Please forgive me as I am new here, and while I've been reading for the past couple hours, I do have a couple elementary questions. We do a small amount of pressure washing for our customers, mainly for our lawn and landscape customers, but nothing of significance - mainly for customer service reasons. In all honesty, we turn down about 30-40 customers per year just for pressure washing driveays and walkways alone. This is something we've budgeted a few thousand dollars to jump full into, so we're about ready to flip the switch and get on board and really get into this side of the biz as well. Nonetheless, here are my questions.. 1. What is the best way to apply chemicals to driveways and walkways? I've heard running chemicals through your PW can cause a lot of harm to the machine. Is this something I can spray on the concrete with merely a 4 gallon backpack sprayer and a little dwell time? 2. For just standard dirt, what's the best chemical to put down first? 3. What is TSP and what does it stand for? 4. Best way to apply concrete sealer after concrete areas are cleaned? Thanks for the help, and there really is a lot of great info here!