There are two ways professional window cleaners can clean the external windows of a high rise commercial buildings in the city of Perth. As discussed before in previous blogs, one is rope access where the building has anchor points on the roof and we have the ability to lower ropes from the roof to access the outside facade on the building. See our blog on Rope Access.

Another way of accessing the external windows of a high rise commercial building is via a BMU.  BMU stands for building maintenance unit, it’s the  platform that you see going down the outside of a building connected to the roof by two metal chords this is also known as a cradle or boat; the most common term is BMU.


During the late 90s many of the buildings in Perth decommission there BMUs and chose to access the outside of the facade of a building via rope access. However, there are a number of buildings still left in the city of Perth that prefer to use the BMU rather than Rope Access.

The BMU is different on each building due largely to the fact the at each building has its own unique access requirements. Therefore, each BMU is made especially for that building and therefore the user needs to be trained on each one before use.

The BMU must be serviced on a regular basis and must be checked by the user prior to use.

The BMU allows the professional window cleaning company such as Window Wipers to lower themselves on a drop exactly where the windows are and takes the user back up to the top of the building on completion of that drop. The driver then moves the BMU horizontally on the roof to the next drop and it continues around the whole building in the same manner until complete.

Some BMUs move along a monorail on the roof of the building via remote control, while
others have castors and using a remote control are positioned by the operator.

The photos used in this blog show Window Wipers staff using BMUs in Perth CBD.



(In this photo we have our staff taking a photo from the ground, showing Rope Access Team abseiling the building next door to our staff in the BMU on the neighbouring building.)