Getting cement to whiten may require more than pressure alone. Cement is pourus and may require a special cleaning agent to assist the process. Using a combination of sodium hypochlorite and with tri-sodium phosphate seems to work quite well. Using a chemical resistant pump sprayer may work best to apply the agent accurately, for this solution is not friendly to grass or other landscape. Allow the whitener to dwell for approximately 15 minutes, than using a 0 degree turbo nozzle wil finish the job. These are pics of a job in South Plainfield, N.J.
"Why is it my gutters get those ugly black lines, and they were just recently installed?" We are asked this question frequently. These lines are not dirt. They are actually a type of oxidation called "electrostatic bonding". They cannot be removed by any type of pressure washing. It takes certain chemical to counter act the oxidation. http://www.thompsonpowerwashing.com/ has a simple and affordable way to restore your gutters to new condition. The cost is roughly 30 cents/ft for the first floor and 50 cents/ft for second floor gutters (depending on accessability, landscape, etc.).
Getting cement to whiten may require more than pressure alone. Cement is pourus and may require a special cleaning agent to assist the process. Using a combination of sodium hypochlorite and with tri-sodium phosphate seems to work quite well. Using a chemical resistant pump sprayer may work best to apply the agent accurately, for this solution is not friendly to grass or other landscape. Allow the whitener to dwell for approximately 15 minutes, than using a 0 degree turbo nozzle wil finish the job. These are pics of a job in South Plainfield, N.J.