A terracotta louver becomes useful solar control only when its geometry, supporting frame and glazing are designed as one assembly. Profile selection alone cannot establish comfort or energy performance. A reliable specification starts with the sun path and occupied spaces, then translates the analysis into measurable dimensions, loads, tolerances, finishes, tests and installation responsibilities.
Define the design outcome before choosing a profile
Begin with the problem the screen must solve. Is the priority reducing direct sun at workstations, limiting summer solar gain, maintaining outward views, filtering daylight, creating privacy, or giving the elevation depth? Rank these outcomes for each facade rather than applying one louver arrangement around the building.
Record climate file, latitude, true orientation, neighbouring obstructions, glazing properties, room use and occupied hours. East and west elevations receive low-angle sun and usually need a different response from a facade dominated by high solar altitude. Fixed louvers also create permanent shade, so winter access to useful sun and daylight must be considered alongside the cooling-season objective.
The original article, published on 16 December 2015, described reduced overheating, glare control and improved daylight as general benefits. Treat those statements as an archive design rationale, not a project guarantee. Current energy, daylight and glare models must confirm the result for the actual louver-and-glazing combination.
Model the louver and glazing together
Test profile depth, spacing, rotation, offset from glass and horizontal or vertical orientation against representative dates and hours. Include the exact glass solar and visible-light properties; a louver cannot be evaluated independently of the window behind it. The analysis should identify direct-sun hours, useful daylight, glare risk, solar gain and view obstruction at critical occupied positions.
Compare a small number of buildable options rather than optimizing an abstract screen that cannot be manufactured or supported. The calculation method, assumptions and acceptance criteria belong in the design record. ISO 52022-1 is one current reference for estimating solar and light characteristics of solar protection devices combined with glazing; the project team must confirm the applicable local method and current edition.
Turn geometry into a coordinated product schedule
| Schedule item | What to state | Why it matters |
|---|---|---|
| Terracotta unit | Profile code or approved custom section, length, depth, width, wall arrangement, end condition, colour and surface | Controls appearance, weight, span and replacement |
| Layout | Orientation, centre spacing, rotation angle, offset, joint and termination dimensions | Connects the model to the elevation |
| Support | Carrier type, brackets, pins or rods, retainers, isolators, fasteners and substrates | Defines the complete load path |
| Tolerance | Unit, frame, substrate and cumulative setting-out limits | Prevents forced installation and drifting lines |
Ask the manufacturer to identify maximum practical length, allowed support locations, cutting restrictions and minimum quantities for any custom extrusion. Approve colour as a range using physical samples; fired clay should not be specified as though every unit will be visually identical.
Engineer loads, movement and safe retention
Terracotta elements and their metalwork must resist project-specific wind pressure and suction, self-weight, seismic demand where relevant, maintenance loads and foreseeable impact. Calculate local corner and edge zones, not only field-of-wall pressure. Trace each action through the clay unit, internal pin or carrier, bracket, rail, fastener and primary substrate.
Coordinate differential movement between terracotta, metal framing and the building structure. Slots, sliding connections or clearances may be needed, but they must not compromise retention. Define end restraint so a cracked element cannot migrate or fall. Also review galvanic compatibility, corrosion environment, drainage at horizontal members and interfaces with the curtain wall, waterproofing, fire barriers and lightning-protection strategy.
Design access, edges and visual continuity
A screen that performs in simulation can still create operational problems. Check window-cleaning routes, facade-access equipment, opening vents, signage, lights, cameras, bird activity and replacement access. Avoid ledges that hold debris or water, and detail open ends where insects or nesting are a project concern without blocking drainage or thermal movement.
Resolve corners, parapets, soffits and the first and last bay at full scale. Align supports with the architectural rhythm and keep conspicuous fasteners consistent. A coordinated elevation should label repeated types and exceptional pieces so pricing, fabrication and installation teams are working from the same set of information.
Specify evidence and project testing
Product evidence
Request current dimensions, mass, tolerances, finish limits, material data and test reports relevant to the supplied profile. Confirm that reports cover the proposed section and support condition.
Structural verification
Require calculations and connection data for project loads, substrates and exposure. Define the responsible engineer and any delegated-design boundaries.
Visual mock-up
Review colour range, joint rhythm, support visibility, ends, corners and the view from inside before releasing full production.
Performance mock-up
Where risk justifies it, test the representative assembly for specified wind, movement, impact or other project criteria using an agreed protocol.
Do not carry legacy performance, environmental, certification or market figures into the specification. Any such claim from the 2015 archive requires confirmation in current, product-specific documents issued for the project.
Issue an enquiry that manufacturers can price
A useful enquiry includes elevations and sections, a louver schedule, quantities by type, design pressures, substrate zones, finish intent, sample and mock-up requirements, test criteria, delivery sequence and required spare units. State whether the supplier is pricing terracotta only, a coordinated support kit or engineering for the complete sunscreen. This removes major assumptions before bids are compared.
Review terracotta baguette and louver options, see built applications in the terracotta sunscreen gallery, and coordinate adjacent opaque areas with the terracotta rainscreen system.