Thanks Ed will give what you suggest ago and do my first hypo mix at a 3 to 1 ratio. After the 20 mins is it ok to just hose/rinse the area with a garden hose with just tap pressure or do you need to rinse with high pressure ie FSC etc?
Rodger the photo was not the best, it was a before photo, the town is a town house and does not get much sun on the drive. The owners have had a lot of work done recently after just buying it so not sure what the rust looking colour marks are or were but they cleaned up no problem. I have attached another photo which I found on a google search which is very similar to the marks I am looking to remove.
Thanks again
Cowan,
What I'd do is re-clean the area in manageable sizes, then apply a hypo mix take it down to 2:1, allow to dwell for 15-20 mins then wash off, if you do the area in sections then whilst you are cleaning one section another is dwelling.
Dwell time will be all from the photo you attached if the lichen is that bad.
If you haven't used Hypo before here is a quick do's & don'ts
Watch your run-off, as it will kill grass, tender plants and if there is a pond close by (as in the run-off will go into) then don't use, it will kill fish etc.
Water first then the hypo when mixing, this stuff will burn your skin, so PPE is important, goggles, decent gloves, Nitrile is best, full water proofs etc.
If you are working close to windows & doors I'd mask/cover them up.
Any wood near by, as the hypo will bleach this out if you are not cleaning it so again mask/cover.
This should get you started.
