- 1). Attach the concrete-cleaning nozzle to your power washer. Add a concrete-cleaning solution to the power washer's reservoir according to manufacturer's instructions.
- 2). Slip on a pair of thick rubber gloves to protect your hands from the cleaning chemicals. Put on a pair of goggles to protect your eyes. Turn on the power washer and climb an extension ladder up to your roof.
- 3). Hold the pressure washer approximately 3 to 4 feet away from the concrete tile, moving the power washer back and forth as you clean. Start at the top of the concrete tile roof and work your way down as you clean.
- 4). Move the power washer closer to the concrete tiles if you encounter a tough stain. Hold the power washer at a distance of 1 to 2 feet, but no closer. Resume cleaning at a distance of 3 to 4 feet once you remove the stain.
- 5). Move the pressure washer back and forth, moving from level to level, until the first side of the concrete tile roof is clean. Repeat the process on the other sections of the roof.