- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 25 Feb 2019
Don’t Look Down! – Skyscraper window cleaning through the ages
Cleaning high-rise windows is nothing like cleaning the windows of your house or bedroom, which only needs a damp cloth, a squeegee, some window cleaning detergent or a bucket of soapy water and some elbow grease. When you’re cleaning windows on the 81st floor of a skyscraper, at the dizzying height of half a mile above the ground, things take on a drastically different feel.
Cleaning skyscraper windows is a dangerous job and not for the faint-hearted. It takes a certain type of person to be able work at heights way above the ground. Skyscraper window cleaners are skilled professionals, aware of the perils of their job. One slip or mistake and people could die, so safety is always foremost in window cleaners’ minds. Safety drills are performed regularly and everyone knows exactly what to do while suspended high up in the air.
Wind can play a big part too. Way up on the side of a skyscraper, winds generally blow at a much greater speed than down on the ground, which makes it absolutely vital for cleaners to be equipped with the relevant safety equipment.
 In the past
In the past, high-rise window-cleaning was a relatively simple affair. Tthe windows could open, so that meant a team of dedicated men, all with a good head for heights, could simply climb out onto the ledge, hook their leather harnesses to the side of the windows and get busy. And although the ledges were fairly narrow, they were safe to walk on.
But with the advent of glass curtain wall buildings in the early 1950s, all that changed. The windows became the building’s façade and, as a result, they no longer opened. This meant that window cleaning had to be done from the outside and this posed its own set of problems. Buildings now had to be built with flat roofs in order to cater for window-washing equipment. Window-washing platforms that could move up or down had to be suspended from rails or tracks on the roof.
As window-washing technology became more sophisticated, glass curtain wall buildings changed too. At that time, window-washing equipment included arms that could act as supports for both washing and hoisting and skyscraper building owners had to devise window-washing maintenance schedules to keep all windows clean.
Some skyscrapers, such as the Petronas Towers in Kuala Lumpur, Malaysia, are built with a complex system of multiple setbacks, or step-like recessions in the walls, which rule out any traditional form of window-washing. Instead, the architects had to design booms that could telescope and extend far enough to allow the cleaning rig, manned by brave window washers, to reach all the windows that needed cleaning.
The kind of tools and equipment that protect workers from dangerous incidents and help them clean windows include rope protectors, a descent mechanism, a safety rope, rope-grabbing tools, a lanyard and suction cups. Workers washing windows on skyscrapers are attached to an anchor that’s mounted on the roof, allowing them to clean the windows as they move jerkily down the building. As they manoeuvre downwards to the next floor, it appears as though they drop a few metres then abruptly come to a halt – a truly heart-stopping moment.
Over the years, many different mechanical platforms and devices have been used to help professional widow cleaners get to where they need to be to clean the windows properly and safely. The most common of these are the Bosun’s Chair, the Boom, the Carriage and the portable Davit.
The boom is one of the oldest and most commonly used mechanical contraptions. It consists of a scaffold, or platform, that can carry a whole team of window washers. Fixed to the top of a building, the boom is a permanent window-washing system that can be used as and when required.
Providing a superior and more modern alternative to the boom is the carriage. A carriage is mounted on top of a rail on the roof and is able to move to the left and right over the building’s façade. It can also accommodate multiple washers and, because of its movement across the face of a building, it has a clear advantage over a boom.
 Portable Davit
The portable Davit is one of the cheapest mechanical options, enabling access to most areas of a building’s façade. It can also carry a group of washers. The davit has metal arms from which lines are suspended. These arms swivel, allowing the window-washers to set up equipment on the rooftop, from which they then swing out over the skyscraper walls.
 Bosun’s chair
This is a fairly modern invention and is meant for a single window washer. It takes the form of a comfortable, strap-in seat. Using a bosun’s chair, cleaners can access very difficult-to-reach areas of a skyscraper. It is also ideal for protracted periods of dedicated window cleaning.
 Related articles on Designing Buildings Wiki
Featured articles and news
Bamboo pavilion built at London South Bank Uni.
Bringing in an expert.
Why the lowest price isn't sustainable.
The Most Economically Advantageous Tender.
Pipe dream or possibility?
The New Rules of Measurement.
Prioritising Sustainable Development Goals on projects.
The Architects Registration Board.
How BSRIA monitored the performance of new homes.