just wanted to drop a line about this site and the great information available here. i started cleaning roofs about 12 years ago here in western North Carolina. i've spent over 10,000 dollars on the info you guys are offering for free.so people take note and listen these guys know there s*!t Chris from apple is the guru of roof cleaning . Ive been away from the business for about 6 years and with the economy the way it is I'm going to start cleaning again this spring again thanks for this great site Greg