Mortar joint (profile)
Mortar joint profile (struck, raked, weather-struck, ironed) affects weather performance and appearance. AS 3700 sets 10 mm nominal joint width and finish rules.
Ask Chalkline about this →A mortar joint is the cement-and-sand mortar filling between adjacent bricks or blocks. The two orientations are the bed joint (horizontal, under each course) and the perpend (vertical, between bricks within a course). Standard residential nominal joint width is 10 mm for both. The third element, the profile (the shape of the visible mortar surface), is what this entry covers.
Why profile matters. The profile controls two outcomes:
- Weather performance: how water shedding works at the joint. Joints that face up or back into the wall (e.g. raked) catch and hold water; joints that face down or out (e.g. weather-struck) shed water away.
- Appearance: the look of the finished wall. Different profiles produce different shadow lines and visual rhythms.
The common residential profiles:
| Profile | Description | Where used |
|---|---|---|
| Struck (or weather-struck) | Mortar struck flush then tooled at a downward angle, the bottom edge proud of the top edge. Sheds water. | Standard residential face brickwork. The volume default. |
| Ironed (or concave) | Mortar tooled to a smooth concave curve with a jointer or hose. Compacts the surface, sheds water well. | Premium residential and commercial face work. |
| Flush | Mortar struck off level with the brick face, no tooling. Simple but holds water in the joint. | Internal walls; render substrates. |
| Raked | Mortar raked back 5 to 12 mm from the brick face after initial set. Strong shadow line. | Architectural feature walls. Aesthetics-driven. |
| Bucket-handle | Concave profile pressed with a bucket-handle tool. Variant of ironed. | Common alternative to ironed. |
| V-joint | Mortar pressed into a sharp V channel. Strong shadow, sheds water. | Heritage and feature. |
| Beaded | Decorative profile with a small bead in the joint. Heritage. | Conservation work, period reproduction. |
Raked joints have a weather penalty. A raked joint in exposed exterior brickwork lets water sit at the back of the rake, eventually wicking into the bed mortar and the brick face. AS 3700 and the state Guides to Standards and Tolerances accept raked joints architecturally but specify additional protection (e.g. eaves overhangs at >450 mm) on exposed elevations.
Tooling timing. All profiles except flush and raked must be tooled at the thumb-print stage: the mortar firm enough to hold the profile but soft enough to tool without cracking. Tooling too early closes the joint with mortar slurry; too late produces a torn or chipped surface. The window is typically 30 minutes to 2 hours after laying, depending on weather.
Joint colour. The mortar mix sets the joint colour, which can be:
- Natural (grey): standard cement-and-sand mortar.
- Coloured: cement-and-sand-and-oxide for tinted joints (red, brown, black, white).
- White: white cement with white sand for premium and contrast applications.
Once a joint is laid, the colour cannot be changed without raking back to 10-15 mm depth and repointing.
Common defects:
- Sloppy profile: inconsistent tooling, scuffed corners, visible variation course-to-course.
- Reversed weather-struck (tooled with top edge proud, water-catching): often a left-hand vs right-hand brickie issue. Rectification is rake-out and repoint.
- Open perpends: missing or partial mortar in vertical joints. Water entry path. A discovered open perpend is a defect at PCI.
For builders.
- Specify the profile at design stage. Don’t leave it to the brickie’s preference.
- Confirm the mortar colour against a sample wall before the brickie lays beyond a couple of courses.
- Inspect profile consistency across the wall during build, not at PCI.
Also known as: pointing, joint profile, joint finish.
Category: Practical / masonry / finishes.
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Last updated: 2026-05-14. Verified: 2026-05-14.