pressure washer

[gamx]

Would a 100bar pressure washer be sufficient to wash a block paving driveway i.e. would it get rid of moss/dirt ingrained into the brick?

and what would be a decent pressure washer for the job?

[John Rumm]

[Rob]

Looks quite a job - just did 6m x 6m with a scraper/gouger and 3 years of muck and moss - about 5 hours.

Rob

[David]

The FAQ has an extremely useful formula to work out the cleaning effect, from that formula I gathered that Nilfisk pressure washers are much more powerful than many Karchers at the same price.

[The Medway Handyman]

Depends entirely on the flow rate. A cheap domestic @ 5.5 ltrs/min compared to a commercial machine @10 ltrs/min - the commercial machine is >70% more powerful.

Both will do the job, one will be 70% faster.

If its a one off or infrequent job, hire one, preferably with a 'Surf' or 'T Racer' type head. This will prevent splashback & speed up the job no end.

[gamx]

thanks all, that FAQ is good (actually the whole wiki:)) ill be needing it permanently so ill probably pay a bit more and get one with an induction motor (thanks again FAQ!).

[John Rumm]

I can recommend the T-racer add on. I was able to do 70m^2 of patio on a mid spec Karcher in about 2 hours using the T-Racer for the bulk of the cleaning, and the water broom for sweeping all the accumulated much off onto the lawn.

[John]

There must be better ways that don't involve ruining the surface of the blocks.

[The Medway Handyman]

Why would you assume pressure washing ruins the block surface?

Do you have any evidence? Do you have a better solution?

[John Rumm]

These were slabs rather than blocks, and washing has no detrimental effect on them.

Even block paving is usually done with concrete blocks which would also be relatively unaffected - although you would need to take care not to sweep the sand out. The T Racer would help there as well.