Horizontal louvres
Blades running across the façade. Best on equator-facing elevations, where the sun is high at midday and a horizontal shade blocks it while leaving the view open.
Solar shading
Aluminium Sunshade Systems
An aluminium sunshade system blocks direct sun before it reaches the glass: fixed or adjustable louvres, brise soleil fins, awnings over windows and doors, entrance canopies and perforated façade screens. Shading on the outside of a building stops far more heat than blinds inside it, cutting cooling loads and glare while keeping daylight and views. Metline supplies the extrusions, sheet, perforated panels and brackets for shading systems, cut, finished and machined to drawing, to projects worldwide.
- Blades & frames
- 6063-T5/T6, 6060, 6005A
- Panels
- 3003, 3105, 5005 sheet
- Forms
- Louvres, fins, awnings, canopies
- Finish
- Powder, PVDF, anodised, wood-grain
Why external aluminium sunshades work
Sunlight that passes through glass turns into heat inside the room, and most of that heat stays there. An internal blind absorbs it after it is already indoors. An external sunshade intercepts the radiation outside the glass, where the heat it absorbs is carried away by the air. That is why architects treat external shading as one of the most effective passive measures for cooling, especially on east, west and equator-facing façades.
Aluminium is the default material for this job. It is light, so long louvre blades and deep canopies place little load on the façade. It extrudes into airfoil, Z, C and rectangular blades with screw ports and clip grooves in the section. It does not rust when cut or drilled, and a powder, PVDF or anodised finish keeps its colour in strong UV for decades. At the end of the building's life it is recycled without loss of quality.
A good shading design balances three things: blocking high summer sun, admitting low winter sun and daylight where heating is needed, and keeping views out of the window. The geometry of the blades, not the material alone, decides how well a system does this, so the first step is always to look at orientation, latitude and the sun path for the site.
Types of aluminium sunshade systems
Vertical fins
Upright blades that block low-angle morning and evening sun on east and west façades. Often rotated to an angle to suit the sun path.
Brise soleil
A projecting array of louvres on brackets fixed to the frame or structure, forming a shading shelf above or in front of glazing.
Adjustable (operable) louvres
Blades that rotate manually or with motors and sun sensors, so shading can follow the sun and open fully on dull days.
Window and door awnings
Fixed aluminium hoods over windows, doors and porches that shade the glass and keep rain off; flat-panel or louvred.
Entrance and walkway canopies
Cantilevered or post-supported roofs over entrances, drop-off points and walkways, with integrated gutters.
Perforated façade screens
Perforated or expanded aluminium panels forming a second skin; they filter light, add privacy and can carry patterns or images.
Sliding and folding shutters
Framed louvre or perforated panels that slide or fold in front of windows and balconies, giving occupants control.
Patio covers
Free-standing or wall-mounted louvred roofs for terraces; see our pergola pages for systems with rotating roof blades.
Choosing the right shade for each façade
The sun's position changes with orientation, season and latitude, so a single shading type rarely suits a whole building. The guide below is for the northern hemisphere; swap north and south for the southern hemisphere. Near the equator the sun is high for most of the day and horizontal shading does most of the work.
| Façade | Sun behaviour | Most effective shading |
|---|---|---|
| South (north in the southern hemisphere) | High sun at midday, especially in summer | Horizontal louvres, brise soleil, deep overhangs |
| East | Low sun in the morning | Vertical fins, adjustable louvres, perforated screens |
| West | Low, hot sun in the afternoon; the hardest to control | Vertical or angled fins, operable louvres, screens |
| North (south in the southern hemisphere) | Little direct sun; mostly diffuse light | Often none, or light fins for glare at dawn and dusk in summer |
| Roofs and skylights | High sun most of the day | Fixed or rotating roof louvres, perforated panels |
Blade spacing and depth together set the cut-off angle: the sun altitude above which no direct sun reaches the glass. As a simple rule, horizontal blades spaced at a distance equal to their depth give a cut-off of about 45°; closer spacing or deeper blades raise the protection but reduce the view. Blade angle, spacing and projection should be checked with a sun-path study or shading software for the site latitude.
Shading performance is usually reported as the total solar energy transmittance gtot of glazing plus shade, calculated to EN ISO 52022 (which replaced EN 13363) and classified to EN 14501. Lower gtot means less heat entering the building.
Louvre blade shapes and how to size them
| Blade type | Typical widths | Characteristics | Typical use |
|---|---|---|---|
| Airfoil (aerofoil) | 100 – 600 mm | Hollow, aerodynamic section; stiff over long spans and quiet in wind | Brise soleil, large façade louvres, operable systems |
| Rectangular / box blade | 50 – 400 mm deep | Strong closed section with a modern look; can be vertical or horizontal | Vertical fins, screens, feature façades |
| Z and S blades | 50 – 150 mm | Overlapping shapes that block sight lines and rain while passing air | Plant screens, ventilation louvres, privacy screens |
| C and flat blades | 25 – 150 mm | Light, economical sections for short spans | Window awnings, small screens, fences |
| Elliptical blades | 100 – 400 mm | Smooth oval shape, similar stiffness to airfoils | Architectural brise soleil |
| Perforated panel | Sheet 2 – 4 mm | Open area typically 20 – 50 %; filters rather than blocks light | Façade screens, balcony panels |
The governing loads are wind and the blade's own weight. Wind pressure on a projecting brise soleil or vertical fin can be high at corners and on tall buildings, and long blades must also resist vortex-induced vibration, which produces noise and fatigue at the fixings. Designers check bending stress, deflection (often limited to around span/175 to span/250 for visual reasons) and fixing pull-out using local wind codes such as EN 1991-1-4 or ASCE 7 and aluminium design codes such as EN 1999 or the Aluminum Design Manual.
In practice, most louvre spans between supports are in the range of about 1.5 to 3 m. Longer spans call for deeper airfoil sections, internal stiffeners or intermediate supports. Thermal expansion also matters: a 3 m aluminium blade grows by about 2 mm for a 30 °C temperature rise, so end connections need slotted holes or sliding fixings.
Which aluminium alloy for each shading component?
Shading systems combine extrusions for the structure and blades with sheet for panels, hoods and perforated screens. Each component suits a different alloy.
| Alloy | Product form | Strengths | Use in shading systems |
|---|---|---|---|
| 6063-T5 / T6 | Extrusion | Excellent extrudability and surface finish; good strength after ageing | Louvre blades, frames, mullions, support arms, edge trims |
| 6060-T5 / T66 | Extrusion | Similar to 6063, very fine surface; popular in Europe | Thin-wall blades and decorative profiles |
| 6005A-T6 / 6061-T6 | Extrusion, plate | Higher strength for structural parts | Outriggers, brackets, long-span carrier beams |
| 3003-H14 / H24 | Sheet, coil | Formable, moderate strength, good corrosion resistance | Awning panels, canopy soffits, perforated screens, folded hoods |
| 3105 coated coil | Pre-painted coil | Economical substrate for roll-formed and coil-coated parts | Roll-formed blades, roofing for canopies |
| 5005-H14 / H24 | Sheet | Anodises with consistent colour; slightly stronger than 3003 | Anodised façade panels and blades with high appearance demands |
| 5052-H32 | Sheet | Higher strength, very good in coastal air | Marine and coastal panels, thicker perforated screens |
| 1100 / 1050 | Sheet | Very formable, low strength | Light decorative trims only; not for load-bearing parts |
A short selection rule: use 6063 or 6060 for anything extruded, 6005A or 6061 where a part carries significant load, 5005 for anodised panels, 3003 or 3105 for painted panels and canopies, and 5052 near the sea. Stainless steel fasteners are standard; isolate them from the aluminium with nylon or EPDM washers to limit galvanic corrosion, especially in coastal air.
Aluminium awnings and canopies
Awnings and canopies shade doors and windows and keep rain off entrances. Unlike fabric awnings, aluminium versions do not fade, sag or tear, and they can be left out in all weather.
| Type | Construction | Where it is used |
|---|---|---|
| Window awning | Flat panel, louvred or curved hood on side brackets | Homes, offices, shops, mobile homes |
| Door / entrance canopy | Cantilevered aluminium roof with fascia and concealed gutter | Front doors, storefronts, office entrances |
| Walkway canopy | Posts and beams with a flat, pitched or curved roof deck | Schools, hospitals, car parks, campuses |
| Patio or porch awning | Wall-mounted frame with insulated or ribbed aluminium roof panels | Terraces, decks, porches |
| Retractable awning | Aluminium cassette and arms carrying a fabric cover | Restaurants, patios where shade is needed only part of the day |
| Prefabricated canopy kit | Factory-cut frame, panels and fixings for fast site assembly | Repeat entrances on large projects |
Cantilever canopies place a large bending moment on the wall connection, so the fixing design and the strength of the supporting wall need checking, often with tie rods back to the façade. Every canopy roof should fall towards a gutter or drip edge so water does not run back onto the wall or drip onto people entering the building.
Surface finishes for exterior shading
Shading components face full sun and rain on every surface, so the finish is part of the performance specification, not just the colour.
Powder coating
Polyester powder in any RAL colour, matt to gloss. Specify AAMA 2604 or Qualicoat Class 2 for most façades, and AAMA 2605 or Qualicoat Class 3 for high-UV or prestige projects.
PVDF (fluorocarbon)
Two- or three-coat liquid fluoropolymer paint with excellent gloss and colour retention, the usual choice for tall façades and coastal sites; meets AAMA 2605.
Anodising
A hard, metallic finish grown from the aluminium. Use at least 20 – 25 µm film (Qualanod Class 20 or 25) outdoors; 5005 sheet and 6063 extrusions anodise most evenly.
Wood-grain
A sublimated timber pattern over powder coat, giving the look of timber battens without rot, splitting or re-oiling.
Brushed or sandblasted
Mechanical textures under clear anodising or clear coat for a refined metallic look.
Pre-treatment
Chrome-free or chromate conversion coating before painting is critical for adhesion and filiform corrosion resistance, particularly near the coast.
Colour affects heat. Dark blades absorb more sun and re-radiate some heat towards the glass; light, reflective colours stay cooler. For deep louvres the effect is small, but for perforated screens close to glazing it is worth considering.
Fixing methods and installation considerations
- Into curtain wall or window frames: brackets bolted through the mullions, with the extra wind load on the shading checked against the frame design
- Onto concrete or masonry: outriggers fixed with chemical or mechanical anchors, using thermal break pads to limit heat bridging through the insulation
- Onto steel structure: clamps or bolted cleats, with isolating washers between steel and aluminium
- Free-standing: independent posts and beams for canopies, walkways and screens set on their own foundations
- Movement: slotted holes and sliding joints for thermal expansion along long runs
- Maintenance access: enough clearance for cleaning the glass behind the shading, or walkable brise soleil designed as a maintenance platform
Profiles can be supplied cut to length with end caps, pre-drilled and notched, ready for the installer to assemble into louvre panels. Pre-assembly on the ground is often faster and safer than fitting individual blades at height.
What to include in a shading system enquiry
- Product and locationLouvre, fin, brise soleil, awning, canopy or screen, and which façades or openings it covers.
- DimensionsOverall size, projection, blade width, spacing and angle, spans between supports and panel thickness.
- DrawingsArchitectural elevations, curtain wall or window details, site photos or a reference image.
- Structure and loadsWhat it fixes to (concrete, masonry, steel, curtain wall) and the design wind speed or code.
- Material and finishAlloy if specified, coating type, colour and the required coating standard.
- Quantity and deliveryQuantities, destination, packing needs and any phased deliveries; we supply on EXW, FOB, CIF or DAP terms with mill certificates (EN 10204 3.1).
References and standards
- EN 13561 – External blinds and awnings: performance requirements including safety
- EN 14501 – Blinds and shutters: thermal and visual comfort, performance characteristics and classification
- EN ISO 52022-3 – Energy performance of buildings: solar and daylight properties of solar protection devices combined with glazing
- EN 1991-1-4 (Eurocode 1) – Actions on structures: wind actions
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- Qualicoat – Specifications for coatings on aluminium for architectural applications
Aluminium (aluminum) sunshade systems: frequently asked questions
Are external sunshades better than internal blinds?
For cooling, yes. External shades stop sunlight before it passes through the glass, so most of the heat stays outside. Internal blinds only absorb the heat once it is already in the room. Internal blinds remain useful for glare control and privacy.
Should I use horizontal louvres or vertical fins?
Use horizontal louvres on equator-facing façades, where the sun is high, and vertical or angled fins on east and west façades, where the sun is low in the morning and evening. Many buildings combine both.
Which aluminium alloy is used for sun louvres?
6063 in T5 or T6 temper is standard for extruded blades and frames because it extrudes into complex hollow sections and takes coatings well. Heavily loaded outriggers may use 6005A-T6 or 6061-T6, and panels are usually 3003, 5005 or 5052 sheet.
How far can an aluminium louvre blade span?
Typically about 1.5 to 3 m between supports, depending on blade depth, wall thickness, wind load and the allowed deflection. Larger airfoil blades span further. Each project should be checked by calculation for its wind load.
Which finish lasts longest outdoors?
PVDF coatings to AAMA 2605 and anodising of 25 µm or more give the longest colour life, especially in strong sun and coastal air. Super-durable powder coatings to AAMA 2604 or Qualicoat Class 2 are a cost-effective choice for most buildings.
Can adjustable louvres be motorised?
Yes. Rotating blade systems can be driven by linear actuators or tubular motors, linked to sun, wind and rain sensors or a building management system, so the blades track the sun and close or park in high wind.
Need aluminium louvres or shading profiles?
Send elevations, blade sizes and finish. We will propose suitable sections and alloys and quote delivered supply to your site.
