Cleaning Block paving - what's best

[Sloppysod]

As title says, what's best for cleaning Block paving and any tips to slow down or stop weeds growing.?
Please

[GiveMeABreak]

I use my Karcher pressure washer with patio attachment. It cleans up ant stone or concrete brilliantly. Just make sure there are no loose stones or hard debris in the way.

[Sloppysod]

Thanks Marc, I use my jet wash with a similar device attached, but seems to waste alot of water for little improvement.
My pavers are permeable, thought it was a good idea at the time, so as to allow water to pass through rather than run off and create a slippery hill I can the winter. . . .

[bobins]

If it's because the paving has gone a bit black or green due to moss and/or algae growing in damp conditions then the following does not constitute advice or recommendation.......

Apparently Benzalkonium Chloride - commonly sold as BAC50 - diluted down to 2-3% solution and applied on the hard surfaces with a watering can is good at killing off moss and algae and keeping it killed for many many months. However, it's use for this cannot be recommended as if used incorrectly or poorly or by knobheads it can cause damage It should not be allowed to get into waterways (streams, ditches, ponds etc) - no ifs, no buts. It should only be used once a year - no ifs, no buts. It's only good for hard surfaces - not lawns. BAC50 is used in an awful lot of common stuff - from bathroom mold removers, to some contact lens solutions, to hospital cleaners, etc, etc. It's not actually dangerous per-se, it's just it should be used by sensible people. You wouldn't go pouring bleach into a stream - and the same goes for BAC50. BAC50 is actually the main ingredient in a lot of moss and algae removers, it's just that it's mixed in with a lot of other things at the same time.
Once the BAC50 has done its job - a couple/few days should suffice - then a good pressure washing with a 'turbo' nozzle should clean the paving up nicely, assuming you've not got a sand infill Don't do it when it's scorching hot as it'll evaporate too quickly, and it might pay to wet the paving before you start. The moss and algae will give off an 'aroma' as it keels over
If the paving is just dirty, then don't bother with the bAC50 as it won't really help.

As for keeping the weeds down, good residual weedkillers for hard surfaces are few and far between these days. Ones for commercial use are fairly expensive and fairly restrictive on their usage, but for 'back garden' use you might want to look into 'Pathclear' weedkiller, though there are restrictions on its use as well It should be OK to use if you've got sand infill block paving, but not really recommended if it's an impermeable infill.
Read the instructions !!

[white exec]

Another vote for a jet-washer, with turbo lance (which minimises water usage).
We have a good bit of terracotta tiled pathway - very porous, and not a lot different from a coarse flowerpot (the worst kind ). The jet-wash chases all the blackening out. Just be careful with any poor grouting.

[GiveMeABreak]

Yes the water used is not as bad as you would think to be honest.

As for algae killer, I use the Pro-Kleen stuff that you dilute with water - great for keeping the water in water features algae free - as long as you don't have fish in there of course....