First of all neither Dicor nor Alpha recommended using any of the commercial rubber roof cleaners or protectant… both actually strongly recommended not to use them at all, that is until Dicor bought out one of the companies making them… They will do more harm than good…
However washing you roof with a detergent will keep the roof both looking good, can reduce black streaking, and it will make checking for leaks or problems very much easier… it is not a waste of time or effort...
Using large commercial roofs as an example for not cleaning the roof is just a way to justify not wanting or not doing it, the 2 roofs can not be compared…
first of all there is no such thing as a good flat roof... the commercial roof is 2 to 3 times thicker usually (60 mil) than what is used on the RV roof…
It is impossible to make those comparisons between large commercial roofs and a 400 sq. ft. RV roof…
rubber roofs have helped reduce the cost of these large roofs, due to building codes, height limitations, and cost, they are still the roof of choice in these applications…
but cleaning them would be cost prohibitive… the volume of water and the rate it would need to be applied makes thoroughly rinsing one almost impossible and if it isn’t rinsed well washing would be a total waste of time on any roof…
few commercial roofs have the dirt and oxidized rubber running down the sides of the building making an unsightly mess of the building’s exterior either…
not to mention the risk of damage that can be caused by dragging the heavy cleaning equipment that would be used and fire hoses to provide the high volume and high pressure water needed trying to rinse a large area like that…
these commercial flat roofs are a constant and royal PITA and require budgeting for their constant maintenance and replacement… they are popular because they are the lessor of the evils between other types…
these things are not a problem on a 400 or less sq. ft. RV roof because they can be easily be washed and thoroughly rinsed, and require no special equipment major time or cost… talk about apples to oranges…
