POWER WASHING CONCRETE

Source:www.stonediamondtool.com Date:2018/3/15 Read:465

To clean concrete effectively, use a power washer with a pressure rating of at least 3000 psi and a flow rate of at least 4 gallons per minute (gpm). Although higher pressures may be required to remove tough contaminants such as paint and heavy tire-skid marks, most power-washing contractors agree that 3000 psi will do the trick for almost all cleaning jobs.

Once an adequate water pressure is established, flow rate determines the cleaning speed, especially how fast contaminants are flushed from the surface."You can blast at 10,000 psi, but if you have a flow of only 2 gallons per minute, you're going to have a pile of mud sitting there," says Barry Woods of Hydro Pressure Systems, North Hollywood, Ca. Heavily soiled concrete, therefore, requires higher flow rates.

Several contractors recommend a power washer with a volume output of 5 or 6 gpm. When cleaning vertical surfaces, higher flow rates are not as critical because gravity helps contaminants flow from the surface.

To improve cleaning speed on large flatwork areas, many manufacturers offer wheel-mounted power washers that resemble a lawn mower. Within the metal housing are nozzles mounted on spinning bars. According to Larry Hinckley, general manager of Delco Cleaning Systems, Fort Worth, Texas, workers using standard power-washing wands can clean roughly 900 square feet the first hour but the workers tire and and become less productive as the day progresses. Using a walk-behind washer, he says, workers can clean 3,000 square feet per hour and maintain that productivity throughout the day.