We can deal with your comp roof moss and fungus problem a couple of different ways. We can use the same chemical and technique we use on the shake roofs. The process works the same way and has the same benefits as on shakes. It just doesn’t work for as long because there is nothing for it to soak into. The problem with that process on comp is the expense. The chemical has penetrant, preservative and fire resistant properties that are not relevant for your roof, but that doesn’t make the product or the process to apply it any less expensive. What I am trying to say in a nice way is this – it isn’t worth it. We’ll take your money for whatever you want us to do, but I would not pay me my own money to use that process on my own roof.

The vast majority of the time we use a dry chemical method that is much more cost effective and makes a lot more sense for your roof. If the moss is about the size of your big toe or larger, we gently scrape the worst of it loose and blow it and any debris off the roof. We then blow out the gutters as needed and clean up the fall-out. The moss that is not easily dislodged and the minor amounts are left for the chemical to take care of. We then spread the chemical along the ridges, hips and above areas of moss as needed. Over the next several weeks, the rain will dissipate the product through the areas of moss. After a season or so there may be some residue of the moss left which can be swept off but we have yet to have anyone do that. It generally will erode and go away. What we do not do, not ever, is pressure wash the roof. We don’t do it for the same reason we don’t clean the kitchen floor with a fire hose. Your roof material was not made to be blasted with a 1500 to 3500 psi torrent of water. It was made to be rained on.