Janet Baraclough wrote:
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my pressure washer arrived last week. do you know i didn't realise
that the pavings slabs were supposed to be grey and not black(!!).
so far i have cleaned half of them over the past two days.

When we had a paving expert here, iirc he commented that some
coloured ones are only surface- dyed , and that powerwashers are
liable to remove the top surface.

www.pavingexpert.com.


The surface-dyed ones that I've used aren't dyed after manufacture but
during, and the surface colour is about a quarter of the flag's depth,
usually about 8mm....I doubt that any pressure washer could remove 8mm of
pressed concrete, and if there is a pressure washer around that could do
this, I'd hate to think what it could do to a car, especially mine which is
only held together with rust and string.

That said, I don't agree with PW'ing paving anyway (I lay it for a living)
given that it removes the 'grout' whether that be a cement mix or silica
sand, and allows the dreaded dandelions in, closely followed by swarms of
ants and other mining insects.

A fairly strong alkali solution will clean most paved / concrete / wooden
surfaces, and in a lot less time than a PW.