Some roofs can be tougher than others.
Just dropped a job because we started this guys roof. One of my crews went out, hit it with our normal mixture, did not even lighten it. Went back a couple days later and hit it again along with the 2 houses on either side of his. Both neighbors houses cleaned no problem, looked great, This guys house still looked like we had not touched it
I went out with the same crew on a Saturday morn. Got up on the roof myself, sprayed a non-dilluted TSP-Bleach and Dawn Mixture. Now the stuff came off...mostly, lightened all of it, took off 85% of it. (Remember...Rinse-Rinse-Rinse..then rinse the bottom of the drains, then rinse again)
The same crew went back Tuesday, Did 2 more houses on the same street...(never had that happen before..5 roofs on 1 street within 8 days) and hit his roof to finish it. (with our normal mix, figured it would not need the heavy stuff again) The 2 new roofs looked great, this guys roof did not budge one bit from what we got off on Saturday. He was frustrated, threatened to call someone else. I decided to let him. Too busy to do the same house 5 times in a bit over a week! Have no idea what was going on there...but, the other 4 neighbors handed out our cards and we got 2 more roofs yesterday from the same street...not just the same neighborhood, but all of these are on the same street within 2 blocks of each other.
Anyway, his roof appears to be in good shape and normal, just for some reason the fungus is being un-beleivably stubborn. But we more than made up for what we lost on his with the others. (He was the first caller...the others just saw us at his house and called us)
