I started my pressure washing business here in Port Charlotte [ My home is actually closer to Rotonda / Englewood ] back in 1989. My son joined me in 1994 and we have been together ever since! With us, you never get a work crew, a trainee, or someone who can not speak English. :-) In the early 90's I learned that the roofing manufacturers had an association ARMA and that the ARMA had a specific method and specific cleaning agents set out in their Technical Bulletin, describing how roofing should be cleaned and saying DO NOT PRESSURE WASH" roofing. I added the cleaning system equipment to my trailer setup and have never power washed a roof since way back then. What an improvement! NO DAMAGE! NO BLOWING THE GRANULES OFF OF SHINGLES! Plus, the ARMA method lasts about twice as long!