Q: We have a “green roof” that is not meant to be green. Moss is collecting on one side of the asphalt roof. It is otherwise in good shape. What I have learned so far is that it should not be power-washed with high pressure. How should one remove the growth, and who does this type of work?
JNR Answers below.
A: You are right, we always will do an inspection and whisper to the roof to see what it needs. Every situation is different and we want to maximize the life of your shingles.
To clean either algae or moss, the standard practice among experienced companies recommends putting hiring professionals, someone who is completely legal and has the Department of Agriculture license for the treatment. We recommend a treatment first to get the growth nice and dead, then come back a month or so later when it is all dead and brownish and doing the removal. The reason we would do it this way is because dead stuff detaches easier and is easier on the shingles to do it this way. Algae and moss will subside with rain and weather but this is a long term game plan approach. It will loosen over time and may be removed with a leaf blower. Depending on the structure, we always do an inspection with the treatment for best practices moving forward.
JNR echoes the warning not to expect the moss to disappear instantly. We want to get you the most life out of your composite shingles by relying on our organic treatment and by keeping it leak tight.
Don’t be tempted to rush getting the moss off faster by having someone do a high pressure power-wash, or scrub in the bleach solution, or brush or scrape it off — even though you may find advice on the Web recommending these as long as you are gentle. The key is the roof that you have, what is best for it. Sometimes a low pressure, very low after we come back to do the removal can benefit.
An ounce of prevention is worth a pound of cure. Meaning, regular maintenance treatments to keep it from even growing in the first place.
The average cost to treat a roof is around 390.00.
JNR and his crews work from ladders, the ridge and safety harnesses. A typical charge for a single-family home ranges from 390.00 (treatment only) and up depending on the job and what needs to be done. The company’s website touts use of “a custom cleaning solution, specially blended to meet demands of each project.” But in most cases, the solution used on roof moss is “Safer” a registered organic with the OMRI label. Safe to use around gardens and plants.