While it may seem like a good idea to use a power washer on faded brick floors, this is not advisable. Bricks are made from a composite slurry, so exposing them to a high-pressure stream of water and/or chemicals can cause the brick to disintegrate and crumble. Instead, focus on using no more than 100 psi to 1500 psi of water pressure. As an indication of how much this is, a garden hose usually yields 40 psi of pressure. Rental power-washing machines tend to produce streams of 3,000 psi and upwards. This can rip your bricks apart.