I will beat anyone who is fully licensed to clean a roofs price.  Guaranteed to be the lowest competing bidder for moss removal in Portland Oregon.  Any roof work that you may need I will show you photos and will fully inspect the roof while on the job.  I am not a low bidder by any means but there are so many knuckle head companies out there bidding low that they are not even on the same or fair playing field.  Throw those bids away if they are not licensed bonded and licensed with the dpt. of agriculture for treatments on roofs.