Every tall building in London has a window cleaning problem that its architect solved on paper and its facilities manager inherits in practice. The glass has to be cleaned several times a year, the people who clean it work at heights that would end a career if anything went wrong, and the choice of how they get there was made years ago by someone who never has to sign the permit to work.
There are four ways to clean the outside of a tall building, and each one carries its own equipment, its own legal duties and its own cost.
Water fed poles
For anything up to about four storeys, the water fed pole has replaced the ladder almost entirely. A carbon fibre pole carries purified water to a brush head; the operator stays on the ground, the glass dries without streaks, and nobody is working at height at all. On a mixed estate of low-rise blocks it is the cheapest and safest method by a wide margin.
The limit is reach. Beyond around 20 metres the pole becomes unmanageable, and on a building with deep reveals or set-back floors the brush cannot get to the glass.
Rope access
Rope access technicians, the abseilers, are the fastest way to clean a tall building that has no permanent equipment. Two ropes per operative, anchored to tested eyebolts or a roof rig, and a team can work down a facade in hours. It needs no scaffold and no road closure, and the operatives are trained and certified to an industrial standard that is, in practice, more rigorous than most of the trades working on the same building.
The dependency is the anchor points. Rope access only works where there are certified anchors on the roof, and those anchors must be load tested every twelve months. A building whose eyebolt test certificates have lapsed cannot be cleaned by rope until they are renewed, which is the single most common reason a scheduled clean is cancelled.
Cradles and building maintenance units
Many tall buildings were designed with a permanent cradle: a platform suspended from a roof-mounted rig, sometimes a simple davit system, sometimes a full building maintenance unit on tracks. Where it exists and works, it is the most controlled method of all. The operatives stand on a platform rather than hanging from a rope, they can carry more equipment, and the system can be used for glazing replacement and facade repairs as well as cleaning.
Where it exists and does not work, it is the most expensive problem on the building. Cradle systems need a thorough examination every six months under the lifting equipment regulations, the operatives need specific training on that system, and a unit that has been left unused for two years will usually fail its inspection. Facilities managers in the capital who are weighing up cradle window cleaning in London against rope access should start by finding the cradle’s last examination report, because that document decides which option is actually available.
Powered platforms
Cherry pickers and mobile elevating work platforms fill the gap for buildings with no anchors and no cradle, and for one-off deep cleans. They need ground access, a licence if they stand on the public highway, and an operator with the right ticket. On a city centre street with pavement cafes and bus lanes, the permit can cost more than the clean.
Who is responsible for what
This is where the arrangements most often go wrong. The building owner or managing agent is responsible for the condition and testing of any permanent equipment: eyebolts, davits, cradles and fall arrest systems. The cleaning contractor is responsible for the competence of its operatives, its method statements and risk assessments, and for refusing to work where the building’s equipment is not certified. The two responsibilities meet at the permit to work, which is why a reputable contractor will ask for test certificates before quoting and will not be talked out of it.
A contract that is silent on who tests the anchors is a contract that will produce a cancelled clean and an argument about whose fault it was.
Scheduling around the building
Tenants notice window cleaners. Rope access teams passing office windows at nine in the morning cause complaints; the same team at seven causes none. Cradle work on a residential block needs notice to residents and, on some buildings, a schedule that avoids school holidays. The best contractors plan the year with the building manager in January, fixed around the equipment inspection dates, and work the same cycle every year so that the glass never gets to the point where a deep clean is needed.
What to put in the contract
State the method for each elevation, because a building often needs more than one. State who is responsible for anchor and cradle testing and who holds the certificates. State the frequency, the working hours and the notice to occupiers. State what happens when weather stops work, because wind speed limits apply to every method above ground level. And state how the contractor reports faults it finds while up there, because the people who see a building’s facade most closely are the ones cleaning it, and a cracked pane or a loose panel spotted in March is a great deal cheaper than one that falls in November.