An outside corner concentrates several facade decisions into one narrow zone: panel module, exposed edges, support rails, tolerances, open joints, water paths and the desired visual line. Three established approaches are miter-cut panels, a metal corner flashing, and a purpose-made terracotta corner. None is automatically best; the right method depends on geometry, panel section, quantity, programme and the complete rainscreen detail.
Start with the real corner geometry
A drawing marked “90°” is not enough. Survey the supporting structure and define the visible corner line, cavity, insulation, membranes, rails and bracket clearances. Check whether the two facade modules arrive at the corner with equal panel widths or whether one elevation should pass the other. Movement and construction tolerances need room without leaving an irregular gap.
The corner should also be reviewed from normal approach routes. A narrow metal line may disappear from one angle and become prominent from another. A special-shaped clay piece may create the most continuous appearance but can make replacement or setting-out more demanding. Full-size details reveal these differences more clearly than a small elevation rendering.
Internal corners need similar discipline even though their visual and weather exposure differ. Allow the adjoining walls to move without pinching panels, keep the drainage plane continuous and confirm how installers reach clips or fasteners. This article concentrates on outside corners, but the same module and tolerance study should cover every return in the facade package.
Method 1: miter-cut terracotta panels
For a conventional right-angle corner, two panel edges may be cut at approximately 45° and brought together to form a 90° return. Other building angles require different cuts. The old page described factory cutting as a widely used and cost-effective method, but suitability depends on the panel section, remaining edge strength, equipment, tolerance and shipping risk.
A miter can create a crisp clay-to-clay line with little visual interruption. The cut may also expose a hollow body or create a fragile arris, so the manufacturer should approve the cutting location and minimum remaining material. The installer must not force two brittle edges together; provide the specified clearance and a consistent shadow or sealed joint.
The archived method mentioned inserting a rubber strip for water diversion. That is one historical detail, not a universal solution. Water management must be coordinated through the joint, cavity, membrane and flashings of the actual system. Any gasket or strip needs compatible material, secure retention and a defined drainage route.
Method 2: aluminium or stainless-steel flashing
A formed metal profile can cover or articulate the corner while accommodating the edges of standard panels. Aluminium alloy and stainless steel were both mentioned in the original article. Material grade, thickness, fixings and finish should be selected for structural demand, corrosion environment and compatibility with neighbouring metals.
The flashing may match the terracotta for a quiet transition or use a contrasting colour to make the corner a deliberate vertical line. A fluorocarbon or other coating should be specified by an exact system and colour rather than a generic description. Detail laps, end conditions and drainage so the trim does not trap water or rely on face sealant alone.
Method 3: purpose-made terracotta corner
A special extrusion can wrap the corner in the same clay material as the main elevation. Archived examples included curved, triangular and L-shaped right-angle pieces, as well as supplementary baguette or louver profiles. This approach can produce strong material continuity and avoid a visible metal trim.
Custom corners require early coordination. The section must be extrudable, dry and fire without unacceptable distortion, connect to the support system and match adjacent panels within the approved colour range. Tooling, minimum production quantity, achievable length, handed pieces and replacement stock affect cost and schedule. The old page called special shapes more expensive; the real comparison requires a current quotation including factory cutting, trims, site labour and risk.
Compare the three methods by project priorities
| Method | Visual result | Key checks |
|---|---|---|
| Miter-cut panels | Fine clay-to-clay corner with minimal added material | Edge strength, cut accuracy, hollow-body exposure, joint clearance, packing and water path |
| Metal flashing | Matching or contrasting vertical line | Grade, coating, corrosion compatibility, fixings, laps, movement and drainage |
| Special terracotta shape | Continuous clay material and sculpted return | Tooling, extrusion limits, firing tolerance, support, handed units, MOQ and spares |
The legacy ranking—miter as most common and cost-effective, metal as convenient, special shapes as harmonious but costly—should be treated as a 2016 generalisation. Geometry, labour rates, quantity, panel body and design intent can reverse those conclusions on a specific project.
Detail, mock up and inspect the corner
Before production
Issue plan, elevation and full-size sections showing panel codes, joint widths, supports, membranes, trim and drainage.
During mock-up
Check appearance from both elevations, edge quality, colour match, installation access and how water leaves the assembly.
During installation
Survey rails, maintain clearances, protect exposed arrises and reject forced or visibly damaged corner pieces.
At handover
Record product codes and retain suitable spare panels, trims, gaskets or special shapes for future replacement.
Explore terracotta rainscreen panels, review terracotta baguettes and louvers, and compare completed elevations in the project gallery.