Quote Originally Posted by Doug Rucker View Post
First question is what size machine are you using, PSI/GPM?? When I clean driveways, I use cold water only, (at 3000psi/8gpm) and a 21 inch surface scrubber. For smaller driveways I may use a 3500psi/4gpm with a 16 inch scrubber.

You can pre treat driveway with a house wash mix if it is really dirty, heavy mold mildew build up, and let it sit a few minutes, then clean. Then when done apply mix again and allow to dry. This will really brighten up the concrete.

The most important thing when cleaning driveways is to make sure your surface cleaner is properly sized to your machine.
Awesome information!

Quick question about allowing the SH to dry; do you think the concrete would need to be neutralized to bring back the PH if I were to apply a sealer after drying?