Hi
Depending on what i am cleaning off depends on what chemical we use.
99% of fascia cleaning/roof cleaning is UBIK 2000 diluted to around 1:4 1:5
I use a pump up sprayer (ebay or home base £5 - £20) The mixuture is sprayed over the roof and then allowed to soak in.
Then just clean off.
Depending on the job, i might mix things up. Like using fairy washing up liquid mixed with iso alcohol or maybe even a solvent.
The brush was an Gardiner Dual Trim Super lite sill brush fitted with low flow fan jets
