I put in a quote for a red tile roof, it is almost black in some spots, did a test of 10%SH @ 70/30 and let dwell for 10 minutes, it cleaned up some but not to my satisfaction. What is the average dwell time for this type roof?
You may have to reapply your mixture 2-3 times if the tiles are really black. Let it dwell 15-20 an a warm sunny day, cooler temps. longer will take longer.
