Why do you clean paving stones?

Well the development on the High Street leading into St Mary Street is coming along, it's taken months to get around the corner below where I live but I am finally managing to have a slightly more peaceful nights sleep. That is until a new noise has introduced itself into my life. For the last few months a company has been asked to 'wash' the newly laid paving slabs. It happens from around 11pm and goes on for hours. With the worse and loudest generator powering the whole thing.

For your own health avoid these vans.

- firstly I have to ask why do you need to 'wash' paving stones?

- secondly it's not just water it is soap as well?

- thirdly if you are doing it do you have to repeatedly have to bang into the fencing time and time again just to make sure I am paying attention.

Sounds dangerous I wonder if it melts rubber tyres? also it's not wet because they have just been washing the floor it's just rained which seems to have done a pretty good job of washing and cleaning?