In a recent post Bob advised against someone doing exposed aggregate by themselves citing the difficulty in determining just the right time to wash off the concrete to expose the gravel. In my own case, I need to lay an exposed aggregate sidewalk myself for financial reasons. Can anyone offer some general tips as to when to take the hose to the finished sidewalk? Also, is it better to have the aggregate mixed right in with the concrete, or just sprinkled on top, or both? Thanks for any help you can offer!