s visible surface. The joint profile affects:
- Weather resistance: Some profiles shed water better
- Appearance: Dramatic impact on wall aesthetics
- Structural performance: Tooled joints compress mortar
- Historical accuracy: Matching existing work
Choosing the right profile isn’t just cosmetic—it impacts your wall’s longevity.
The Six Standard Joint Profiles
1. Concave Joint (Most Recommended)
Profile: Curved inward (half-round depression)
Made with: Round jointing tool, piece of pipe
Weather resistance: Excellent
Best for:
- Exterior walls
- All climates
- Most applications
Why it works: The tooling compresses mortar at the edges, creating a tight seal. The curved surface sheds water away from the joint.
Technique:
- Wait for mortar to become thumbprint hard
- Press jointing tool into joint
- Draw along joint with consistent pressure
- Tool vertical joints first, then horizontal
2. V-Joint
Profile: V-shaped groove in center
Made with: V-shaped jointing tool
Weather resistance: Very good
Best for:
- Exterior walls
- Traditional/historic appearance
- Alternative to concave
Why it works: Point of V creates shadow line while still compressing edges. Water runs to center and drains.
Technique:
- Press V-tool firmly into joint
- Maintain consistent angle
- Creates crisp shadow line
- More decorative than concave
3. Flush Joint
Profile: Flat, level with brick face
Made with: Trowel edge
Weather resistance: Fair
Best for:
- Interior walls
- Base for painting
- Some industrial applications
Limitations: Doesn’t compress mortar edges. Water can penetrate at brick-mortar interface.
Technique:
- Cut excess mortar flush with trowel
- Minimal tooling
- May be painted or parged
4. Raked Joint
Profile: Mortar recessed from brick face
Made with: Raking tool, bent nail
Weather resistance: Poor
Best for:
- Interior walls only
- Decorative effect
- Shadow lines
Caution: NOT recommended for exterior walls. The ledge collects water and accelerates deterioration. Freezing water can spall bricks.
Technique:
- Remove mortar to consistent depth (3/8” max)
- Clean debris from recess
- Creates dramatic shadow effect
5. Struck Joint
Profile: Angled inward from top to bottom
Made with: Trowel held at angle
Weather resistance: Poor
Best for:
- Interior applications
- Not recommended for exterior
Problem: The angle directs water toward the lower brick, encouraging saturation and damage.
6. Weathered Joint
Profile: Angled outward from top to bottom (opposite of struck)
Made with: Trowel held at angle, pressing inward at top
Weather resistance: Good
Best for:
- Exterior walls
- Alternative where tooling is difficult
- Quick production work
Why it works: Angle sheds water outward and down. Upper edge is compressed.
Specialty Joints
Beaded Joint
Profile: Raised half-round bead projecting from mortar
Use: Decorative, historical reproduction
Weather resistance: Fair (bead can deteriorate)
Grapevine Joint
Profile: Indented line down center of flush joint
Use: Colonial-era reproduction, decorative
Made with: Special grapevine jointer
Squeezed (Extruded) Joint
Profile: Mortar squeezed out and left natural
Use: Rustic appearance, intentionally rough
Weather resistance: Poor (not tooled)
Joint Profile Comparison
| Profile | Weather Resistance | Appearance | Difficulty | Best Use |
|---|---|---|---|---|
| Concave | Excellent | Clean | Easy | Exterior, any |
| V-Joint | Very Good | Decorative | Moderate | Exterior |
| Flush | Fair | Utilitarian | Easy | Interior |
| Raked | Poor | Bold shadows | Easy | Interior only |
| Struck | Poor | Angled | Easy | Interior only |
| Weathered | Good | Subtle | Moderate | Exterior |
Matching Existing Joints
For Repair Work
- Identify the existing profile by viewing at an angle
- Select matching jointing tool
- Practice on hidden area first
- Match mortar color (see below)
Common Profile Recognition
Concave: Smooth, curved depression
V: Sharp center line, angled sides
Flush: No visible profile, level with brick
Raked: Recessed shadow at joint
Tooling Timing
The Thumbprint Test
Ready to tool when:
- Press thumb into mortar
- Leaves clean impression
- Doesn’t stick to thumb
- Mortar holds shape
Too wet:
- Mortar smears
- Sticks to tool
- Won’t hold profile
Too hard:
- Tool tears mortar
- Black marks appear
- Surface crumbles
Typical Timing
| Conditions | Time After Laying |
|---|---|
| Hot/dry | 15-30 minutes |
| Moderate | 30-60 minutes |
| Cool/humid | 60-90 minutes |
Tooling Technique Tips
For Best Results
Tool vertically first:
- Prevents smearing on horizontal joints
- Clean tool frequently
Consistent pressure:
- Same compression throughout
- Creates uniform appearance
Work in sections:
- Tool as mortar reaches proper hardness
- Don’t wait until entire wall is laid
Keep tools clean:
- Build-up creates uneven profiles
- Wipe with wet rag frequently
Common Tooling Mistakes
| Mistake | Result | Fix |
|---|---|---|
| Tooling too early | Rough, torn surface | Wait longer |
| Tooling too late | Poor compression, cracking | Work in smaller sections |
| Inconsistent pressure | Wavy joint | Practice technique |
| Dirty tool | Uneven profile | Clean frequently |
Joint Color Matching
Factors Affecting Color
- Cement color: Gray vs. white cement
- Sand color: Major color contributor
- Pigments: Added for specific colors
- Water content: More water = lighter color
- Curing: Inconsistent curing causes color variation
Matching Existing Mortar
- Sample existing mortar (from hidden area)
- Analyze components (sand color, cement type)
- Make test batches with different ratios
- Cure samples fully (28 days) before comparing
- Wet samples when comparing (matches appearance better)
When to Hire a Professional
DIY-Appropriate
- New walls you’re building
- Hidden or non-critical repairs
- Interior applications
- Practice projects
Professional Recommended
- Historic restoration
- Visible exterior repairs
- Color matching critical
- Large repointing projects
Calculate Your Masonry Project
Planning a project that requires careful joint work? Use our Masonry Calculator to estimate materials including mortar needs.
Pro Tip: If you’re having trouble with timing, divide your wall into smaller sections. Lay and tool one section before starting the next. This ensures consistent tooling hardness throughout. For important walls, make a sample panel first to perfect your joint profile before the real work begins.