Anyone here cleaned any flat or low pitch commercial roofs? I have an opportunity to possibly work with a group of contractors that apply roof coatings, and reapply at intervals to maintain warranties. At this point, I can only guess at what sort of price to charge and what production rates to expect. Let's say we're talking about fairly small roofs, 5,000- 20,000 square feet, and relatively low, say, 20-30 feet off the ground. Built up or membrane roofs, not metal. Can anyone chime in with any information, please?