In article ,
Ramon A wrote:
I have a fairly extensive area of block paving as a front drive, etc but it
is on the north side of the house so it has a tendency to remain wet and
dank, and suffers from moss along the cracks and algie+grime on the surface.

I scratch off the moss with a blunt tool quite effectively but cleaning the
algie+grime is more problematic.

I have a pressure washer which will clean the algie+grime but it also brings
out the SAND.

any suggestions please for an effective treatment to kill and disolve the
algie+grime stains so that i can then wash off with lower water pressure??

Use a handful of sharp sand, some water with detergent in it and a
stiff broom. That is very effective, and you can then wash off the
sludge with just a hosepipe - or even a bucket in a hosepipe ban
area. A person in reasonable health will take only a minute or few
per square metre, depending on how bad the growth is.


Regards,
Nick Maclaren.