I think all that chemical could of been applied through a wfp much safer, a lot less over spray and direct onto the surface, and after the clock has spun round a bit use the brush it agitate.
For a service like that on that house you would be talking a few thousands of pounds, so plenty of money in the job to allow you to put up tower scaffolding up to work off properly.
Am not looking to get into this type of work, well not just yet but I will be setting another tank up with one of them 12v pumps and using it to apply chemicals were required, this will be hypo if pressure washing virosol, hd degreaser, al even put fairy liquid through it
