Sometimes you can see it and sometimes you can’t see it. Sometimes the roof is buried and sometimes there’s only a spec of it. Regardless of the amount or visibility of it, what’s wrong with having roof moss? Patrick D. Morin shows us a great example of an architectural composition roof that has a case of roof moss and explains why that’s a problem.


I have a lot of people that ask me “Hey, what’s the problem with moss on an architectural composition roof?” and I wanted to show you this visual of how the moss forms in the little drain areas and then it feeds the spores down underneath the shingle and it actually starts growing and lifting up the shingle.
So, when you get heavy rain, anything out of the ordinary, all of this moss and support system that has lifted the shingle, it allows the water to get to the fasteners and continued water to the fasteners; you see how far the moss has grown up underneath there, continued water to the fasteners, which by the way are right there, you can see where the fasteners are, if water was able to run across this shingle in any direction because it has lifted up, you can see how these are lifted up. That all has been done by Mother Nature by allowing too much moss to form on these shingles, and they just lift them up and then all of a sudden water in getting into your building and you are trying to figure out why. That nail by the way is a low nail, should’ve been up another inch, most shingles put on by most contractors are put on really, really fast, they’re paid by the square and then you get one like this where they are put in at an angle and the head has poked a hole through that shingle already and boy if any water gets to that it is just going to leak. In a perfect situation as long as the shingles are sealed down tight, no problem, but when moss is allowed to form they lift as you can see there, those are lifted all because of moss and this is a very un-mossy roof, the other side of this roof is horrendous.

If you think you have a roof moss problem, Roof Life of Oregon will provide a free roof inspection to ensure your roof stays in tip-top shape.

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