Brise Soleil: A Complete Guide to Façade Sun-Shading Systems.

Brise soleil (French for "sun breaker") is an architectural sun-shading system mounted on a building's façade — usually horizontal or vertical aluminium louvres positioned in front of glazing to control solar gain, glare and overheating. One of the oldest and most effective passive cooling techniques in modern architecture, popularised by Le Corbusier in the 1930s and now standard on energy-conscious commercial buildings.

What is brise soleil?

A sun-shading device — an array of louvre blades, fins or panels — mounted on the exterior of a building, almost always covering glass façades. Blades are angled and spaced so direct sunlight is blocked during peak hours but daylight and views are preserved.

Configurations: fixed (static), adjustable (rotating or sliding louvres), sliding panel (full panels moving on rails).

What are the pros and cons of fixed vs adjustable brise soleil?

The single most-asked question by specifiers. Honest answer: fixed wins on cost and durability, adjustable wins on year-round performance.

Fixed brise soleil

Pros: no moving parts → 25–50 year service life with zero mechanical maintenance; lower initial cost; simpler structural calculation; architectural rhythm; no power required.

Cons: compromise angle (worst-case sun position dominates design — winter sun also blocked); no tuning post-install; daylight reduction 25–40% year-round.

Adjustable (sliding or rotating)

Pros: year-round optimisation (open in winter for solar gain, closed in summer); user/BMS control; higher LEED/DGNB credit; better daylight harvesting.

Cons: 1.5–2× the cost; mechanical maintenance every 5–10 years; power infrastructure; complex structural calculation (dynamic load cases).

When to choose which

- Office or hospitality, south-west façade → adjustable. Solar gain dominates cooling load. 5–8 year energy payback. - Residential, north or east → fixed. Sun exposure limited; complexity not justified. - Heritage retrofit → fixed (planning constraints). - Budget-constrained, single orientation → fixed.

What are the structural requirements for brise soleil?

Governing standards: EN 1991 (actions on structures) and EN 1090-3 (execution of aluminium constructions).

Wind load (EN 1991-1-4)

1. Determine basic wind speed for project location (national annex). 2. Calculate exposure category by building height + terrain. 3. Apply force coefficients for louvre arrays (Cf = 1.6–2.4 depending on blade spacing and angle). 4. Verify panel AND fixing — most failures are bracket-to-substrate, not the louvre.

For a typical 3m × 1.5m fixed louvre panel in central Europe: 0.8–1.6 kN/m² ultimate design pressure. Always require a project-specific structural report from the supplier — not a generic certificate.

Self-weight

Aluminium 6063-T5 louvres: 0.4–1.2 kg/m. Complete panel including frame and fixings: 8–25 kg/m² of substrate load.

Differential thermal expansion

Aluminium expands 0.024 mm/m/°C. A 6m panel moves 5–7mm seasonally. Mounting brackets must accommodate this with sliding fixings on at least one end — otherwise stress accumulates and brackets fail by fatigue.

Fixing to substrate

The most-overlooked failure mode: - Concrete: mechanical anchors per ETA approval. - Masonry: bonded chemical anchors, never plug-and-screw. - Steel: welded brackets or bolted with structural calculation. - Cavity wall / ETICS: through-bolted to inner leaf with thermal-break sleeves.

Always require a fixing pull-out test on the actual substrate before completing high-rise installations.

Material choices

Aluminium (the standard)

6063-T5 — tensile strength 185 MPa, 0% water absorption, QUALICOAT Class 2 powder coat for 15+ year UV stability, recyclable end-of-life. Profile shapes: elliptical, rectangular, Z-profile, C-profile.

Wood

Less common — heavier, more maintenance, fire risk. Western Red Cedar or thermally modified hardwood occasionally used in low-rise residential.

Steel

Heavy duty industrial only — galvanised + powder-coated.

WPC

Generally unsuitable — thermal expansion 8–15mm/m vs aluminium's 0.024mm/m/°C. WPC fins visibly bow under summer sun.

Design parameters

D/S ratio (blade depth / spacing) governs shading geometry: - 0.3–0.5: light shading, north or partially shaded façades - 0.7–1.0: moderate shading, most common spec - 1.2–1.5: heavy shading, unfavourable orientations only

Mounting distance from façade: 100mm minimum for ventilation and cleaning access; 200–300mm typical.

Specification checklist

- [ ] EN 1991 structural calculation report — project-specific - [ ] QUALICOAT Class 2 powder coat warranty (15+ year colour retention) - [ ] CE marking with declaration of performance - [ ] EN 13501-1 fire classification (A1 or A2 for projects within 3m of openings) - [ ] Substrate fixing strategy with pull-out test data - [ ] Mounting tolerance ±5mm on all axes - [ ] Single-blade replacement availability at 10/15/25 years - [ ] Maintenance schedule with access strategy

How long does brise soleil last?

Correctly specified aluminium brise soleil with QUALICOAT Class 2 finish: 25–35 years with minimal intervention. Colour finish is the limiting factor — gloss reduction at year 15–20. Re-coating in situ possible, or panels removed for refinishing.

Mechanical components on adjustable systems: 10–15 year service life, designed for replacement without removing panels.

Common failures (and how to avoid them)

1. Fixing pull-out — undersized anchors or poor substrate. Mitigation: pull-out test before completion. 2. Blade rattle in wind — insufficient stiffness. Mitigation: verify natural frequency above 8 Hz. 3. Galvanic corrosion at steel-aluminium interface. Mitigation: stainless or zinc-coated bolts with EPDM washers. 4. Coating chalking on south façade. Mitigation: insist on QUALICOAT Class 2 with documented test certificates. 5. Differential thermal stress cracking. Mitigation: sliding brackets at one end of each panel.

Brise soleil systems by PONARC

PONARC supplies three brise soleil configurations across Europe: - [Fixed brise soleil](/en/products/brise-soleil/fixed) — static aluminium louvres, multiple profile shapes. - [Sliding brise soleil](/en/products/brise-soleil/sliding) — louvre panels on façade rails, manual or motorised. - [Folding brise soleil](/en/products/brise-soleil/folding) — hinged panels swinging flat against the façade.

Each ships with EN 1991 structural calculation report and CE marking.

Conclusion

Brise soleil is one of the most cost-effective passive cooling strategies in modern construction. Whether to specify fixed or adjustable depends on orientation, programmatic flexibility, and budget — but in both cases, structural and finish specification is what separates a 30-year installation from a 10-year disappointment.

For specifiers, the single most important requirement is a project-specific EN 1991 calculation report — generic certificates aren't enough for façade-mounted installations.