to answers trap addict question to me i used the bleach strait i put it in a pump up style of sprayer so i could control it better. sq eye you are 100% correct about the risk of some steaking but the home that i have done this on was getting new fascia boards and and i truly should have stated that in my frist post and thank you for pointing that out to everyone,and now inspector D unless this is a small area(3sq ft or less)i would not use oil of any kind on a roof the risks to safety in my opion just are not worth it,and being on a roof for most poeple is scary enough now if was siding(not wood though)i would agree with you 100% but you have to keep in mind the roof is the place where the home owner is the most likely to get very very hurt if he/she slips up there also think of if like this dry roof most poeple are 85%stable wet roof brings that down around near 60-65% oil slicked roof more than likely around 40%stabe and the biggest thing that happens is fear more than the oil,they would start to slip and brace them self then in an instatend regain traction but are so froze up in fear could still topple over and please inspector don't take this as a but reaming from it is not.you do give very good advise it is just this one is alittle shaky at best IMHO