An external corner is the place that reveals the quality of a facade faster than anything else. On a flat surface, small mistakes may go unnoticed, but on a corner everything is visible: a crooked line, a “step,” uneven joint width, or careless cutting. The good news is that a straight corner is not magic — it is the result of several simple rules in marking, geometry, and installation technology.
Why a “Crooked Joint” Appears Exactly on the Corner
The typical reasons are almost always the same:
installation started without a clear vertical line, and the rows began to “drift”
the corner was not straight, but the cladding was installed along the crooked wall
cutting was done “as it turned out,” without symmetry
the joint on one wall did not match the rhythm on the other wall
the adhesive layer varied in thickness, and the planes did not meet evenly
1) Start with the Main Thing: the Corner Must Be Straight Before Finishing
Finishing does not correct a tilted corner — it highlights it. Before installation, check:
the verticality of the corner using a level or plumb line
depressions and protrusions
the strength and dryness of the substrate
If the corner “wanders,” it is better to locally level the corner area than to later fight the joints.
2) Marking Is Half of the “Premium Look”
To make the joint straight:
mark a vertical line along the corner
set the starting line of the row horizontally
work from the lines, not from “how it happens to lay”
Without marking, the facade almost always shifts into a wedge by the end of the wall.
3) Choose a Corner Strategy: Two Schemes That Work
Scheme A: Symmetry
The joints on both walls approach the corner equally, and the cuts look “mirrored.”
This is the most “premium” visual option.
Scheme B: Logical Joint Continuation
The joint “flows” around the corner in one line, as a continuation of the pattern.
This suits modern facades where clean geometry is important.
The main thing is to choose the scheme in advance. Random cutting makes the corner look cheap.
4) Cutting on the Corner: Avoid Thin Strips
The most common mistake is leaving a narrow 1–2 cm “noodle” strip on the corner. This:
looks bad
holds poorly
gets damaged faster
It is better to shift the layout so that the edge element has a proper width.
5) Adhesive Control and Layer Thickness — So There Is No “Step”
A “step” on the corner appears when:
the adhesive layer is thicker on one wall
thinner on the other
and the planes do not meet evenly
That is why it is important to maintain the same layer thickness and work on a level base. Preparation and priming are critical here.
6) If the Facade Is Installed Over Insulation, the Corner Must Be Reinforced
Corners on insulated facades are a risk zone. The following are important:
proper mesh with overlap
corner beads/profiles
no breaks in the reinforcing layer
That is why Facade Insulation must be done as a system; otherwise, cracks and “crookedness” appear first on the corners.
7) Why Practical “Stone-Look” Texture Is Often Used on Corners
A corner constantly receives impacts and touches, especially near the entrance. That is why both aesthetics and practicality matter. In such areas, KORDEKO Flexible Tile (PletaFlex) is often used — it allows clean corner lines and is convenient to process on detailed elements when the technology is followed.
Mini Checklist for Corner Inspection
the corner line is strictly vertical
the joints keep the same rhythm on both walls
there are no thin cuts directly on the edge
there is no “step” between the planes
on insulated facades, the corner is reinforced and there are no initial cracks