Masonry Joint Type Visual Guide

Visual comparison of mortar joint profiles with weather resistance ratings. Helps select the right joint style for repairs or new work.

Mortar Joint Types Comparison

Joint Type	Weather Resistance	Appearance	Best Use
Concave	Excellent	Rounded inward	Exterior walls - most common
V-Joint	Very Good	V-shaped groove	Exterior, decorative
Weathered	Excellent	Angled downward	Exterior, water shedding
Flush/Struck	Fair	Flat with surface	Interior, economy
Raked	Poor	Recessed, shadowed	Interior only, decorative
Beaded	Fair	Raised round bead	Decorative, sheltered areas

Concave Joint (Most Common)

Appearance: Curved inward, creating a rounded depression

Tool: Round jointer or convex jointing tool

Weather Resistance: ⭐⭐⭐⭐⭐ Excellent

Advantages:

Best water shedding properties
Compresses mortar against bricks
Creates strong seal
Industry standard for exterior work
Easy to create with proper tool

Disadvantages:

Requires specific jointing tool
More time-consuming than flush joint

✓ Recommended for all exterior masonry

V-Joint

Appearance: V-shaped groove pointing outward

Tool: V-shaped jointer

Weather Resistance: ⭐⭐⭐⭐ Very Good

Advantages:

Good water drainage
Attractive shadow lines
Suitable for exterior use
Compresses mortar

Disadvantages:

More difficult to tool than concave
Sharp edges can chip over time
Requires steady hand for uniform appearance

✓ Good for exterior decorative work

Weathered Joint

Appearance: Angled downward from top to bottom brick

Tool: Trowel

Weather Resistance: ⭐⭐⭐⭐⭐ Excellent

Advantages:

Excellent water shedding - water runs off easily
Can be formed with trowel edge
Traditional appearance
Very durable in harsh weather

Disadvantages:

Difficult to achieve uniform angle
Requires skill and practice
Not as commonly seen (less familiar)

✓ Best choice for extremely wet climates

Flush/Struck Joint

Appearance: Mortar flush with brick face

Tool: Trowel edge

Weather Resistance: ⭐⭐⭐ Fair

Advantages:

Fastest and easiest to create
No special tools required
Economical for large projects
Adequate for interior walls

Disadvantages:

Poor water resistance
Mortar not compressed
Can allow water infiltration
Less durable long-term

⚠ OK for interior, avoid for exterior in wet climates

Raked Joint (Not for Exterior!)

Appearance: Mortar recessed 1/4" to 1/2" behind brick face

Tool: Raking tool or square tool

Weather Resistance: ⭐ Poor

Advantages:

Very attractive - creates deep shadow lines
Emphasizes individual brick texture
Popular in historic/decorative interior work

Disadvantages (Critical for Exterior):

❌ Ledge collects water
❌ Water sits against brick edge
❌ Freeze-thaw damage likely
❌ Mortar exposed to weather on edges
❌ Poor durability outdoors

⚠️ NEVER use raked joints on exterior walls in climates with freeze-thaw cycles or heavy rain!

✓ OK for interior decorative walls only

Beaded Joint

Appearance: Raised convex bead protruding from brick face

Tool: Special beading tool

Weather Resistance: ⭐⭐ Poor-Fair

Advantages:

Highly decorative
Unique appearance
Traditional/historic look

Disadvantages:

Protruding mortar exposed to weather
Can trap water on top
Not suitable for harsh climates
Requires specialized tool

⚠ Use only in sheltered locations or interior

Jointing Technique & Timing

Proper Timing (Critical):

Tool when "thumbprint hard": Mortar should hold a thumbprint without sticking
Too early: Mortar smears and stains bricks
Too late: Mortar too hard, won't compress properly
Window: Usually 30-60 minutes after laying brick (varies by weather)

Technique:

Tool horizontal joints first (long runs)
Then tool vertical joints (head joints)
Use consistent pressure throughout
Tool in one smooth motion when possible
Remove excess mortar with trowel
Brush lightly after mortar sets (don't smear)

Weather & Climate Considerations

Freeze-Thaw Climates (Northern regions)

Best Choices: Concave, V-Joint, Weathered

Avoid: Raked, Beaded, Flush (exterior)

Why: Water must shed quickly - any standing water in joints freezes and causes spalling

Wet Climates (High rainfall)

Best Choices: Concave, Weathered

Avoid: Raked, Flush

Why: Excellent water shedding essential to prevent moisture infiltration

Dry/Mild Climates

More Options: Most joint types acceptable

Still Recommended: Concave for best longevity

Avoid Exterior: Raked (even in dry climates, morning dew can cause issues)

Common Jointing Mistakes

❌ Using raked joints on exterior walls:

Guaranteed water damage and deterioration

❌ Tooling too early:

Smears mortar on brick face, creates stains

❌ Tooling too late:

Doesn't compress mortar, poor weather seal

❌ Inconsistent joint depth:

Unprofessional appearance, uneven water shedding

❌ Not removing mortar droppings:

Dried mortar on brick face very hard to remove

Repointing Old Mortar Joints

When to Repoint:

Mortar crumbling or falling out
Gaps deeper than 1/4"
Water infiltration through joints
Historic building maintenance

Match Original Joint Type:

For historic buildings, replicate original joint profile
Match depth and finish
Use compatible mortar type (Type O for old/soft brick)

Process:

Remove old mortar to depth of 2-3x joint width (min 1/2")
Clean joint thoroughly
Dampen joint (don't saturate)
Pack new mortar firmly
Tool to match existing joints

Quick Reference - Best Joint by Application

✓ Exterior Walls (Most Common): Concave Joint

✓ Extreme Weather: Weathered or Concave

✓ Decorative Exterior: V-Joint or Concave

✓ Interior Walls: Flush, Concave, or Raked

✓ Interior Decorative: Raked or Beaded

✓ Budget/Speed: Flush (interior only)

When in doubt: Use Concave Joint - works well in all applications

Additional Information

About This Masonry Joint Type Guide

The mortar joint profile you choose dramatically affects both the appearance and weather resistance of brick, block, and stone masonry. While raked joints create beautiful shadow lines, using them on exterior walls in wet or freezing climates will lead to rapid deterioration and water infiltration. Understanding which joint types shed water and which trap it is essential for durable masonry work.

This guide compares the most common mortar joint profiles - concave, V-joint, weathered, flush, raked, and beaded - with their weather resistance ratings, proper applications, and tooling techniques. You'll learn why concave joints are the industry standard for exteriors and when decorative joints like raked profiles can be safely used.

Whether you're building a new brick wall, repointing historic masonry, or simply trying to understand why your exterior mortar is failing, this reference provides the knowledge to select and create appropriate joint profiles for your climate and application.

Why Use This Reference Guide?

Choosing the wrong mortar joint profile can lead to water damage, freeze-thaw spalling, and premature mortar failure. This guide helps you make informed decisions that will last for decades.

Compare weather resistance of different joint profiles
Select appropriate joints for your climate and exposure
Learn proper tooling timing and technique
Understand why certain joints fail in exterior applications
Match joint profiles for repointing and repairs
Know which tools create each profile type

Frequently Asked Questions

What is the best mortar joint for exterior brick?

The concave joint is the best choice for most exterior applications. Its curved profile sheds water effectively, and the tooling process compresses the mortar against the brick edges, creating a tight seal. V-joints and weathered joints are also acceptable for exteriors. Never use raked joints on exterior walls - the recessed ledge collects water that causes freeze-thaw damage and mortar deterioration.

When should I tool mortar joints?

Tool joints when the mortar is "thumbprint hard" - firm enough to hold an impression without mortar sticking to your thumb. This is typically 30-60 minutes after laying brick, but varies with temperature and humidity. Tooling too early smears mortar on brick faces; too late and the mortar won't compress properly. Tool horizontal (bed) joints first, then vertical (head) joints.

Can I use raked joints on interior masonry?

Yes, raked joints are appropriate for interior walls where they won't be exposed to water. The deep shadows create an attractive, textured appearance that emphasizes individual bricks. Rake joints 1/4" to 1/2" deep using a raking tool or square jointer. They're popular for decorative interior feature walls, fireplaces (not the firebox), and sheltered exterior areas that never get wet.

How do I match existing mortar joints for repairs?

For repointing, match both the joint profile and mortar color/composition. Identify the original joint type by examining the cross-section, then use the same tooling technique. For historic buildings, also match mortar hardness - old buildings used soft lime mortar that shouldn't be replaced with hard Portland cement mortar, which can damage soft historic brick. Take a sample to a masonry supplier for color matching.

Why is my mortar cracking and falling out?

Common causes include: wrong joint profile for the exposure (raked joints in wet areas), mortar not properly compressed during tooling, incorrect mortar mix, or mortar that's too hard for soft brick. In freeze-thaw climates, trapped water expands and breaks down the mortar. Solutions include repointing with proper joint profiles, using correct mortar type for conditions, and ensuring joints are tooled at the right time.

What tools do I need for jointing masonry?

Essential tools include: convex jointer (sled runner) for concave joints, V-jointer for V-joints, flat trowel edge for weathered and flush joints, raking tool for raked joints, and a stiff brush for cleanup. Match tool width to your joint width. A jointer set typically includes multiple sizes. Quality tools create consistent profiles - cheap tools can mar the finish. Clean tools frequently during use.

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