I also us 12% - 15% chlorine in a 6 gal container and add 4 oz / gal of an industrial detergent that lifts dirt and prevents streaks on windows. I feed this thru a down stream injector at 1:8 ratioso I am applying 1.5% to 2% to the house. Works great. I can stand way back when applying (25 deg) and rinsing (15 deg) so I don't get sprayed. No need to get close or spray each board. If gutter or facia board has black streaks, spray on gutter zap and rinse. At the foundation where the brick meets the ground, use a turbo nozzle and you won't get the dirt thrown back on you. For tall gables, second floors, dormers on roof and chimney, I use a 0 deg or 15 deg size 20 nozzle and it throws the chemical all the way to the top. Let set a few minutes then rinse with a 0 deg or 15 deg size 10 nozzle. The size 10 nozzle throws the water further because of less restriction. You don't need the pressure, you need the water volume to rinse if you let the chemical do the work. I only use my ladders and extension wands 2 or 3 times a year. I use cold water, 3K PSI @4 GPM on a portable unit. I use only flow sensative unloaders to keep hose limp when not spraying and to eleminate kick when you pull the trigger. I have had no need for hot water on residential or commercial buildings. The portable unit (on three wheels) comes out of a van easily and only requires 100 feet of hose. I usually position the machine at the left front and then the right front of a house and can reach everthing. I use velcro straps to hold the trigger open, and slide it up and down to start and stop.
Sorry to ramble. Just a few thoughts that work for me. Oh one more thing. Because of the speed that I can do a house, I average $80 to $120 / hour. The cost to the customer is very competetive with my competition because they take twice as long to clean a house. The customer pays the same, but I make more money per hour and Time Is Money.
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Baldwin Power Wash, Inc. serving the Gulf Coast between Mobile, AL and Pensacola, FL.