Power Washing
Did you know that power washing alone won't fully clean areas with big dirt build up and moss?
It looks clean but in order to really clean it you need to first spray it (and a garden sprayer does a great job) with bleach water and tsp. Let it sit for a minimum of 20 mins and do it on a dry day.
Last year I did my concrete in the backyard and the sun did the rest… didn’t even need to power wash it… be careful of what you are spraying this near as it will burn plants so hose them down before and after with regular water just in case.