Rain screens and fixed louvres can be cleaned by robot only if the blade pitch leaves at least 60 mm of clear tread contact and each blade is at least 120 mm deep. Shallower or tightly packed louvres should be cleaned by hand, not by machine.
Why are louvres harder than flat glass?
A louvre is a row of tilted blades with gaps between them. A robot chassis needs continuous contact to hold suction and drive, and blades spaced 30 to 40 mm apart give it neither. The blade tips are also where water sits and minerals collect, so a machine that skims the face still misses every tip. Add the fact that louvre blades are often thinner than structural glass panels and you have a weight and pressure problem on top of a geometry problem. This is why most louvre cleaning still happens with poles, pads and a lot of patience.
| Surface | Robot suitable? | Reason |
|---|---|---|
| Deep brise-soleil (>120 mm) | Yes, if pitch >60 mm | Continuous support |
| Fine louvres (<40 mm pitch) | No | No suction contact |
| Wire / mesh rain screen | No | Cannot walk on mesh |
| ETFE cushions | No | Point-load risk |
| Flat / pitched glass | Yes | Designed for it |
What geometry makes louvres robot-friendly?
Two numbers decide it. First, blade pitch: if the clear opening between blades is 60 mm or more, a compact machine can bridge and drive. Second, blade depth: 120 mm or deeper gives the roller enough face to work. Wide aluminium brise-soleil at 45 degrees, common on office towers, can be robot-cleaned because the blades are deep and the pitch is open. Fine horizontal louvres on a plant room wall are not, and no amount of tinkering fixes that. Check the drawings before you promise a client anything.
How do rain screens differ?
Rain screens are usually a wire or mesh fabric held in tension in front of the real facade. They catch dust and let it sit, and the film builds up in vertical streaks. A glass robot cannot walk on mesh, full stop. Rain screens get cleaned with soft brushes and a controlled rinse from a platform, or in some designs they are simply replaced. Treat any mesh product as a manual cleaning job and price it per m² accordingly. Do not let a supplier tell you a skylight machine will handle it.
What surface should never get a robot?
Avoid machines on perforated metal, mesh, ETFE cushions and any glazing rated below the point load the chassis applies. ETFE in particular looks like glass and is not: a 25 kg machine with suction load can create local stress the pillow was never designed for. Also skip robot work on very small pane grids where frame lines stop the machine every 500 mm. The rule is simple. If the surface cannot give the machine a continuous, load-rated plane, use people.
Can a robot clean the frame behind a rain screen?
Often not, and that is the point. If a rain screen stands off the facade, the real glass behind it may be barely visible and barely dirty, because the screen takes the weather. Clean the screen and the visible glass stays acceptable. Where you do need the glass behind the screen cleaned, you have to remove or hinge sections of the screen, which is a different trade and a different quote. Be clear with clients that a rain screen is a shield, and cleaning the shield is usually the whole job.
How do you price non-standard surfaces?
Price them per square metre of actual working surface, not per square metre of floor area, and add the access time. Brise-soleil at 45 degrees has far more surface area than the wall behind it, and every blade is a separate run. Lifting, dressing and reaching louvres can triple the labour versus flat glass. Quotes that ignore this leave the contractor working at a loss, and contractors who under-quote non-standard glass tend to cut corners where the client cannot see. Get the geometry drawings before you commit to a number.
Related reading: square metres per hour and battery figures, and the contact our team.
Key Takeaways
- Robots can clean louvres only with blade pitch over 60 mm and blade depth over 120 mm.
- Rain screens made of wire or mesh are always a manual or replacement job.
- Never run a machine on ETFE cushions; suction loads create point stress the membrane cannot take.
- Check facade drawings before promising robot cleaning on any non-flat glazed surface.
How do you inspect louvres after a clean?
Inspect from inside the building, not the street. Stand where staff or visitors stand and look up, because that view shows the underside of every blade and the streaks that face inward. Take photos before and after from the same spot. On office facades, the inward face is the one that gets complained about, and it is the one a street-level check never sees. If the inward face is dirty, your clean missed the part that matters, whatever the outward view suggests.
Check the blade tips too. Dust and minerals collect there and show as a dark line along each edge. A pad run along the tips after the main clean removes them, and it is quick on a facade where the blades are accessible.
Can you clean louvres without taking the facade out of service?
Usually yes, if you work in zones. Close one bay, clean it, reopen it, and move along. A louvre facade does not need a full shutdown the way a large platform job often does. Plan the zones around the building’s use, keep a walkway clear, and post a spotter. The disruption is far lower than a suspended platform, which is one reason operators choose manual poles for louvres rather than a rig. Keep the crew small and the zone tight and nobody notices the work.