Upon first noticing moss growing on roofs, it looks picturesque like a house straight from a fairy tale. But don’t get too attached, because moss growing on the roof can be a potential disaster. The moss itself is harmless, it will not cause health concerns like mold will. But the moss’s ability to retain moisture makes it dangerous to the longevity of your roof. When rainwater hits your roof, instead of being swept into the gutter, it becomes absorbed into the moss where it is held indefinitely. As you know, extended moisture on your roof is a hazard that could cause a whole host of dangerous issues.
As moisture becomes absorbed into the moss and is retained on top of the roof, the shingles will begin to deteriorate over time. Roof moss that has been ignored over a period of time will lead to a weakening of the shingles and subsequently, the shingles will begin to allow the water into the inner layers of roof. The moisture softens the roofing materials and allows them to be susceptible to the elements.
Mossy roofs that go untreated for long periods of time will often become leaky and will even cave in during the right conditions.
Even further, we all know that moist environments become an ideal place for mold to form. Once mold forms on your roof, you will have irreparable damage. It’s important to keep roofs moisture free to stave off the mold.
Eliminating current mold growth can be a process. You can kill mold with a mixture of equal parts water and bleach. Spraying the moss with this solution will kill it and prevent it from retaining water. There are also solutions available through your local home improvement store which will do the job just as well. You should absolutely under no circumstances use a pressure washer to aid in the removal. The pressure washer is likely to damage shingles.
If at some point during the removal process you notice that your roof has suffered damage, it is extremely important to call roofing professionals to have them check out the damage and recommend a proper fix.

Articles What to do about moss on the roof